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DMAKE(p) Unsupported Free Software DMAKE(p)
NAME
dmake - maintain program groups, or interdependent files
SYNOPSIS
dmake [-ABceEhiknpqrsStTuVxX] [-v{dfimt}] [-P#] [-{f|C|K}
file] [macro[*][+][:]=value ...] [target ...]
DESCRIPTION
dmake executes commands found in an external file called a
makefile to update one or more target names. Each target
may depend on zero or more prerequisite targets. If any of
the target's prerequisites is newer than the target or if
the target itself does not exist, then dmake will attempt to
make the target.
If no -f command line option is present then dmake searches
for an existing makefile from the list of prerequisites
specified for the special target .MAKEFILES (see the STARTUP
section for more details). If "-" is the name of the file
specified to the -f flag then dmake uses standard input as
the source of the makefile text.
Any macro definitions (arguments with embedded "=" signs)
that appear on the command line are processed first and
supersede definitions for macros of the same name found
within the makefile. In general it is impossible for defin-
itions found inside the makefile to redefine a macro defined
on the command line, see the MACROS section for an excep-
tion.
If no target names are specified on the command line, then
dmake uses the first non-special target found in the
makefile as the default target. See the SPECIAL TARGETS
section for the list of special targets and their function.
dmake is a re-implementation of the UNIX Make utility with
significant enhancements. Makefiles written for most previ-
ous versions of Make will be handled correctly by dmake.
Known differences between dmake and other versions of make
are discussed in the COMPATIBILITY section found at the end
of this document.
OPTIONS
-A Enable AUGMAKE special inference rule transformations
(see the "PERCENT(%) RULES" section), these are set to
off by default.
-B Enable the use of spaces instead of <tabs> to begin
recipe lines. This flag equivalent to the .NOTABS spe-
cial macro and is further described below.
-c Use non-standard comment stripping. If you specify -c
then dmake will treat any # character as a start of
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comment character wherever it may appear unless it is
escaped by a \.
-C [+]file
This option writes to file a copy of standard output
and standard error from any child processes and from
the dmake process itself. If you specify a + prior to
the file name then the text is appended to the previous
contents of file. This option is active in the MSDOS
implementation only and is ignored by non-MSDOS ver-
sions of dmake.
-E Read the environment and define all strings of the form
'ENV-VAR=evalue' defined within as macros whose name is
ENV-VAR, and whose value is 'evalue'. The environment
is processed prior to processing the user specified
makefile thereby allowing definitions in the makefile
to override definitions in the environment.
-e Same as -E, except that the environment is processed
after the user specified makefile has been processed
(thus definitions in the environment override defini-
tions in the makefile). The -e and -E options are
mutually exclusive. If both are given the latter takes
effect.
-f file
Use file as the source for the makefile text. Only one
-f option is allowed.
-h Print the command summary for dmake.
-i Tells dmake to ignore errors, and continue making other
targets. This is equivalent to the .IGNORE attribute
or macro.
-K file
Turns on .KEEP_STATE state tracking and tells dmake to
use file as the state file.
-k Causes dmake to ignore errors caused by command execu-
tion and to make all targets not depending on targets
that could not be made. Ordinarily dmake stops after a
command returns a non-zero status, specifying -k causes
dmake to ignore the error and continue to make as much
as possible.
-n Causes dmake to print out what it would have executed,
but does not actually execute the commands. A special
check is made for the string "$(MAKE)" inside a recipe
line, if found, the line is expanded and invoked,
thereby enabling recursive makes to give a full
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description of all that they will do. The check for
"$(MAKE)" is disabled inside group recipes.
-p Print out a version of the digested makefile in human
readable form. (useful for debugging, but cannot be
re-read by dmake)
-P# On systems that support multi-processing cause dmake to
use # concurrent child processes to make targets. See
the "MULTI PROCESSING" section for more information.
-q Check and see if the target is up to date. Exits with
code 0 if up to date, 1 otherwise.
-r Tells dmake not to read the initial startup makefile,
see STARTUP section for more details.
-s Tells dmake to do all its work silently and not echo
the commands it is executing to stdout (also suppresses
warnings). This is equivalent to the .SILENT attri-
bute or macro.
-S Force sequential execution of recipes on architectures
which support concurrent makes. For backward compati-
bility with old makefiles that have nasty side-effect
prerequisite dependencies.
-t Causes dmake to touch the targets and bring them up to
date without executing any commands. Note that targets
will not be created if they do not already exist.
-T Tells dmake to not perform transitive closure on the
inference graph.
-u Force an unconditional update. (ie. do everything that
would be done if everything that a target depended on
was out of date)
-v[dfimt]
Verbose flag, when making targets print to stdout what
we are going to make and what we think its time stamp
is. The optional flags [dfimt] can be used to restrict
the information that is displayed. In the absence of
any optional flags all are assumed to be given (ie. -v
is equivalent to -vdfimt). The meanings of the
optional flags are:
d Notify of change directory operations only.
f Notify of file I/O operations only.
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i Notify of inference algorithm operation only.
m Notify of target update operations only.
t Keep any temporary files created; normally they
are automatically deleted.
-V Print the version of dmake, and values of builtin mac-
ros.
-x Upon processing the user makefile export all non-
internally defined macros to the user's environment.
This option together with the -e option allows SYSV
AUGMAKE recursive makes to function as expected.
-X Inhibit the execution of #! lines found at the begin-
ning of a makefile. The use of this flag prevents
non-termination of recursive make invocations.
INDEX
Here is a list of the sections that follow and a short
description of each. Perhaps you won't have to read the
whole man page to find what you need.
STARTUP Describes dmake initialization.
SYNTAX Describes the syntax of makefile expres-
sions.
ATTRIBUTES Describes the notion of attributes and
how they are used when making targets.
MACROS Defining and expanding macros.
RULES AND TARGETS How to define targets and their prere-
quisites.
RECIPES How to tell dmake how to make a target.
TEXT DIVERSIONS How to use text diversions in recipes and
macro expansions.
SPECIAL TARGETS Some targets are special.
SPECIAL MACROS Macros used by dmake to alter the pro-
cessing of the makefile, and those
defined by dmake for the user.
CONTROL MACROS Itemized list of special control macros.
RUN-TIME MACROS Discussion of special run-time macros
such as $@ and $<.
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FUNCTION MACROS GNU style function macros, only $(mktmp
...) for now.
DYNAMIC PREREQUISITES
Processing of prerequisites which contain
macro expansions in their name.
BINDING TARGETS The rules that dmake uses to bind a tar-
get to an existing file in the file sys-
tem.
PERCENT(%) RULES Specification of recipes to be used by
the inference algorithm.
MAKING INFERENCES The rules that dmake uses when inferring
how to make a target which has no expli-
cit recipe. This and the previous sec-
tion are really a single section in the
text.
MAKING TARGETS How dmake makes targets other than
libraries.
MAKING LIBRARIES How dmake makes libraries.
KEEP STATE A discussion of how .KEEP_STATE works.
MULTI PROCESSING Discussion of dmake's parallel make
facilities for architectures that support
them.
CONDITIONALS Conditional expressions which control the
processing of the makefile.
EXAMPLES Some hopefully useful examples.
COMPATIBILITY How dmake compares with previous versions
of make.
LIMITS Limitations of dmake.
PORTABILITY Comments on writing portable makefiles.
FILES Files used by dmake.
SEE ALSO Other related programs, and man pages.
AUTHOR The guy responsible for this thing.
BUGS Hope not.
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STARTUP
When dmake begins execution it first processes the command
line and then processes an initial startup-makefile. This
is followed by an attempt to locate and process a user sup-
plied makefile. The startup file defines the default values
of all required control macros and the set of default rules
for making targets and inferences. When searching for the
startup makefile, dmake searches the following locations, in
the order specified, until a startup file is located:
1. The location given as the value of the macro MAK-
ESTARTUP defined on the command line.
2. The location given as the value of the environment
variable MAKESTARTUP defined in the current
environment.
3. The location given as the value of the macro MAK-
ESTARTUP defined internally within dmake.
The above search is disabled by specifying the -r option on
the command line. An error is issued if a startup makefile
cannot be found and the -r option was not specified. A user
may substitute a custom startup file by defining the MAKES-
TARTUP environment variable or by redefining the MAKESTARTUP
macro on the command line. To determine where dmake looks
for the default startup file, check your environment or
issue the command "dmake -V".
A similar search is performed to locate a default user
makefile when no -f command line option is specified. By
default, the prerequisite list of the special target
.MAKEFILES specifies the names of possible makefiles and the
search order that dmake should use to determine if one
exists. A typical definition for this target is:
.MAKEFILES : makefile.mk Makefile makefile
dmake will first look for makefile.mk and then the others.
If a prerequisite cannot be found dmake will try to make it
before going on to the next prerequisite. For example,
makefile.mk can be checked out of an RCS file if the proper
rules for doing so are defined in the startup file.
If the first line of the user makefile is of the form:
#! command command_args
then dmake will expand and run the command prior to reading
any addtional input. If the return code of the command is
zero then dmake will continue on to process the remainder of
the user makefile, if the return code is non-zero then dmake
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will exit.
SYNTAX
This section is a summary of the syntax of makefile state-
ments. The description is given in a style similar to BNF,
where { } enclose items that may appear zero or more times,
and [ ] enclose items that are optional. Alternative pro-
ductions for a left hand side are indicated by '->', and
newlines are significant. All symbols in bold type are text
or names representing text supplied by the user.
Makefile -> { Statement }
Statement -> Macro-Definition
-> Conditional
-> Rule-Definition
-> Attribute-Definition
Macro-Definition -> MACRO = LINE
-> MACRO *= LINE
-> MACRO := LINE
-> MACRO *:= LINE
-> MACRO += LINE
-> MACRO +:= LINE
Conditional -> .IF expression
Makefile
[ .ELIF expression
Makefile ]
[ .ELSE
Makefile ]
.END
expression -> LINE
-> STRING == LINE
-> STRING != LINE
Rule-Definition -> target-definition
[ recipe ]
target-definition -> targets [attrs] op { PREREQUISITE } [; rcp-line]
targets -> target { targets }
-> "target" { targets }
target -> special-target
-> TARGET
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attrs -> attribute { attrs }
-> "attribute" { attrs }
op -> : { modifier }
modifier -> :
-> ^
-> !
-> -
recipe -> { TAB rcp-line }
-> [@][%][-] [
{ LINE }
]
rcp-line -> [@][%][-][+] LINE
Attribute-Definition -> attrs : targets
attribute -> .EPILOG
-> .IGNORE
-> .LIBRARY
-> .MKSARGS
-> .NOINFER
-> .NOSTATE
-> .PHONY
-> .PRECIOUS
-> .PROLOG
-> .SETDIR=path
-> .SILENT
-> .SEQUENTIAL
-> .SWAP
-> .USESHELL
-> .SYMBOL
-> .UPDATEALL
special-target -> .ERROR
-> .EXPORT
-> .GROUPEPILOG
-> .GROUPPROLOG
-> .IMPORT
-> .INCLUDE
-> .INCLUDEDIRS
-> .MAKEFILES
-> .REMOVE
-> .SOURCE
-> .SOURCE.suffix
-> .suffix1.suffix2
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Where, TAB represents a <tab> character, STRING represents
an arbitrary sequence of characters, and LINE represents a
possibly empty sequence of characters terminated by a non-
escaped (not immediately preceded by a backslash '\') new-
line character. MACRO, PREREQUISITE, and TARGET each
represent a string of characters not including space or tab
which respectively form the name of a macro, prerequisite or
target. The name may itself be a macro expansion expres-
sion. A LINE can be continued over several physical lines
by terminating it with a single backslash character. Com-
ments are initiated by the pound # character and extend to
the end of line. All comment text is discarded, a '#' may
be placed into the makefile text by escaping it with '\'
(ie. \# translates to # when it is parsed). An exception to
this occurs when a # is seen inside a recipe line that
begins with a <tab> or is inside a group recipe. If you
specify the -c command line switch then this behavior is
disabled and dmake will treat all # characters as start of
comment indicators unless they are escaped by \. A set of
continued lines may be commented out by placing a single #
at the start of the first line. A continued line cannot
span more than one makefile.
white space is defined to be any combination of <space>,
<tab>, and the sequence \<nl> when \<nl> is used to ter-
minate a LINE. When processing macro definition lines, any
amount of white space is allowed on either side of the macro
operator (=, *=, :=, *:=, += or +:=), and white space is
stripped from both before and after the macro value string.
The sequence \<nl> is treated as white space during recipe
expansion and is deleted from the final recipe string. You
must escape the \<nl> with another \ in order to get a \ at
the end of a recipe line. The \<nl> sequence is deleted
from macro values when they are expanded.
When processing target definition lines, the recipe for a
target must, in general, follow the first definition of the
target (See the RULES AND TARGETS section for an exception),
and the recipe may not span across multiple makefiles. Any
targets and prerequisites found on a target definition line
are taken to be white space separated tokens. The rule
operator (op in SYNTAX section) is also considered to be a
token but does not require white space to precede or follow
it. Since the rule operator begins with a `:', traditional
versions of make do not allow the `:' character to form a
valid target name. dmake allows `:' to be present in
target/prerequisite names as long as the entire
target/prerequisite name is quoted. For example:
a:fred : test
would be parsed as TARGET = a, PREREQUISITES={fred, :,
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test}, which is not what was intended. To fix this you must
write:
"a:fred" : test
Which will be parsed as expected. Quoted target and prere-
quisite specifications may also contain white space thereby
allowing the use of complex function macro expressions..
See the EXAMPLES section for how to apply " quoting to a
list of targets.
ATTRIBUTES
dmake defines several target attributes. Attributes may be
assigned to a single target, a group of targets, or to all
targets in the makefile. Attributes are used to modify
dmake actions during target update. The recognized attri-
butes are:
.EPILOG Insert shell epilog code when executing a group
recipe associated with any target having this
attribute set.
.IGNORE Ignore an error when trying to make any target
with this attribute set.
.LIBRARY Target is a library.
.MKSARGS If running in an MSDOS environment then use MKS
extended argument passing conventions to pass
arguments to commands. Non-MSDOS environments
ignore this attribute.
.NOINFER Any target with this attribute set will not be
subjected to transitive closure if it is
inferred as a prerequisite of a target whose
recipe and prerequisites are being inferred.
(i.e. the inference algorithm will not use any
prerequisite with this attribute set, as a tar-
get) If specified as '.NOINFER:' (ie. with no
prerequisites or targets) then the effect is
equivalent to specifying -T on the command line.
.NOSTATE Any target with this attribute set will not have
command line flag information stored in the
state file if .KEEP_STATE has been enabled.
.PHONY Any target with this attribute set will have its
recipe executed each time the target is made
even if a file matching the target name can be
located. Any targets that have a .PHONY attri-
buted target as a prerequisite will be made each
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time the .PHONY attributed prerequisite is made.
.PRECIOUS Do not remove associated target under any cir-
cumstances. Set by default for any targets
whose corresponding files exist in the file sys-
tem prior to the execution of dmake.
.PROLOG Insert shell prolog code when executing a group
recipe associated with any target having this
attribute set.
.SEQUENTIAL Force a sequential make of the associated
target's prerequisites.
.SETDIR Change current working directory to specified
directory when making the associated target.
You must specify the directory at the time the
attribute is specified. To do this simply give
.SETDIR=path as the attribute. path is expanded
and the result is used as the value of the
directory to change to. If path is surrounded
by single quotes then path is not expanded, and
is used literally as the directory name. If the
path contains any `:' characters then the entire
attribute string must be quoted using ". If a
target having this attribute set also has the
.IGNORE attribute set then if the change to the
specified directory fails it will be ignored,
and no error message will be issued.
.SILENT Do not echo the recipe lines when making any
target with this attribute set, and do not issue
any warnings.
.SWAP Under MSDOS when making a target with this
attribute set swap the dmake executable to disk
prior to executing the recipe line. Also see
the '%' recipe line flag defined in the RECIPES
section.
.SYMBOL Target is a library member and is an entry point
into a module in the library. This attribute is
used only when searching a library for a target.
Targets of the form lib((entry)) have this
attribute set automatically.
.USESHELL Force each recipe line of a target to be exe-
cuted using a shell. Specifying this attribute
is equivalent to specifying the '+' character at
the start of each line of a non-group recipe.
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.UPDATEALL Indicates that all the targets listed in this
rule are updated by the execution of the accom-
panying recipe. A common example is the produc-
tion of the y.tab.c and y.tab.h files by yacc
when it is run on a grammar. Specifying
.UPDATEALL in such a rule prevents the running
of yacc twice, once for the y.tab.c file and
once for the y.tab.h file.
All attributes are user setable and except for .UPDATEALL,
.SETDIR and .MKSARGS may be used in one of two forms. The
.MKSARGS attribute is restricted to use as a global attri-
bute, and the use of the .UPDATEALL and .SETDIR attributes
is restricted to rules of the second form only.
ATTRIBUTE_LIST : targets
assigns the attributes specified by ATTRIBUTE_LIST to each
target in targets or
targets ATTRIBUTE_LIST : ...
assigns the attributes specified by ATTRIBUTE_LIST to each
target in targets. In the first form if targets is empty
(ie. a NULL list), then the list of attributes will apply to
all targets in the makefile (this is equivalent to the com-
mon Make construct of ".IGNORE :" but has been modified to
the notion of an attribute instead of a special target).
Not all of the attributes have global meaning. In particu-
lar, .LIBRARY, .NOSTATE, .PHONY, .SETDIR, .SYMBOL and
.UPDATEALL have no assigned global meaning.
Any attribute may be used with any target, even with the
special targets. Some combinations are useless (e.g.
.INCLUDE .PRECIOUS: ... ), while others are useful (e.g.
.INCLUDE .IGNORE : "file.mk" will not complain if file.mk
cannot be found using the include file search rules, see the
section on SPECIAL TARGETS for a description of .INCLUDE).
If a specified attribute will not be used with the special
target a warning is issued and the attribute is ignored.
MACROS
dmake supports six types of macro assignment.
MACRO = LINE This is the most common and familiar form of
macro assignment. It assigns LINE literally
as the value of MACRO. Future expansions of
MACRO recursively expand its value.
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MACRO *= LINE This form behaves exactly as the simple '='
form with the exception that if MACRO
already has a value then the assignment is
not performed.
MACRO := LINE This form differs from the simple '=' form
in that it expands LINE prior to assigning
it as the value of MACRO. Future expansions
of MACRO do not recursively expand its
value.
MACRO *:= LINE This form behaves exactly as the ':=' form
with the exception that if MACRO already has
a value then the assignment and expansion
are not performed.
MACRO += LINE This form of macro assignment allows macro
values to grow. It takes the literal value
of LINE and appends it to the previous value
of MACRO separating the two by a single
space. Future expansions of MACRO recur-
sively expand its value.
MACRO +:= LINE This form is similar to the '+=' form except
that the value of LINE is expanded prior to
being added to the value of MACRO.
Macro expressions specified on the command line allow the
macro value to be redefined within the makefile only if the
macro is defined using the '+=' and '+:=' operators. Other
operators will define a macro that cannot be further modi-
fied.
When dmake defines a non-environment macro it strips leading
and trailing white space from the macro value. Macros
imported from the environment via either the .IMPORT special
target (see the SPECIAL TARGETS section), or the -e, or -E
flags are an exception to this rule. Their values are
always taken literally and white space is never stripped.
In addition, named macros defined using the .IMPORT special
target do not have their values expanded when they are used
within a makefile. In contrast, environment macros that are
imported due to the specification of the -e or -E flags are
subject to expansion when used.
To specify a macro expansion enclose the name in () or {}
and precede it with a dollar sign $. Thus $(TEST)
represents an expansion of the macro variable named TEST.
If TEST is defined then $(TEST) is replaced by its expanded
value. If TEST is not defined then $(TEST) expands to the
NULL string (this is equivalent to defining a macro as
'TEST=' ). A short form may be used for single character
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named macros. In this case the parentheses are optional,
and $(I) is equivalent to $I. Macro expansion is recursive,
hence, if the value string contains an expression represent-
ing a macro expansion, the expansion is performed. Circular
macro expansions are detected and cause an error to be
issued.
When defining a macro the given macro name is first expanded
before being used to define the macro. Thus it is possible
to define macros whose names depend on values of other mac-
ros. For example, suppose CWD is defined as
CWD = $(PWD:b)
then the value of $(CWD) is the name of the current direc-
tory. This can be used to define macros specific to this
directory, for example:
_$(CWD).prt = list of files to print...
The actual name of the defined macro is a function of the
current directory. A construct such as this is useful when
processing a hierarchy of directories using .SETDIR attri-
buted targets and a collection of small distributed makefile
stubs.
Macro variables may be defined within the makefile, on the
command line, or imported from the environment.
dmake supports several non-standard macro expansions: The
first is of the form:
$(macro_name:modifier_list:modifier_list:...)
where modifier_list is chosen from the set { D or d, F or f,
B or b, S or s, T or t } and
d - directory portion of all path names
f - file (including suffix) portion of path names
b - file (not including suffix) portion of path names
s - simple pattern substitution
t - tokenization.
Thus if we have the example:
test = d1/d2/d3/a.out f.out d1/k.out
The following macro expansions produce the values on the
right of '->' after expansion.
$(test:d) -> d1/d2/d3/ d1/
$(test:b) -> a f k
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$(test:f) -> a.out f.out k.out
${test:db} -> d1/d2/d3/a f d1/k
${test:s/out/in/:f} -> a.in f.in k.in
$(test:f:t"+") -> a.out+f.out+k.out
If a token ends in a string composed from the value of the
macro DIRBRKSTR (ie. ends in a directory separator string,
e.g. '/' in UNIX) and you use the :d modifier then the
expansion returns the directory name less the final direc-
tory separator string. Thus successive pairs of :d modif-
iers each remove a level of directory in the token string.
The tokenization modifier takes all white space separated
tokens from the macro value and separates them by the quoted
separator string. The separator string may contain the fol-
lowing escape codes \a => <bel>, \b => <backspace>, \f =>
<formfeed>, \n => <nl>, \r => <cr>, \t => <tab>, \v =>
<vertical tab>, \" => ", and \xxx => <xxx> where xxx is the
octal representation of a character. Thus the expansion:
$(test:f:t"+\n")
produces:
a.out+
f.out+
k.out
The second non-standard form of macro expansion allows for
recursive macros. It is possible to specify a $(macro_name)
or ${macro_name} expansion where macro_name contains more $(
... ) or ${ ... } macro expansions itself.
For example $(CC$(_HOST)$(_COMPILER)) will first expand
CC$(_HOST)$(_COMPILER) to get a result and use that result
as the name of the macro to expand. This is useful for
writing a makefile for more than one target environment. As
an example consider the following hypothetical case. Suppose
that _HOST and _COMPILER are imported from the environment
and are set to represent the host machine type and the host
compiler respectively.
CFLAGS_VAX_CC = -c -O # _HOST == "_VAX", _COMPILER == "_CC"
CFLAGS_PC_MSC = -c -ML # _HOST == "_PC", _COMPILER == "_MSC"
# redefine CFLAGS macro as:
CFLAGS := $(CFLAGS$(_HOST)$(_COMPILER))
This causes CFLAGS to take on a value that corresponds to
the environment in which the make is being invoked.
The final non-standard macro expansion is of the form:
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string1{token_list}string2
where string1, string2 and token_list are expanded. After
expansion, string1 is prepended to each token found in
token_list and string2 is appended to each resulting token
from the previous prepend. string1 and string2 are not del-
imited by white space whereas the tokens in token_list are.
A null token in the token list is specified using "". Thus
using another example we have:
test/{f1 f2}.o --> test/f1.o test/f2.o
test/ {f1 f2}.o --> test/ f1.o f2.o
test/{f1 f2} .o --> test/f1 test/f2 .o
test/{"f1" ""}.o --> test/f1.o test/.o
and
test/{d1 d2}/{f1 f2}.o --> test/d1/f1.o test/d1/f2.o
test/d2/f1.o test/d2/f2.o
This last expansion is activated only when the first charac-
ters of token_list appear immediately after the opening '{'
with no intervening white space. The reason for this res-
triction is the following incompatibility with Bourne Shell
recipes. The line
{ echo hello;}
is valid /bin/sh syntax; while
{echo hello;}
is not. Hence the latter triggers the enhanced macro expan-
sion while the former causes it to be suppressed. See the
SPECIAL MACROS section for a description of the special mac-
ros that dmake defines and understands.
RULES AND TARGETS
A makefile contains a series of entries that specify depen-
dencies. Such entries are called target/prerequisite or
rule definitions. Each rule definition is optionally fol-
lowed by a set of lines that provide a recipe for updating
any targets defined by the rule. Whenever dmake attempts to
bring a target up to date and an explicit recipe is provided
with a rule defining the target, that recipe is used to
update the target. A rule definition begins with a line
having the following syntax:
<targets> [<attributes>] <ruleop> [<prerequisites>] [;<recipe>]
targets is a non-empty list of targets. If the target is a
special target (see SPECIAL TARGETS section below) then it
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DMAKE(p) Unsupported Free Software DMAKE(p)
must appear alone on the rule line. For example:
.IMPORT .ERROR : ...
is not allowed since both .IMPORT and .ERROR are special
targets. Special targets are not used in the construction
of the dependency graph and will not be made.
attributes is a possibly empty list of attributes. Any
attribute defined in the ATTRIBUTES section above may be
specified. All attributes will be applied to the list of
named targets in the rule definition. No other targets will
be affected.
NOTE: As stated earlier, if both the target list and
prerequisite list are empty but the attributes list
is not, then the specified attributes affect all
targets in the makefile.
ruleop is a separator which is used to identify the targets
from the prerequisites. Optionally it also provides a
facility for modifying the way in which dmake handles the
making of the associated targets. In its simplest form the
operator is a single ':', and need not be separated by white
space from its neighboring tokens. It may additionally be
followed by any of the modifiers { !, ^, -, : }, where:
! says execute the recipe for the associated targets once
for each out of date prerequisite. Ordinarily the
recipe is executed once for all out of date prere-
quisites at the same time.
^ says to insert the specified prerequisites, if any,
before any other prerequisites already associated with
the specified targets. In general, it is not useful to
specify ^ with an empty list of prerequisites.
- says to clear the previous list of prerequisites before
adding the new prerequisites. Thus,
.SUFFIXES :
.SUFFIXES : .a .b
can be replaced by
.SUFFIXES :- .a .b
however the old form still works as expected. NOTE:
.SUFFIXES is ignored by dmake it is used here simply as
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DMAKE(p) Unsupported Free Software DMAKE(p)
an example.
: When the rule operator is not modified by a second ':'
only one set of rules may be specified for making a
target. Multiple definitions may be used to add to the
list of prerequisites that a target depends on. How-
ever, if a target is multiply defined only one defini-
tion may specify a recipe for making the target.
When a target's rule operator is modified by a second
':' (:: for example) then this definition may not be
the only definition with a recipe for the target.
There may be other :: target definition lines that
specify a different set of prerequisites with a dif-
ferent recipe for updating the target. Any such target
is made if any of the definitions find it to be out of
date with respect to the related prerequisites and the
corresponding recipe is used to update the target.
In the following simple example, each rule has a `::'
ruleop. In such an operator we call the first `:' the
operator, and the second `:' the modifier.
a.o :: a.c b.h
first recipe for making a.o
a.o :: a.y b.h
second recipe for making a.o
If a.o is found to be out of date with respect to a.c
then the first recipe is used to make a.o. If it is
found out of date with respect to a.y then the second
recipe is used. If a.o is out of date with respect to
b.h then both recipes are invoked to make a.o. In the
last case the order of invocation corresponds to the
order in which the rule definitions appear in the
makefile.
Targets defined using a single `:' operator with a recipe
may be redefined again with a new recipe by using a `:'
operator with a `:' modifier. This is equivalent to a tar-
get having been initially defined with a rule using a `:'
modifier. Once a target is defined using a `:' modifier it
may not be defined again with a recipe using only the `:'
operator with no `:' modifier. In both cases the use of a
`:' modifier creates a new list of prerequisites and makes
it the current prerequisite list for the target. The `:'
operator with no recipe always modifies the current list of
prerequisites. Thus assuming each of the following defini-
tions has a recipe attached, then:
joe : fred ... (1)
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DMAKE(p) Unsupported Free Software DMAKE(p)
joe :: more ... (2)
and
joe :: fred ... (3)
joe :: more ... (4)
are legal and mean: add the recipe associated with (2), or
(4) to the set of recipes for joe, placing them after exist-
ing recipes for making joe. The constructs:
joe :: fred ... (5)
joe : more ... (6)
and
joe : fred ... (7)
joe : more ... (8)
are errors since we have two sets of perfectly good recipes
for making the target.
prerequisites is a possibly empty list of targets that must
be brought up to date before making the current target.
recipe is a short form and allows the user to specify short
rule definitions on a single line. It is taken to be the
first recipe line in a larger recipe if additional lines
follow the rule definition. If the semi-colon is present
but the recipe line is empty (ie. null string) then it is
taken to be an empty rule. Any target so defined causes the
Don't know how to make ... error message to be suppressed
when dmake tries to make the target and fails. This silence
is maintained for rules that are terminated by a semicolon
and have no following recipe lines, for targets listed on
the command line, for the first target found in the
makefile, and for any target having no recipe but containing
a list of prerequisites (see the COMPATIBILITY section for
an exception to this rule if the AUGMAKE (-A) flag was
specified.
RECIPES
The traditional format used by most versions of Make defines
the recipe lines as arbitrary strings that may contain macro
expansions. They follow a rule definition line and may be
spaced apart by comment or blank lines. The list of recipe
lines defining the recipe is terminated by a new target
definition, a macro definition, or end-of-file. Each recipe
line MUST begin with a <TAB> character which may optionally
be followed with one or all of the characters '@%+-'. The
'-' indicates that non-zero exit values (ie. errors) are to
be ignored when this recipe line is executed, the '+'
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DMAKE(p) Unsupported Free Software DMAKE(p)
indicates that the current recipe line is to be executed
using the shell, the '%' indicates that dmake should swap
itself out to secondary storage (MSDOS only) before running
the recipe and the '@' indicates that the recipe line should
NOT be echoed to the terminal prior to being executed. Each
switch is off by default (ie. by default, errors are signi-
ficant, commands are echoed, no swapping is done and a shell
is used only if the recipe line contains a character found
in the value of the SHELLMETAS macro). Global settings
activated via command line options or special attribute or
target names may also affect these settings. An example
recipe:
target :
first recipe line
second recipe line, executed independently of the first.
@a recipe line that is not echoed
-and one that has errors ignored
%and one that causes dmake to swap out
+and one that is executed using a shell.
The second and new format of the recipe block begins the
block with the character '[' (the open group character) in
the last non-white space position of a line, and terminates
the block with the character ']' (the close group character)
in the first non-white space position of a line. In this
form each recipe line need not have a leading TAB. This is
called a recipe group. Groups so defined are fed intact as
a single unit to a shell for execution whenever the
corresponding target needs to be updated. If the open group
character '[' is preceded by one or all of -, @ or % then
they apply to the entire group in the same way that they
apply to single recipe lines. You may also specify '+' but
it is redundant as a shell is already being used to run the
recipe. See the MAKING TARGETS section for a description of
how dmake invokes recipes. Here is an example of a group
recipe:
target :
[
first recipe line
second recipe line
all of these recipe lines are fed to a
single copy of a shell for execution.
]
TEXT DIVERSIONS
dmake supports the notion of text diversions. If a recipe
line contains the macro expression
$(mktmp[,[file][,text]] data)
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DMAKE(p) Unsupported Free Software DMAKE(p)
then all text contained in the data expression is expanded
and is written to a temporary file. The return value of the
macro is the name of the temporary file.
data can be any text and must be separated from the 'mktmp'
portion of the macro name by white-space. The only restric-
tion on the data text is that it must contain a balanced
number of parentheses of the same kind as are used to ini-
tiate the $(mktmp ...) expression. For example:
$(mktmp $(XXX))
is legal and works as expected, but:
$(mktmp text (to dump to file)
is not legal. You can achieve what you wish by either
defining a macro that expands to '(' or by using {} in the
macro expression; like this:
${mktmp text (to dump to file}
Since the temporary file is opened when the macro containing
the text diversion expression is expanded, diversions may
now be nested and any diversions that are created as part of
':=' macro expansions persist for the duration of the dmake
run. The diversion text may contain the same escape codes
as those described in the MACROS section. Thus if the data
text is to contain new lines they must be inserted using the
\n escape sequence. For example the expression:
all:
cat $(mktmp this is a\n\
test of the text diversion\n)
is replaced by:
cat /tmp/mk12294AA
where the temporary file contains two lines both of which
are terminated by a new-line. If the data text spans multi-
ple lines in the makefile then each line must be continued
via the use of a \. A second more illustrative example gen-
erates a response file to an MSDOS link command:
OBJ = fred.obj mary.obj joe.obj
all : $(OBJ)
link @$(mktmp $(^:t"+\n")\n)
The result of making `all' in the second example is the com-
mand:
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DMAKE(p) Unsupported Free Software DMAKE(p)
link @/tmp/mk02394AA
where the temporary file contains:
fred.obj+
mary.obj+
joe.obj
The last line of the file is terminated by a new-line which
is inserted due to the \n found at the end of the data
string.
If the optional file specifier is present then its expanded
value is the name of the temporary file to create. Whenever
a $(mktmp ...) macro is expanded the macro $(TMPFILE) is set
to a new temporary file name. Thus the construct:
$(mktmp,$(TMPFILE) data)
is completely equivalent to not specifying the $(TMPFILE)
optional argument. Another example that would be useful for
MSDOS users with a Turbo-C compiler
$(mktmp,turboc.cfg $(CFLAGS))
will place the contents of CFLAGS into a local turboc.cfg
file. The second optional argument, text, if present alters
the name of the value returned by the $(mktmp ...) macro.
Under MS-DOS text diversions may be a problem. Many DOS
tools require that path names which contain directories use
the \ character to delimit the directories. Some users how-
ever wish to use the '/' to delimit pathnames and use
environments that allow them to do so. The macro USESHELL
is set to "yes" if the current recipe is forced to use a
shell via the .USESHELL or '+' directives, otherwise its
value is "no". The dmake startup files define the macro
DIVFILE whose value is either the value of TMPFILE or the
value of TMPFILE edited to replace any '/' characters to the
appropriate value based on the current shell and whether it
will be used to execute the recipe.
Previous versions of dmake defined text diversions using <+,
+> strings, where <+ started a text diversion and +> ter-
minated one. dmake is backward compatible with this con-
struct if the <+ and +> appear literally on the same recipe
line or in the same macro value string. In such instances
the expression:
<+data+>
is mapped to:
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DMAKE(p) Unsupported Free Software DMAKE(p)
$(mktmp data)
which is fully output compatible with the earlier construct.
<+, +> constructs whose text spans multiple lines must be
converted by hand to use $(mktmp ...).
If the environment variable TMPDIR is defined then the tem-
porary file is placed into the directory specified by that
variable. A makefile can modify the location of temporary
files by defining a macro named TMPDIR and exporting it
using the .EXPORT special target.
SPECIAL TARGETS
This section describes the special targets that are recog-
nized by dmake. Some are affected by attributes and others
are not.
.ERROR If defined then the recipe associated with
this target is executed whenever an error con-
dition is detected by dmake. All attributes
that can be used with any other target may be
used with this target. Any prerequisites of
this target will be brought up to date during
its processing. NOTE: errors will be ignored
while making this target, in extreme cases
this may cause some problems.
.EXPORT All prerequisites associated with this target
are assumed to correspond to macro names and
they and their values are exported to the
environment as environment strings at the
point in the makefile at which this target
appears. Any attributes specified with this
target are ignored. Only macros which have
been assigned a value in the makefile prior to
the export directive are exported, macros as
yet undefined or macros whose value contains
any of the characters "+=:*" are not exported.
is suppre
.IMPORT Prerequisite names specified for this target
are searched for in the environment and
defined as macros with their value taken from
the environment. If the special name .EVERY-
THING is used as a prerequisite name then all
environment variables defined in the environ-
ment are imported. The functionality of the
-E flag can be forced by placing the construct
.IMPORT : .EVERYTHING at the start of a
makefile. Similarly, by placing the construct
at the end, one can emulate the effect of the
-e command line flag. If a prerequisite name
Version 3.8 PL1 UW 23
DMAKE(p) Unsupported Free Software DMAKE(p)
cannot be found in the environment an error
message is issued. .IMPORT accepts the
.IGNORE attribute. When given, it causes
dmake to ignore the above error. See the MAC-
ROS section for a description of the process-
ing of imported macro values.
.INCLUDE Parse another makefile just as if it had been
located at the point of the .INCLUDE in the
current makefile. The list of prerequisites
gives the list of makefiles to try to read.
If the list contains multiple makefiles then
they are read in order from left to right.
The following search rules are used when try-
ing to locate the file. If the filename is
surrounded by " or just by itself then it is
searched for in the current directory. If it
is not found it is then searched for in each
of the directories specified for the .INCLU-
DEDIRS special target. If the file name is
surrounded by < and >, (ie.
<my_spiffy_new_makefile>) then it is searched
for only in the directories given by the
.INCLUDEDIRS special target. In both cases if
the file name is a fully qualified name start-
ing at the root of the file system then it is
only searched for once, and the .INCLUDEDIRS
list is ignored. .INCLUDE accepts the .IGNORE
and .SETDIR attributes. If .IGNORE attribute
is given and the file cannot be found then
dmake continues processing, otherwise an error
message is generated. The .SETDIR attribute
causes dmake to change directories to the
specified directory prior to attempting the
include operation.
.INCLUDEDIRS The list of prerequisites specified for this
target defines the set of directories to
search when trying to include a makefile.
.KEEP_STATE This special target is a synonym for the macro
definition
.KEEP_STATE := _state.mk
It's effect is to turn on STATE keeping and to
define _state.mk as the state file.
.MAKEFILES The list of prerequisites is the set of files
to try to read as the default makefile. By
default this target is defined as:
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DMAKE(p) Unsupported Free Software DMAKE(p)
.MAKEFILES : makefile.mk Makefile
makefile
.SOURCE The prerequisite list of this target defines a
set of directories to check when trying to
locate a target file name. See the section on
BINDING of targets for more information.
.SOURCE.suff The same as .SOURCE, except that the
.SOURCE.suff list is searched first when try-
ing to locate a file matching the a target
whose name ends in the suffix .suff.
.REMOVE The recipe of this target is used whenever
dmake needs to remove intermediate targets
that were made but do not need to be kept
around. Such targets result from the applica-
tion of transitive closure on the dependency
graph.
In addition to the special targets above, several other
forms of targets are recognized and are considered special,
their exact form and use is defined in the sections that
follow.
SPECIAL MACROS
dmake defines a number of special macros. They are divided
into three classes: control macros, run-time macros, and
function macros. The control macros are used by dmake to
configure its actions, and are the preferred method of doing
so. In the case when a control macro has the same function
as a special target or attribute they share the same name as
the special target or attribute. The run-time macros are
defined when dmake makes targets and may be used by the user
inside recipes. The function macros provide higher level
functions dealing with macro expansion and diversion file
processing.
CONTROL MACROS
To use the control macros simply assign them a value just
like any other macro. The control macros are divided into
three groups: string valued macros, character valued macros,
and boolean valued macros.
The following are all of the string valued macros. This
list is divided into two groups. The first group gives the
string valued macros that are defined internally and cannot
be directly set by the user.
DIRBRKSTR Contains the string of chars used to terminate
the name of a directory in a pathname. Under
Version 3.8 PL1 UW 25
DMAKE(p) Unsupported Free Software DMAKE(p)
UNIX its value is "/", under MSDOS its value
is "/\:".
INCDEPTH This macro's value is a string of digits
representing the current depth of makefile
inclusion. In the first makefile level this
value is zero.
MFLAGS Is the list of flags that were given on the
command line including a leading switch char-
acter. The -f flag is not included in this
list.
MAKECMD Is the name with which dmake was invoked.
MAKEDIR Is the full path to the initial directory in
which dmake was invoked.
MAKEFILE Contains the string "-f makefile" where,
makefile is the name of initial user makefile
that was first read.
MAKEFLAGS Is the same as $(MFLAGS) but has no leading
switch character. (ie. MFLAGS = -$(MAKEFLAGS))
MAKEMACROS Contains the complete list of macro expres-
sions that were specified on the command line.
MAKETARGETS Contains the name(s) of the target(s), if any,
that were specified on the command line.
MAXPROCESSLIMIT
Is a numeric string representing the maximum
number of processes that dmake can use when
making targets using parallel mode.
NULL Is permanently defined to be the NULL string.
This is useful when comparing a conditional
expression to an NULL value.
PWD Is the full path to the current directory in
which make is executing.
TMPFILE Is set to the name of the most recent tem-
porary file opened by dmake. Temporary files
are used for text diversions and for group
recipe processing.
TMD Stands for "To Make Dir", and is the path from
the present directory (value of $(PWD)) to the
directory that dmake was started up in (value
of $(MAKEDIR)). This macro is modified when
Version 3.8 PL1 UW 26
DMAKE(p) Unsupported Free Software DMAKE(p)
.SETDIR attributes are processed.
USESHELL The value of this macro is set to "yes" if the
current recipe is forced to use a shell for
its execution via the .USESHELL or '+' direc-
tives, its value is "no" otherwise.
The second group of string valued macros control dmake
behavior and may be set by the user.
.NOTABS When set to non-NULL enables the use of
spaces as well as <tabs> to begin recipe
lines. By default a non-group recipe is
terminated by a line without any leading
white-space or by a line not beggining with
a <tab> character. Enabling this mode modi-
fies the first condition of the above termi-
nation rule to terminate a non-group recipe
with a line that contains only white-space.
This mode does not effect the parsing of
group recipes bracketed by [].
.SETDIR If this macro is assigned a value then dmake
will change to the directory given by that
value before making any targets.
AUGMAKE If set to a non NULL value will enable the
transformation of special meta targets to
support special AUGMAKE inferences (See the
COMPATIBILITY section).
DIRSEPSTR Contains the string that is used to separate
directory components when path names are
constructed. It is defined with a default
value at startup.
DIVFILE Is defined in the startup file and gives the
name that should be returned for the diver-
sion file name when used in $(mktmp ...)
expansions, see the TEXT DIVERSION section
for details.
.KEEP_STATE Assigning this macro a value tells dmake the
name of the state file to use and turns on
the keeping of state information for any
targets that are brought up to date by the
make.
GROUPFLAGS This macro gives the set of flags to pass to
the shell when invoking it to execute a
group recipe. The value of the macro is the
Version 3.8 PL1 UW 27
DMAKE(p) Unsupported Free Software DMAKE(p)
list of flags with a leading switch indica-
tor. (ie. `-' under UNIX)
GROUPSHELL This macro defines the full path to the exe-
cutable image to be used as the shell when
processing group recipes. This macro must
be defined if group recipes are used. It is
assigned a default value in the startup
makefile. Under UNIX this value is /bin/sh.
GROUPSUFFIX If defined, this macro gives the string to
use as a suffix when creating group recipe
files to be handed to the command inter-
preter. For example, if it is defined as
.sh, then all temporary files created by
dmake will end in the suffix .sh. Under
MSDOS if you are using command.com as your
GROUPSHELL, then this suffix must be set to
.bat in order for group recipes to function
correctly. The setting of GROUPSUFFIX and
GROUPSHELL is done automatically for
command.com in the startup.mk files.
MAKE Is defined in the startup file by default.
The string $(MAKE) is recognized when using
the -n option for single line recipes. Ini-
tially this macro is defined to have the
value "$(MAKECMD) $(MFLAGS)".
MAKESTARTUP This macro defines the full path to the ini-
tial startup makefile. Use the -V command
line option to discover its initial value.
MAXLINELENGTH This macro defines the maximum size of a
single line of makefile input text. The
size is specified as a number, the default
value is defined internally and is shown via
the -V option. A buffer of this size plus 2
is allocated for reading makefile text. The
buffer is freed before any targets are made,
thereby allowing files containing long input
lines to be processed without consuming
memory during the actual make. This macro
can only be used to extend the line length
beyond it's default minimum value.
MAXPROCESS Specify the maximum number of child
processes to use when making targets. The
default value of this macro is "1" and its
value cannot exceed the value of the macro
MAXPROCESSLIMIT. Setting the value of MAX-
PROCESS on the command line or in the
Version 3.8 PL1 UW 28
DMAKE(p) Unsupported Free Software DMAKE(p)
makefile is equivalent to supplying a
corresponding value to the -P flag on the
command line.
PREP This macro defines the number of iterations
to be expanded automatically when processing
% rule definitions of the form:
% : %.suff
See the sections on PERCENT(%) RULES for
details on how PREP is used.
SHELL This macro defines the full path to the exe-
cutable image to be used as the shell when
processing single line recipes. This macro
must be defined if recipes requiring the
shell for execution are to be used. It is
assigned a default value in the startup
makefile. Under UNIX this value is /bin/sh.
SHELLFLAGS This macro gives the set of flags to pass to
the shell when invoking it to execute a sin-
gle line recipe. The value of the macro is
the list of flags with a leading switch
indicator. (ie. `-' under UNIX)
SHELLMETAS Each time dmake executes a single recipe
line (not a group recipe) the line is
searched for any occurrence of a character
defined in the value of SHELLMETAS. If such
a character is found the recipe line is
defined to require a shell to ensure its
correct execution. In such instances a
shell is used to invoke the recipe line. If
no match is found the recipe line is exe-
cuted without the use of a shell.
There is only one character valued macro defined by dmake:
SWITCHAR contains the switch character used to introduce
options on command lines. For UNIX its value is `-', and
for MSDOS its value may be `/' or `-'. The macro is inter-
nally defined and is not user setable. The MSDOS version of
dmake attempts to first extract SWITCHAR from an environment
variable of the same name. If that fails it then attempts
to use the undocumented getswitchar system call, and returns
the result of that. Under MSDOS version 4.0 you must set
the value of the environment macro SWITCHAR to '/' to obtain
predictable behavior.
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DMAKE(p) Unsupported Free Software DMAKE(p)
All boolean macros currently understood by dmake correspond
directly to the previously defined attributes. These macros
provide a second way to apply global attributes, and
represent the preferred method of doing so. They are used
by assigning them a value. If the value is not a NULL
string then the boolean condition is set to on. If the
value is a NULL string then the condition is set to off.
There are five conditions defined and they correspond
directly to the attributes of the same name. Their meanings
are defined in the ATTRIBUTES section above. The macros
are: .EPILOG, .IGNORE, .MKSARGS, .NOINFER, .PRECIOUS, .PRO-
LOG, .SEQUENTIAL, .SILENT, .SWAP, and .USESHELL. Assigning
any of these a non NULL value will globally set the
corresponding attribute to on.
RUN_TIME MACROS
These macros are defined when dmake is making targets, and
may take on different values for each target. $@ is defined
to be the full target name, $? is the list of all out of
date prerequisites, $& is the list of all prerequisites, $>
is the name of the library if the current target is a
library member, and $< is the list of prerequisites speci-
fied in the current rule. If the current target had a
recipe inferred then $< is the name of the inferred prere-
quisite even if the target had a list of prerequisites sup-
plied using an explicit rule that did not provide a recipe.
In such situations $& gives the full list of prerequisites.
$* is defined as $(@:db) when making targets with explicit
recipes and is defined as the value of % when making targets
whose recipe is the result of an inference. In the first
case $* is the target name with no suffix, and in the second
case, is the value of the matched % pattern from the associ-
ated %-rule. $^ expands to the set of out of date prere-
quisites taken from the current value of $<. In addition to
these, $$ expands to $, {{ expands to {, }} expands to },
and the strings <+ and +> are recognized as respectively
starting and terminating a text diversion when they appear
literally together in the same input line.
The difference between $? and $^ can best be illustrated by
an example, consider:
fred.out : joe amy hello
rules for making fred
fred.out : my.c your.h his.h her.h # more prerequisites
Assume joe, amy, and my.c are newer then fred.out. When
dmake executes the recipe for making fred.out the values of
the following macros will be:
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DMAKE(p) Unsupported Free Software DMAKE(p)
$@ --> fred.out
$* --> fred
$? --> joe amy my.c # note the difference between $? and $^
$^ --> joe amy
$< --> joe amy hello
$& --> joe amy hello my.c your.h his.h her.h
FUNCTION MACROS
dmake supports a full set of functional macros. One of
these, the $(mktmp ...) macro, is discussed in detail in the
TEXT DIVERSION section and is not covered here.
$(null,text true false)
expands the value of text. If it is NULL then the
macro returns the value of the expansion of true
and the expansion of false otherwise. The terms
true, and false must be strings containing no
white-space.
$(!null,text true false)
Behaves identically to the previous macro except
that the true string is chosen if the expansion of
text is not NULL.
$(eq,text_a,text_b true false)
expands text_a and text_b and compares their
results. If equal it returns the result of the
expansion of the true term, otherwise it returns
the expansion of the false term.
$(!eq,text_a,text_b true false)
Behaves identically to the previous macro except
that the true string is chosen if the expansions
of the two strings are not equal
$(shell command)
Runs command as if it were part of a recipe and
returns, separated by a single space, all the
non-white space terms written to stdout by the
command. For example:
$(shell ls *.c)
will return "a.c b.c c.c d.c" if the files exist
in the current directory. The recipe modification
flags [+@%-] are honored if they appear as the
first characters in the command. For example:
$(shell +ls *.c)
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will run the command using the current shell.
$(sort list)
Will take all white-space separated tokens in list
and will return their sorted equivalent list.
$(strip data)
Will replace all strings of white-space in data by
a single space.
$(subst,pat,replacement data)
Will search for pat in data and will replace any
occurrence of pat with the replacement string.
The expansion
$(subst,.o,.c $(OBJECTS))
is equivalent to:
$(OBJECTS:s/.o/.c/)
DYNAMIC PREREQUISITES
dmake looks for prerequisites whose names contain macro
expansions during target processing. Any such prerequisites
are expanded and the result of the expansion is used as the
prerequisite name. As an example the line:
fred : $$@.c
causes the $$@ to be expanded when dmake is making fred, and
it resolves to the target fred. This enables dynamic prere-
quisites to be generated. The value of @ may be modified by
any of the valid macro modifiers. So you can say for exam-
ple:
fred.out : $$(@:b).c
where the $$(@:b) expands to fred. Note the use of $$
instead of $ to indicate the dynamic expansion, this is due
to the fact that the rule line is expanded when it is ini-
tially parsed, and $$ then returns $ which later triggers
the dynamic prerequisite expansion. If you really want a $
to be part of a prerequisite name you must use $$$$.
Dynamic macro expansion is performed in all user defined
rules, and the special targets .SOURCE*, and .INCLUDEDIRS.
BINDING TARGETS
This operation takes a target name and binds it to an exist-
ing file, if possible. dmake makes a distinction between
the internal target name of a target and its associated
external file name. Thus it is possible for a target's
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internal name and its external file name to differ. To per-
form the binding, the following set of rules is used.
Assume that we are trying to bind a target whose name is of
the form X.suff, where .suff is the suffix and X is the stem
portion (ie. that part which contains the directory and the
basename). dmake takes this target name and performs a
series of search operations that try to find a suitably
named file in the external file system. The search opera-
tion is user controlled via the settings of the various
.SOURCE targets.
1. If target has the .SYMBOL attribute set then look
for it in the library. If found, replace the tar-
get name with the library member name and continue
with step 2. If the name is not found then
return.
2. Extract the suffix portion (that following the
`.') of the target name. If the suffix is not
null, look up the special target .SOURCE.<suff>
(<suff> is the suffix). If the special target
exists then search each directory given in the
.SOURCE.<suff> prerequisite list for the target.
If the target's suffix was null (ie. .suff was
empty) then perform the above search but use the
special target .SOURCE.NULL instead. If at any
point a match is found then terminate the search.
If a directory in the prerequisite list is the
special name `.NULL ' perform a search for the
full target name without prepending any directory
portion (ie. prepend the NULL directory). (a
default target of '.SOURCE : .NULL' is defined by
dmake at startup, and is user redefinable)
3. The search in step 2. failed. Repeat the same
search but this time use the special target
.SOURCE.
4. The search in step 3. failed. If the target has
the library member attribute (.LIBMEMBER) set then
try to find the target in the library which was
passed along with the .LIBMEMBER attribute (see
the MAKING LIBRARIES section). The bound file
name assigned to a target which is successfully
located in a library is the same name that would
be assigned had the search failed (see 5.).
5. The search failed. Either the target was not
found in any of the search directories or no
applicable .SOURCE special targets exist. If
applicable .SOURCE special targets exist, but the
target was not found, then dmake assigns the first
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name searched as the bound file name. If no
applicable .SOURCE special targets exist, then the
full original target name becomes the bound file
name.
There is potential here for a lot of search operations. The
trick is to define .SOURCE.x special targets with short
search lists and leave .SOURCE as short as possible. The
search algorithm has the following useful side effect. When
a target having the .LIBMEMBER (library member) attribute is
searched for, it is first searched for as an ordinary file.
When a number of library members require updating it is
desirable to compile all of them first and to update the
library at the end in a single operation. If one of the
members does not compile and dmake stops, then the user may
fix the error and make again. dmake will not remake any of
the targets whose object files have already been generated
as long as none of their prerequisite files have been modi-
fied as a result of the fix.
When defining .SOURCE and .SOURCE.x targets the construct
.SOURCE :
.SOURCE : fred gery
is equivalent to
.SOURCE :- fred gery
dmake correctly handles the UNIX Make variable VPATH. By
definition VPATH contains a list of ':' separated direc-
tories to search when looking for a target. dmake maps
VPATH to the following special rule:
.SOURCE :^ $(VPATH:s/:/ /)
Which takes the value of VPATH and sets .SOURCE to the same
set of directories as specified in VPATH.
PERCENT(%) RULES AND MAKING INFERENCES
When dmake makes a target, the target's set of prerequisites
(if any) must exist and the target must have a recipe which
dmake can use to make it. If the makefile does not specify
an explicit recipe for the target then dmake uses special
rules to try to infer a recipe which it can use to make the
target. Previous versions of Make perform this task by
using rules that are defined by targets of the form
.<suffix>.<suffix> and by using the .SUFFIXES list of suf-
fixes. The exact workings of this mechanism were sometimes
difficult to understand and often limiting in their useful-
ness. Instead, dmake supports the concept of %-meta rules.
The syntax and semantics of these rules differ from standard
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rule lines as follows:
<%-target> [<attributes>] <ruleop> [<%-prerequisites>] [;<recipe>]
where %-target is a target containing exactly a single `%'
sign, attributes is a list (possibly empty) of attributes,
ruleop is the standard set of rule operators, %-prere-
quisites , if present, is a list of prerequisites containing
zero or more `%' signs, and recipe, if present, is the first
line of the recipe.
The %-target defines a pattern against which a target whose
recipe is being inferred gets matched. The pattern match
goes as follows: all chars are matched exactly from left to
right up to but not including the % sign in the pattern, %
then matches the longest string from the actual target name
not ending in the suffix given after the % sign in the pat-
tern. Consider the following examples:
%.c matches fred.c but not joe.c.Z
dir/%.c matches dir/fred.c but not dd/fred.c
fred/% matches fred/joe.c but not f/joe.c
% matches anything
In each case the part of the target name that matched the %
sign is retained and is substituted for any % signs in the
prerequisite list of the %-meta rule when the rule is
selected during inference and dmake constructs the new
dependency. As an example the following %-meta rules
describe the following:
%.c : %.y ; recipe...
describes how to make any file ending in .c if a correspond-
ing file ending in .y can be found.
foo%.o : fee%.k ; recipe...
is used to describe how to make fooxxxx.o from feexxxx.k.
%.a :; recipe...
describes how to make a file whose suffix is .a without
inferring any prerequisites.
%.c : %.y yaccsrc/%.y ; recipe...
is a short form for the construct:
%.c : %.y ; recipe...
%.c : yaccsrc/%.y ; recipe...
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ie. It is possible to specify the same recipe for two
%-rules by giving more than one prerequisite in the prere-
quisite list. A more interesting example is:
% : RCS/%,v ; co $<
which describes how to take any target and check it out of
the RCS directory if the corresponding file exists in the
RCS directory. The equivalent SCCS rule would be:
% : s.% ; get $<
The previous RCS example defines an infinite rule, because
it says how to make anything from RCS/%,v, and anything also
includes RCS/fred.c,v. To limit the size of the graph that
results from such rules dmake uses the macro variable PREP
(stands for % repetition). By default the value of this
variable is 0, which says that no repetitions of a %-rule
are to be generated. If it is set to something greater than
0, then that many repetitions of any infinite %-rule are
allowed. If in the above example PREP was set to 1, then
dmake would generate the dependency graph:
% --> RCS/%,v --> RCS/RCS/%,v,v
Where each link is assigned the same recipe as the first
link. PREP should be used only in special cases, since it
may result in a large increase in the number of possible
prerequisites tested. dmake further assumes that any target
that has no suffix can be made from a prerequisite that has
at least one suffix.
dmake supports dynamic prerequisite generation for prere-
quisites of %-meta rules. This is best illustrated by an
example. The RCS rule shown above can infer how to check
out a file from a corresponding RCS file only if the target
is a simple file name with no directory information. That
is, the above rule can infer how to find RCS/fred.c,v from
the target fred.c, but cannot infer how to find
srcdir/RCS/fred.c,v from srcdir/fred.c because the above
rule will cause dmake to look for RCS/srcdir/fred.c,v; which
does not exist (assume that srcdir has its own RCS directory
as is the common case).
A more versatile formulation of the above RCS check out rule
is the following:
% : $$(@:d)RCS/$$(@:f),v : co $@
This rule uses the dynamic macro $@ to specify the prere-
quisite to try to infer. During inference of this rule the
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macro $@ is set to the value of the target of the %-meta
rule and the appropriate prerequisite is generated by
extracting the directory portion of the target name (if
any), appending the string RCS/ to it, and appending the
target file name with a trailing ,v attached to the previous
result.
dmake can also infer indirect prerequisites. An inferred
target can have a list of prerequisites added that will not
show up in the value of $< but will show up in the value of
$? and $&. Indirect prerequisites are specified in an
inference rule by quoting the prerequisite with single
quotes. For example, if you had the explicit dependency:
fred.o : fred.c ; rule to make fred.o
fred.o : local.h
then this can be inferred for fred.o from the following
inference rule:
%.o : %.c 'local.h' ; rule to make a .o from a .c
You may infer indirect prerequisites that are a function of
the value of '%' in the current rule. The meta-rule:
%.o : %.c '$(INC)/%.h' ; rule to make a .o from a .c
infers an indirect prerequisite found in the INC directory
whose name is the same as the expansion of $(INC), and the
prerequisite name depends on the base name of the current
target. The set of indirect prerequisites is attached to
the meta rule in which they are specified and are inferred
only if the rule is used to infer a recipe for a target.
They do not play an active role in driving the inference
algorithm. The construct:
%.o : %.c %.f 'local.h'; recipe
is equivalent to:
%.o : %.c 'local.h' : recipe
%.o : %.f 'local.h' : recipe
If any of the attributes .SETDIR, .EPILOG, .PROLOG, .SILENT,
.USESHELL, .SWAP, .PRECIOUS, .LIBRARY, .NOSTATE and .IGNORE
are given for a %-rule then when that rule is bound to a
target as the result of an inference, the target's set of
attributes is augmented by the attributes from the above set
that are specified in the bound %-rule. Other attributes
specified for %-meta rules are not inherited by the target.
The .SETDIR attribute is treated in a special way. If the
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target already had a .SETDIR attribute set then dmake
changes to that directory prior to performing the inference.
During inference any .SETDIR attributes for the inferred
prerequisite are honored. The directories must exist for a
%-meta rule to be selected as a possible inference path. If
the directories do not exist no error message is issued,
instead the corresponding path in the inference graph is
rejected.
dmake also supports the old format special target
.<suffix>.<suffix> by identifying any rules of this form and
mapping them to the appropriate %-rule. So for example if
an old makefile contains the construct:
.c.o :; cc -c $< -o $@
dmake maps this into the following %-rule:
%.o : %.c; cc -c $< -o $@
Furthermore, dmake understands several SYSV AUGMAKE special
targets and maps them into corresponding %-meta rules.
These transformation must be enabled by providing the -A
flag on the command line or by setting the value of AUGMAKE
to non-NULL. The construct
.suff :; recipe
gets mapped into:
% : %.suff; recipe
and the construct
.c~.o :; recipe
gets mapped into:
%.o : s.%.c ; recipe
In general, a special target of the form .<str>~ is replaced
by the %-rule construct s.%.<str>, thereby providing support
for the syntax used by SYSV AUGMAKE for providing SCCS sup-
port. When enabled, these mappings allow processing of
existing SYSV makefiles without modifications.
dmake bases all of its inferences on the inference graph
constructed from the %-rules defined in the makefile. It
knows exactly which targets can be made from which prere-
quisites by making queries on the inference graph. For this
reason .SUFFIXES is not needed and is completely ignored.
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For a %-meta rule to be inferred as the rule whose recipe
will be used to make a target, the target's name must match
the %-target pattern, and any inferred %-prerequisite must
already exist or have an explicit recipe so that the prere-
quisite can be made. Without transitive closure on the
inference graph the above rule describes precisely when an
inference match terminates the search. If transitive clo-
sure is enabled (the usual case), and a prerequisite does
not exist or cannot be made, then dmake invokes the infer-
ence algorithm recursively on the prerequisite to see if
there is some way the prerequisite can be manufactured.
For, if the prerequisite can be made then the current target
can also be made using the current %-meta rule. This means
that there is no longer a need to give a rule for making a
.o from a .y if you have already given a rule for making a
.o from a .c and a .c from a .y. In such cases dmake can
infer how to make the .o from the .y via the intermediary .c
and will remove the .c when the .o is made. Transitive clo-
sure can be disabled by giving the -T switch on the command
line.
A word of caution. dmake bases its transitive closure on
the %-meta rule targets. When it performs transitive clo-
sure it infers how to make a target from a prerequisite by
performing a pattern match as if the potential prerequisite
were a new target. The set of rules:
%.o : %.c :; rule for making .o from .c
%.c : %.y :; rule for making .c from .y
% : RCS/%,v :; check out of RCS file
will, by performing transitive closure, allow dmake to infer
how to make a .o from a .y using a .c as an intermediate
temporary file. Additionally it will be able to infer how
to make a .y from an RCS file, as long as that RCS file is
in the RCS directory and has a name which ends in .y,v. The
transitivity computation is performed dynamically for each
target that does not have a recipe. This has potential to
be costly if the %-meta rules are not carefully specified.
The .NOINFER attribute is used to mark a %-meta node as
being a final target during inference. Any node with this
attribute set will not be used for subsequent inferences.
As an example the node RCS/%,v is marked as a final node
since we know that if the RCS file does not exist there
likely is no other way to make it. Thus the standard
startup makefile contains an entry similar to:
.NOINFER : RCS/%,v
Thereby indicating that the RCS file is the end of the
inference chain.
Whenever the inference algorithm determines that a target
can be made from more than one prerequisite and the
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inference chains for the two methods are the same length the
algorithm reports an ambiguity and prints the ambiguous
inference chains.
dmake tries to remove intermediate files resulting from
transitive closure if the file is not marked as being PRE-
CIOUS, or the -u flag was not given on the command line, and
if the inferred intermediate did not previously exist.
Intermediate targets that existed prior to being made are
never removed. This is in keeping with the philosophy that
dmake should never remove things from the file system that
it did not add. If the special target .REMOVE is defined
and has a recipe then dmake constructs a list of the inter-
mediate files to be removed and makes them prerequisites of
.REMOVE. It then makes .REMOVE thereby removing the prere-
quisites if the recipe of .REMOVE says to. Typically
.REMOVE is defined in the startup file as:
.REMOVE :; $(RM) $<
MAKING TARGETS
In order to update a target dmake must execute a recipe.
When a recipe needs to be executed it is first expanded so
that any macros in the recipe text are expanded, and it is
then either executed directly or passed to a shell. dmake
supports two types of recipes. The regular recipes and
group recipes.
When a regular recipe is invoked dmake executes each line of
the recipe separately using a new copy of a shell if a shell
is required. Thus effects of commands do not generally per-
sist across recipe lines. (e.g. cd requests in a recipe
line do not carry over to the next recipe line) The decision
on whether a shell is required to execute a command is based
on the value of the macro SHELLMETAS or on the specification
of '+' or .USESHELL for the current recipe or target respec-
tively. If any character in the value of SHELLMETAS is
found in the expanded recipe text-line or the use of a shell
is requested explicitly via '+' or .USESHELL then the com-
mand is executed using a shell, otherwise the command is
executed directly. The shell that is used for execution is
given by the value of the macro SHELL. The flags that are
passed to the shell are given by the value of SHELLFLAGS.
Thus dmake constructs the command line:
$(SHELL) $(SHELLFLAGS) $(expanded_recipe_command)
Normally dmake writes the command line that it is about to
invoke to standard output. If the .SILENT attribute is set
for the target or for the recipe line (via @), then the
recipe line is not echoed.
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Group recipe processing is similar to that of regular
recipes, except that a shell is always invoked. The shell
that is invoked is given by the value of the macro GROUP-
SHELL, and its flags are taken from the value of the macro
GROUPFLAGS. If a target has the .PROLOG attribute set then
dmake prepends to the shell script the recipe associated
with the special target .GROUPPROLOG, and if the attribute
.EPILOG is set as well, then the recipe associated with the
special target .GROUPEPILOG is appended to the script file.
This facility can be used to always prepend a common header
and common trailer to group recipes. Group recipes are
echoed to standard output just like standard recipes, but
are enclosed by lines beginning with [ and ].
The recipe flags [+,-,%,@] are recognized at the start of a
recipe line even if they appear in a macro. For example:
SH = +
all:
$(SH)echo hi
is completely equivalent to writing
SH = +
all:
+echo hi
The last step performed by dmake prior to running a recipe
is to set the macro CMNDNAME to the name of the command to
execute (determined by finding the first white-space ending
token in the command line). It then sets the macro CMNDARGS
to be the remainder of the line. dmake then expands the
macro COMMAND which by default is set to
COMMAND = $(CMNDNAME) $(CMNDARGS)
The result of this final expansion is the command that will
be executed. The reason for this expansion is to allow for
a different interface to the argument passing facilities
(esp. under DOS) than that provided by dmake. You can for
example define COMMAND to be
COMMAND = $(CMNDNAME) @$(mktmp $(CMNDARGS))
which dumps the arguments into a temporary file and runs the
command
$(CMNDNAME) @/tmp/ASAD23043
which has a much shorter argument list. It is now up to the
command to use the supplied argument as the source for all
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other arguments. As an optimization, if COMMAND is not
defined dmake does not perform the above expansion. On sys-
tems, such as UNIX, that handle long command lines this pro-
vides a slight saving in processing the makefiles.
MAKING LIBRARIES
Libraries are easy to maintain using dmake. A library is a
file containing a collection of object files. Thus to make
a library you simply specify it as a target with the
.LIBRARY attribute set and specify its list of prere-
quisites. The prerequisites should be the object members
that are to go into the library. When dmake makes the
library target it uses the .LIBRARY attribute to pass to the
prerequisites the .LIBMEMBER attribute and the name of the
library. This enables the file binding mechanism to look
for the member in the library if an appropriate object file
cannot be found. A small example best illustrates this.
mylib.a .LIBRARY : mem1.o mem2.o mem3.o
rules for making library...
# remember to remove .o's when lib is made
# equivalent to: '%.o : %.c ; ...'
.c.o :; rules for making .o from .c say
dmake will use the .c.o rule for making the library members
if appropriate .c files can be found using the search rules.
NOTE: this is not specific in any way to C programs, they
are simply used as an example.
dmake tries to handle the old library construct format in a
sensible way. The construct lib(member.o) is separated and
the lib portion is declared as a library target. The new
target is defined with the .LIBRARY attribute set and the
member.o portion of the construct is declared as a prere-
quisite of the lib target. If the construct lib(member.o)
appears as a prerequisite of a target in the makefile, that
target has the new name of the lib assigned as its prere-
quisite. Thus the following example:
a.out : ml.a(a.o) ml.a(b.o); $(CC) -o $@ $<
.c.o :; $(CC) -c $(CFLAGS) -o $@ $<
%.a:
ar rv $@ $?
ranlib $@
rm -rf $?
constructs the following dependency graph.
a.out : ml.a; $(CC) -o $@ $<
ml.a .LIBRARY : a.o b.o
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%.o : %.c ; $(CC) -c $(CFLAGS) -o $@ $<
%.a :
ar rv $@ $?
ranlib $@
rm -rf $?
and making a.out then works as expected.
The same thing happens for any target of the form
lib((entry)). These targets have an additional feature in
that the entry target has the .SYMBOL attribute set automat-
ically.
NOTE: If the notion of entry points is supported by the
archive and by dmake (currently not the case) then dmake
will search the archive for the entry point and return not
only the modification time of the member which defines the
entry but also the name of the member file. This name will
then replace entry and will be used for making the member
file. Once bound to an archive member the .SYMBOL attribute
is removed from the target. This feature is presently dis-
abled as there is little standardization among archive for-
mats, and we have yet to find a makefile utilizing this
feature (possibly due to the fact that it is unimplemented
in most versions of UNIX Make).
Finally, when dmake looks for a library member it must first
locate the library file. It does so by first looking for
the library relative to the current directory and if it is
not found it then looks relative to the current value of
$(TMD). This allows commonly used libraries to be kept near
the root of a source tree and to be easily found by dmake.
KEEP STATE
dmake supports the keeping of state information for targets
that it makes whenever the macro .KEEP_STATE is assigned a
value. The value of the macro should be the name of a state
file that will contain the state information. If state
keeping is enabled then each target that does not poses the
.NOSTATE attribute will have a record written into the state
file indicating the target's name, the current directory,
the command used to update the target, and which, if any, ::
rule is being used. When you make this target again if any
of this information does not match the previous settings and
the target is not out dated it will still be re-made. The
assumption is that one of the conditions above has changed
and that we wish to remake the target. For example, state
keeping is used in the maintenance of dmake to test compile
different versions of the source using different compilers.
Changing the compiler causes the compilation flags to be
modified and hence all sources to be recompiled.
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The state file is an ascii file and is portable, however it
is not in human readable form as the entries represent hash
keys of the above information.
The Sun Microsystem's Make construct
.KEEP_STATE :
is recognized and is mapped to .KEEP_STATE:=_state.mk. The
dmake version of state keeping does not include scanning C
source files for dependencies like Sun Make. This is
specific to C programs and it was felt that it does not
belong in make. dmake instead provides the tool, cdepend,
to scan C source files and to produce depedency information.
Users are free to modify cdepend to produce other dependency
files. (NOTE: cdepend does not come with the distribution
at this time, but will be available in a patch in the near
future)
MULTI PROCESSING
If the architecture supports it then dmake is capable of
making a target's prerequisites in parallel. dmake will
make as much in parallel as it can and use a number of child
processes up to the maximum specified by MAXPROCESS or by
the value supplied to the -P command line flag. A parallel
make is enabled by setting the value of MAXPROCESS (either
directly or via -P option) to a value which is > 1. dmake
guarantees that all dependencies as specified in the
makefile are honored. A target will not be made until all
of its prerequisites have been made. If a parallel make is
being performed then the following restrictions on parallel-
ism are enforced.
1. Individual recipe lines in a non-group recipe are
performed sequentially in the order in which they
are specified within the makefile and in parallel
with the recipes of other targets.
2. If a target contains multiple recipe definitions
(cf. :: rules) then these are performed sequen-
tially in the order in which the :: rules are
specified within the makefile and in parallel with
the recipes of other targets.
3. If a target rule contains the `!' modifier, then
the recipe is performed sequentially for the list
of outdated prerequisites and in parallel with the
recipes of other targets.
4. If a target has the .SEQUENTIAL attribute set then
all of its prerequisites are made sequentially
relative to one another (as if MAXPROCESS=1), but
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in parallel with other targets in the makefile.
Note: If you specify a parallel make then the order of tar-
get update and the order in which the associated recipes are
invoked will not correspond to that displayed by the -n
flag.
CONDITIONALS
dmake supports a makefile construct called a conditional.
It allows the user to conditionally select portions of
makefile text for input processing and to discard other por-
tions. This becomes useful for writing makefiles that are
intended to function for more than one target host and
environment. The conditional expression is specified as
follows:
.IF expression
... if text ...
.ELIF expression
... if text ...
.ELSE
... else text ...
.END
The .ELSE and .ELIF portions are optional, and the condi-
tionals may be nested (ie. the text may contain another
conditional). .IF, .ELSE, and .END may appear anywhere in
the makefile, but a single conditional expression may not
span multiple makefiles.
expression can be one of the following three forms:
<text> | <text> == <text> | <text> != <text>
where text is either text or a macro expression. In any
case, before the comparison is made, the expression is
expanded. The text portions are then selected and compared.
White space at the start and end of the text portion is dis-
carded before the comparison. This means that a macro that
evaluates to nothing but white space is considered a NULL
value for the purpose of the comparison. In the first case
the expression evaluates TRUE if the text is not NULL other-
wise it evaluates FALSE. The remaining two cases both
evaluate the expression on the basis of a string comparison.
If a macro expression needs to be equated to a NULL string
then compare it to the value of the macro $(NULL). You can
use the $(shell ...) macro to construct more complex test
expressions.
EXAMPLES
# A simple example showing how to use make
#
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prgm : a.o b.o
cc a.o b.o -o prgm
a.o : a.c g.h
cc a.c -o $@
b.o : b.c g.h
cc b.c -o $@
In the previous example prgm is remade only if a.o and/or
b.o is out of date with respect to prgm. These dependencies
can be stated more concisely by using the inference rules
defined in the standard startup file. The default rule for
making .o's from .c's looks something like this:
%.o : %.c; cc -c $(CFLAGS) -o $@ $<
Since there exists a rule (defined in the startup file) for
making .o's from .c's dmake will use that rule for manufac-
turing a .o from a .c and we can specify our dependencies
more concisely.
prgm : a.o b.o
cc -o prgm $<
a.o b.o : g.h
A more general way to say the above using the new macro
expansions would be:
SRC = a b
OBJ = {$(SRC)}.o
prgm : $(OBJ)
cc -o $@ $<
$(OBJ) : g.h
If we want to keep the objects in a separate directory,
called objdir, then we would write something like this.
SRC = a b
OBJ = {$(SRC)}.o
prgm : $(OBJ)
cc $< -o $@
$(OBJ) : g.h
%.o : %.c
$(CC) -c $(CFLAGS) -o $(@:f) $<
mv $(@:f) objdir
.SOURCE.o : objdir # tell make to look here for .o's
An example of building library members would go something
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like this: (NOTE: The same rules as above will be used to
produce .o's from .c's)
SRC = a b
LIB = lib
LIBm = { $(SRC) }.o
prgm: $(LIB)
cc -o $@ $(LIB)
$(LIB) .LIBRARY : $(LIBm)
ar rv $@ $<
rm $<
Finally, suppose that each of the source files in the previ-
ous example had the `:' character in their target name.
Then we would write the above example as:
SRC = f:a f:b
LIB = lib
LIBm = "{ $(SRC) }.o" # put quotes around each token
prgm: $(LIB)
cc -o $@ $(LIB)
$(LIB) .LIBRARY : $(LIBm)
ar rv $@ $<
rm $<
COMPATIBILITY
There are two notable differences between dmake and the
standard version of BSD UNIX 4.2/4.3 Make.
1. BSD UNIX 4.2/4.3 Make supports wild card filename
expansion for prerequisite names. Thus if a direc-
tory contains a.h, b.h and c.h, then a line like
target: *.h
will cause UNIX make to expand the *.h into "a.h b.h
c.h". dmake does not support this type of filename
expansion.
2. Unlike UNIX make, touching a library member causes
dmake to search the library for the member name and
to update the library time stamp. This is only
implemented in the UNIX version. MSDOS and other
versions may not have librarians that keep file time
stamps, as a result dmake touches the library file
itself, and prints a warning.
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dmake is not compatible with GNU Make. In particular it
does not understand GNU Make's macro expansions that query
the file system.
dmake is fully compatible with SYSV AUGMAKE, and supports
the following AUGMAKE features:
1. The word include appearing at the start of a line
can be used instead of the ".INCLUDE :" construct
understood by dmake.
2. The macro modifier expression $(macro:str=sub) is
understood and is equivalent to the expression
$(macro:s/str/sub), with the restriction that str
must match the following regular expression:
str[ |\t][ |\t]*
(ie. str only matches at the end of a token where
str is a suffix and is terminated by a space, a tab,
or end of line) Normally sub is expanded before the
substitution is made, if you specify -A on the com-
mand line then sub is not expanded.
3. The macro % is defined to be $@ (ie. $% expands to
the same value as $@).
4. The AUGMAKE notion of libraries is handled
correctly.
5. When defining special targets for the inference
rules and the AUGMAKE special target handling is
enabled then the special target .X is equivalent to
the %-rule "% : %.X".
6. Directories are always made if you specify -A. This
is consistent with other UNIX versions of Make.
7. Makefiles that utilize virtual targets to force mak-
ing of other targets work as expected if AUGMAKE
special target handling is enabled. For example:
FRC:
myprog.o : myprog.c $(FRC) ; ...
Works as expected if you issue the command
'dmake -A FRC=FRC'
but fails with a 'don't know how to make FRC' error
message if you do not specify AUGMAKE special target
handling via the -A flag (or by setting AUGMAKE:=yes
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internally).
LIMITS
In some environments the length of an argument string is
restricted. (e.g. MSDOS command line arguments cannot be
longer than 128 bytes if you are using the standard
command.com command interpreter as your shell, dmake text
diversions may help in these situations.)
PORTABILITY
To write makefiles that can be moved from one environment to
another requires some forethought. In particular you must
define as macros all those things that may be different in
the new environment. dmake has two facilities that help to
support writing portable makefiles, recursive macros and
conditional expressions. The recursive macros, allow one to
define environment configurations that allow different
environments for similar types of operating systems. For
example the same make script can be used for SYSV and BSD
but with different macro definitions.
To write a makefile that is portable between UNIX and MSDOS
requires both features since in almost all cases you will
need to define new recipes for making targets. The recipes
will probably be quite different since the capabilities of
the tools on each machine are different. Different macros
will be needed to help handle the smaller differences in the
two environments.
FILES
Makefile, makefile, startup.mk (use dmake -V to tell you
where the startup file is)
SEE ALSO
sh(1), csh(1), touch(1), f77(1), pc(1), cc(1)
S.I. Feldman Make - A Program for Maintaining Computer Pro-
grams
AUTHOR
Dennis Vadura, CS Dept. University of Waterloo.
dvadura@watdragon.uwaterloo.ca
Many thanks to Carl Seger for his helpful suggestions, and
to Trevor John Thompson for his many excellent ideas and
informative bug reports.
BUGS
Some system commands return non-zero status inappropriately.
Use -i (`-' within the makefile) to overcome the difficulty.
Some systems do not have easily accessible time stamps for
library members (MSDOS, AMIGA, etc) for these dmake uses the
time stamp of the library instead and prints a warning the
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first time it does so. This is almost always ok, except
when multiple makefiles update a single library file. In
these instances it is possible to miss an update if one is
not careful.
This man page is way too long.
WARNINGS
Rules supported by make(1) may not work if transitive clo-
sure is turned off (-T, .NOINFER).
PWD from csh/ksh will cause problems if a cd operation is
performed and -e or -E option is used.
Using internal macros such as COMMAND, may wreak havoc if
you don't understand their functionality.
If multiple MACRO=line arguments appear on the command line,
only the first is used. Beware of this in conjunction with
the MAKEMACROS variable.
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