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add documentation for long options and touch up the current docs now that i actually understand how to use the function myself :)

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This commit is contained in:
Mike Frysinger 2005-05-10 23:48:35 +00:00
parent 38a33f91c0
commit e5d0bde697
1 changed files with 62 additions and 39 deletions
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101
libbb/getopt_ulflags.c
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@ -28,6 +28,7 @@
/* Documentation !
unsigned long
bb_getopt_ulflags (int argc, char **argv, const char *applet_opts, ...)
The command line options must be declared in const char
@ -35,24 +36,25 @@ bb_getopt_ulflags (int argc, char **argv, const char *applet_opts, ...)
flags = bb_getopt_ulflags(argc, argv, "rnug");
If one of the given options is found a flag value is added to
the unsigned long returned by bb_getopt_ulflags.
If one of the given options is found, a flag value is added to
the return value (an unsigned long).
The value of this flag is given by the position of the char in
const char *applet_opts so for example in this case:
The flag value is determined by the position of the char in
applet_opts string. For example, in the above case:
flags = bb_getopt_ulflags(argc, argv, "rnug");
"r" will add 1
"n" will add 2
"u will add 4
"g" will add 8
"r" will add 1 (bit 1 : 0x01)
"n" will add 2 (bit 2 : 0x02)
"u will add 4 (bit 3 : 0x03)
"g" will add 8 (bit 4 : 0x04)
and so on.
and so on. You can also look at the return value as a bit
field and each option sets one of bits.
If an argument is required by one of the options add a ":"
after the char in const char *applet_opts and provide a pointer
where the arg could be stored if it is found, for example:
":" If one of the options requires an argument, then add a ":"
after the char in applet_opts and provide a pointer to store
the argument. For example:
char *pointer_to_arg_for_a;
char *pointer_to_arg_for_b;
@ -63,20 +65,43 @@ bb_getopt_ulflags (int argc, char **argv, const char *applet_opts, ...)
&pointer_to_arg_for_a, &pointer_to_arg_for_b,
&pointer_to_arg_for_c, &pointer_to_arg_for_d);
The type of the pointer (char* or llist_t *) can be influenced
by the "*" special character that can be set in const char
*bb_opt_complementaly (see below).
The type of the pointer (char* or llist_t *) may be controlled
by the "*" special character that is set in the external string
bb_opt_complementaly (see below for more info).
static const struct option bb_default_long_options[]
This struct allows you to define long options. The syntax for
declaring the array is just like that of getopt's longopts.
static const struct option applet_long_options[] = {
{ "verbose", 0, 0, "v" },
{ 0, 0, 0, 0 }
};
bb_applet_long_options = applet_long_options;
The first parameter is the long option that you would pass to
the applet (--verbose) in place of the short option (-v). The
second field determines whether the option has an argument.
You can set this to 0, 1, or 2, or you can use the long named
defines of no_argument, required_argument, and optional_argument.
Just set the third argument to '0' or 'NULL'. The last argument
is simply the short option without the dash of course.
Note: a good applet will make long options configurable via the
config process and not a required feature. The current standard
is to name the config option CONFIG_FEATURE_<applet>_LONG_OPTIONS.
const char *bb_opt_complementaly
":" The colon (":") is used in bb_opt_complementaly as separator
between groups of two or more chars and/or groups of chars and
special characters (stating some conditions to be checked).
":" The colon (":") is used to separate groups of two or more chars
and/or groups of chars and special characters (stating some
conditions to be checked).
"abc" If groups of two or more chars are specified the first char
is the main option and the other chars are secondary options
whose flags will be turned on if the main option is found even
if they are not specifed on the command line, for example:
"abc" If groups of two or more chars are specified, the first char
is the main option and the other chars are secondary options.
Their flags will be turned on if the main option is found even
if they are not specifed on the command line. For example:
bb_opt_complementaly = "abc";
@ -92,30 +117,28 @@ Special characters:
to be unset (and ignored) if it is given on the command line.
For example:
The du applet can have the options "-s" and "-d depth", if
bb_getopt_ulflags finds -s then -d is unset or if it finds -d
The du applet has the options "-s" and "-d depth". If
bb_getopt_ulflags finds -s, then -d is unset or if it finds -d
then -s is unset. (Note: busybox implements the GNU
"--max-depth" option as "-d".) In this case bb_getopt_ulflags's
return value has no error flag set (0x80000000UL). To achieve
this result you must set bb_opt_complementaly = "s-d:d-s".
Only one flag value is added to bb_getopt_ulflags's return
value depending on the position of the options on the command
line. If one of the two options requires an argument pointer
(":" in const char *applet_opts as in "d:") optarg is set
accordingly.
"--max-depth" option as "-d".) To obtain this behavior, you
set bb_opt_complementaly = "s-d:d-s". Only one flag value is
added to bb_getopt_ulflags's return value depending on the
position of the options on the command line. If one of the
two options requires an argument pointer (":" in applet_opts
as in "d:") optarg is set accordingly.
char *smax_print_depth;
bb_opt_complementaly = "s-d:d-s";
opt = bb_getopt_ulflags(argc, argv, "sd:" , &smax_print_depth);
opt = bb_getopt_ulflags(argc, argv, "sd:", &smax_print_depth);
if (opt & 2) {
max_print_depth = bb_xgetularg10_bnd(smax_print_depth,
0, INT_MAX);
}
"~" A tilde between two options or between an option and a group
of options means that they are mutually exclusive. Unlike
"~" A tilde between two options, or between an option and a group
of options, means that they are mutually exclusive. Unlike
the "-" case above, an error will be forced if the options
are used together.
@ -128,7 +151,7 @@ Special characters:
return value will have the error flag set (0x80000000UL) so
that we can check for it:
if ((flags & 0x80000000UL)
if (flags & 0x80000000UL)
bb_show_usage();
"*" A star after a char in bb_opt_complementaly means that the
@ -138,15 +161,15 @@ Special characters:
The grep applet can have one or more "-e pattern" arguments.
In this case you should use bb_getopt_ulflags() as follows:
llist_t *patterns=NULL;
llist_t *patterns = NULL;
(this pointer must be initializated to NULL if the list is empty
as required by *llist_add_to(llist_t *old_head, char *new_item).)
bb_opt_complementaly = "e*";
bb_getopt_ulflags (argc, argv, "e:", &patterns);
grep -e user -e root /etc/passwd
bb_getopt_ulflags(argc, argv, "e:", &patterns);
$ grep -e user -e root /etc/passwd
root:x:0:0:root:/root:/bin/bash
user:x:500:500::/home/user:/bin/bash