gno/doc/refs.aug96/man4.html

1968 lines
74 KiB
HTML
Raw Normal View History

1997-10-07 01:43:55 +00:00
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
<html>
<head>
<meta http-equiv="Content-Type"
content="text/html; charset=iso-8859-1">
<meta name="GENERATOR" content="Microsoft FrontPage 2.0">
<title>NAME</title>
</head>
<body bgcolor="#FFFFFF">
<hr>
<p><b>NAME</b></p>
<dir>
<li>truncate, ftruncate - set a file to a specified length</li>
</dir>
<p><b>SYNOPSIS</b></p>
<dir>
<li>#include &lt;sys/types.h&gt;<p>int <b>truncate</b>(char *<i>path</i>,
off_t <i>length</i>)</p>
<p>int <b>ftruncate</b>(int <i>fd</i>, off_t <i>length</i>)</p>
</li>
</dir>
<p><b>DESCRIPTION</b></p>
<dir>
<li><b>truncate</b>() causes the file referred to by <i>path</i>
(or for <b>ftruncate</b>() the object referred to by <i>fd</i>
) to have a size equal to length bytes. If the file was
previously longer than length , the extra bytes are
removed from the file. If it was shorter, bytes between
the old and new lengths are read as zeroes. With <b>ftruncate</b>(),
the file must be open for writing.</li>
</dir>
<p><b>RETURN VALUES</b></p>
<dir>
<li><b>truncate</b>() returns:<p>0 on success.</p>
<p>-1 on failure and sets <b>errno</b> to indicate the
error.</p>
</li>
</dir>
<p><b>ERRORS</b></p>
<dir>
<li><b>truncate</b>() may set <b>errno</b> to:<p><font
face="Courier New">EACCES</font> Search permission is
denied for a component of the path prefix of <i>path</i>.</p>
<p>Write permission is denied for the file referred to by
<i>path</i> .</p>
<p><font face="Courier New">EIO</font> An I/O error
occurred while reading from or writing to the file
system.</p>
<p><font face="Courier New">EISDIR</font> The file
referred to by <i>path</i> is a directory.</p>
<p><font face="Courier New">ENAMETOOLONG</font> The
length of the <i>path</i> argument exceeds {<font
face="Courier New">PATH_MAX</font>}.</p>
<p>A pathname component is longer than {<font
face="Courier New">NAME_MAX</font>} (see <b>sysconf</b>
(2V)) while {<font face="Courier New">_POSIX_NO_TRUNC</font>}
is in effect (see pathconf (2V)).</p>
<p><font face="Courier New">ENOENT</font> The file
referred to by <i>path</i> does not exist.</p>
<p><font face="Courier New">ENOTDIR</font> A component of
the path prefix of <i>path</i> is not a directory.</p>
<p><font face="Courier New">EROFS</font> The file
referred to by <i>path</i> resides on a read-only file
system.</p>
<p><b>ftruncate</b>() may set <b>errno</b> to:</p>
<p><font face="Courier New">EINVAL</font> <i>fd</i> is
not a valid descriptor of a file open for writing.</p>
<p><i>fd</i> refers to a socket, not to a file.</p>
<p><font face="Courier New">EIO</font> An I/O error
occurred while reading from or writing to the file
system.</p>
</li>
</dir>
<p><b>SEE ALSO</b></p>
<dir>
<li><b>open</b> (2)</li>
</dir>
<p><b>BUGS</b></p>
<dir>
<li>These calls should be generalized to allow ranges of
bytes in a file to be discarded.</li>
</dir>
<hr>
<p><b>NAME</b></p>
<dir>
<li>wait, WIFSTOPPED, WIFSIGNALED, WIFEXITED - wait for
process to terminate or stop</li>
</dir>
<p><b>SYNOPSIS</b></p>
<dir>
<li>#include &lt;sys/wait.h&gt;<p>int <b>wait</b>(union wait
*<i>statusp</i>);</p>
<p><b>WIFSTOPPED</b>(union wait <i>status</i>);</p>
<p><b>WIFSIGNALED</b>(union wait <i>status</i>);</p>
<p><b>WIFEXITED</b>(union wait <i>status</i>);</p>
</li>
</dir>
<p><b>DESCRIPTION</b></p>
<dir>
<li><b>wait</b> blocks the caller until a signal is received
or one of its child processes terminates. If any child
has died and this has not been reported using wait,
return is immediate, returning the process ID and exit
status of one of those children. If that child had died,
it is discarded. If there are no children, return is
immediate with the value -1 returned. If there are
processes that have not been reported by wait, the caller
is blocked.<p>If <i>status</i> is not a NULL pointer,
then on return from a successful <b>wait</b> call the
status of the child process whose process ID is the
return value of wait is stored in the <font
face="Courier New">wait union</font> pointed to by
status. The wstatus member of that union is an int; it
indicates the cause of termination and other information
about the terminated process in the following manner:</p>
<p>&#149; If the low-order 8 bits of <i>wstatus</i> are
equal to 0177 (hex 0xFF), the child process has stopped;
the high-order 8 bits of <i>wstatus</i> contain the
number of the signal that caused the process to stop. See
<b>signal</b>(2).</p>
<p>&#149; If the low-order 8 bits of <i>wstatus</i> are
non-zero and are not equal to 0177, the child process
terminated due to a signal; the low-order 7 bits of <i>wstatus</i>
contain the number of the signal that terminated the
process.</p>
<p>&#149; Otherwise, the child process terminated due to
an <b>exit</b>() call; the high-order 8 bits of wstatus
contain the low-order 8 bits of the argument that the
child process passed to <b>exit</b> or GS/OS Quit.</p>
<p>Other members of the <font face="Courier New">wait
union</font> can be used to extract this information more
conveniently:</p>
<p>&#149; If the <font face="Courier New">wstopval</font>
member has the value <font face="Courier New">WSTOPPED</font>,
the child process has stopped; the value of the <font
face="Courier New">wstopsig</font> member is the signal
that stopped the process.</p>
<p>&#149; If the <font face="Courier New">wtermsig</font>
member is non-zero, the child process terminated due to a
signal; the value of the <font face="Courier New">wtermsig</font>
member is the number of the signal that terminated the
process. </p>
<p>&#149; Otherwise, the child process terminated due to
an <b>exit</b>() call; the value of the <font
face="Courier New">wretcode</font> member is the
low-order 8 bits of the argument that the child process
passed to <b>exit</b>().</p>
<p>The other members of the <font face="Courier New">wait
union</font> merely provide an alternate way of analyzing
the status. The value stored in the <font
face="Courier New">wstatus</font> field is compatible
with the values stored by versions of the UNIX system,
and an argument of type<font face="Courier New"> int *</font>
may be provided instead of an argument of type <font
face="Courier New">union wait *</font> for compatibility
with those versions.</p>
<p><b>WIFSTOPPED</b>, <b>WIFSIGNALED</b>, <b>WIFEXITED</b>,
are macros that take an argument <i>status</i>, of type `<font
face="Courier New">union wait</font>', as returned by <b>wait</b>().
<b>WIFSTOPPED</b> evaluates to true (1) when the process
for which the <b>wait</b> call was made is stopped, or to
false (0) otherwise. <b>WIFSIGNALED</b> evaluates to true
when the process was terminated with a signal. <b>WIFEXITED</b>
evaluates to true when the process exited by using an <b>exit</b>(2)
call.</p>
<p>If <b>wait</b> returns due to a stopped or terminated
child process, the process ID of the child is returned to
the calling process. Otherwise, a value of -1 is returned
and <b>errno</b> is set to indicate the error.</p>
</li>
</dir>
<p><b>ERRORS</b></p>
<dir>
<li>wait will fail and return immediately if one or more of
the following are true:<p><font face="Courier New">[ECHILD]</font>
The calling process has no existing unwaited-for child
processes.</p>
<p><font face="Courier New">[EFAULT]</font> The status or
rusage arguments point to an illegal address.</p>
<p><font face="Courier New">[EINTR]</font> The wait call
was interrupted by a caught signal.</p>
</li>
</dir>
<p><b>SEE ALSO</b></p>
<dir>
<li><b>signal</b>(2), <b>exit</b>(3), <b>rexit</b>(3), <b>execve</b>(2)</li>
</dir>
<p><b>NOTES</b></p>
<dir>
<li>If a parent process terminates without waiting on its
children, the Kernel Null Process (process ID = 0)
inherits the children.<p><b>wait</b> is automatically
restarted when a process receives a signal while awaiting
termination of a child process, if the signal is not
caught; i.e. <b>signal</b>() handler value is SIG_DFL or
SIG_IGN.</p>
</li>
</dir>
<p><font size="2" face="Courier">GSString255Ptr <b>__C2GSMALLOC</b>(char
*<i>s</i>)</font></p>
<p><font face="Times">Converts a C-style string to a Class 1
GS/OS string, allocating space for the GS/OS string from C's
malloc() routine. You must specifically deallocate the string
with free() when you're through with it.</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">char *<b>__GS2CMALLOC</b>(GSString255Ptr
<i>g</i>)</font></p>
<p><font face="Times">Converts a Class 1 GS/OS string to a
C-style string, allocating space for the C string from C's
malloc() routine. You must specifically deallocate the string
with free() when you're through with it.</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">char *<b>__GS2C</b>(char *<i>s</i>,
GSString255Ptr <i>g</i>)</font></p>
<p><font face="Times">Converts a Class 1 GS/OS string to a C
string; the buffer space for the C string must be allocated
beforehand by the caller. The return value is the address of the
C string passed as argument s.</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">int <b>_mapErr</b>(int <i>err</i>)</font></p>
<p><font face="Times">Tries to map a GS/OS error code (err) to a
UNIX errno code (return value). If there is no direct mapping,
EIO is returned.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>access</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;unistd.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>access</b>(char *<i>name</i>,
int <i>mode</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Returns TRUE (1) if the file specified by <i>name</i>
can be acessed according to <i>mode</i> by the calling process.
Values of mode are declared in &lt;unistd.h&gt; and are as
follows:</font></p>
<dir>
<li><font face="Times">F_OK - returns true if the file exists</font><p><font
face="Times">X_OK - returns true if the process has
execution permissions for the file</font></p>
<p><font face="Times">W_OK - returns true if the process
has write permissions for the file</font></p>
<p><font face="Times">R_OK - returns true if the process
has read permissions for the file</font></p>
</li>
</dir>
<p><font face="Times"><b>bcopy bzero</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;string.h&gt;</font></p>
<p><font size="2" face="Courier">void <b>bcopy</b>(char *<i>b1</i>,
char *<i>b2</i>, size_t <i>n</i>)</font></p>
<p><font size="2" face="Courier">void <b>bzero</b>(char *<i>buf</i>,
size_t <i>n</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>bcopy</b>() copies <i>n</i> bytes from
memory address <i>b1</i> to memory address <i>b2</i>. <b>bcopy</b>()
is functionally similar to <b>memcpy</b>(), except that bcopy
copies from the first argument to the second argument, whereas <b>memcpy</b>()
copies from the second argument to the first argument. If the
memory areas overlap, the results are unpredictable. <b>bcopy</b>()
is provided for compatibility with BSD source code.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>bzero</b>() clears n bytes of memory
starting at <i>buf</i> to 0 (zero). This call is functionally
equivalent to <b>memset</b>(buf,0,n) and is included for BSD
source code compatibilty.</font></p>
<p><font face="Times">See Also: <b>memcpy</b>, <b>memset</b>, <i>ORCA/C
2.0 Manual</i></font></p>
<p>&nbsp;</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
<p>&nbsp;</p>
<p><font face="Times"><b>chdir</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;unistd.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>chdir</b>(const char *<i>pathname</i>)</font></p>
<p><font face="Times">Changes the current working directory
(GS/OS prefix 0) to the pathname specified by <i>pathname</i>. If
an error occurs changing the prefix, -1 is returned and the error
code is placed in <b>errno</b>.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>crypt</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">char *<b>crypt</b>(char *<i>pw</i>,char
*<i>salt</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>crypt</b> is used to encrypt passwords
for storage in the /etc/passwd file, and also to validate
passwords entered in the login and passwd programs. <i>pw</i> is
the password to encrypt, a NUL- terminated string. <i>salt</i> is
a two- character encryption key that should be randomly generated
by the caller in the case of encrypting a new password, or should
be taken as the first two characters of the /etc/passwd password
entry in the case of validating a password.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>crypt</b> returns a pointer to the
encrypted password, which is formatted as printable ASCII
characters and is NUL terminated. A static buffer is used to hold
the result, so to be sure the encrypted password is not
overwritten by a subsequent call to <b>crypt</b> copy it before
use.</font></p>
<p><font face="Times">See also: <b>getpass</b>, <b>getpwent</b></font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>errno strerror perror</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">char *<b>strerror</b>(int <i>errnum</i>)</font></p>
<p><font size="2" face="Courier">void <b>perror</b>(char *<i>s</i>)</font></p>
<p><font size="2" face="Courier">extern int <b>errno</b>;</font></p>
<p>&nbsp;</p>
<p><font face="Times">These routines are as documented in the
ORCA/C manual, except that they support the full range of GNO's
errno codes. <b>errno</b> is the variable that most library and
kernel calls place their return status in. The codes are defined
symbolically in &lt;errno.h&gt; and are listed here:</font></p>
<p><font face="Times">EDOM domain error</font></p>
<p><font face="Times">ERANGE number too large, too small, or
illegal</font></p>
<p><font face="Times">ENOMEM Not enough memory</font></p>
<p><font face="Times">ENOENT No such file or directory</font></p>
<p><font face="Times">EIO I/O error</font></p>
<p><font face="Times">EINVAL Invalid argument</font></p>
<p><font face="Times">EBADF bad file descriptor</font></p>
<p><font face="Times">EMFILE too many files are open</font></p>
<p><font face="Times">EACCESS access bits prevent the operation</font></p>
<p><font face="Times">EEXIST the file exists</font></p>
<p><font face="Times">ENOSPC the file is too large</font></p>
<p><font face="Times">EPERM Not owner</font></p>
<p><font face="Times">ESRCH No such process</font></p>
<p><font face="Times">EINTR Interrupted system call</font></p>
<p><font face="Times">E2BIG Arg list too long</font></p>
<p><font face="Times">ENOEXEC Exec format error</font></p>
<p><font face="Times">ECHILD No children</font></p>
<p><font face="Times">EAGAIN No more processes</font></p>
<p><font face="Times">ENOTDIR Not a directory</font></p>
<p><font face="Times">ENOTTY Not a terminal</font></p>
<p><font face="Times">EPIPE Broken pipe</font></p>
<p><font face="Times">ESPIPE Illegal seek</font></p>
<p><font face="Times">ENOTBLK not a block device</font></p>
<p><font face="Times">EISDIR not a plain file</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>fsync</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">int <b>fsync</b>(int <i>fd</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Causes the operating system to flush any
I/O buffers associated with the file referenced by file
descriptor fd to disk. This ensures that all information is up to
date, in the event of a system crash. This call is only needed in
special circumstances, as when several daemon processes are all
modifying the same file simultaneously (currently impossible with
existing IIGS filesystems). This call is basically a <b>FlushGS</b>.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>ftruncate</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">int <b>ftruncate</b>(int <i>fd</i>,
off_t <i>length</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Causes the EOF marker for the file
specified by file descriptor <i>fd</i> to be set to length. In
the event of an error, ftruncate returns -1 and sets errno.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getgrnam getgrgid getgrent setgrent
setgroupent endgrent</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;sys/types.h&gt;</font></p>
<p><font size="2" face="Courier">#include &lt;grp.h&gt;</font></p>
<p><font size="2" face="Courier">struct group *<b>getgrnam</b>(const
char *<i>name</i>);</font></p>
<p><font size="2" face="Courier">struct group *<b>getgrgid</b>(gid_t
<i>gid</i>);</font></p>
<p><font size="2" face="Courier">struct group *<b>getgrent</b>(void);</font></p>
<p><font size="2" face="Courier">int <b>setgrent</b>(void);</font></p>
<p><font size="2" face="Courier">int <b>setgroupent</b>(int <i>stayopen</i>);</font></p>
<p><font size="2" face="Courier">void <b>endgrent</b>(void);</font></p>
<p><font face="Times">(POSIX)</font></p>
<p>&nbsp;</p>
<p><font face="Times">This family of functions should be used to
access the groups database; applications should never read
/etc/groups directly, as the implementation of the groups
database is subject to change.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getgrnam</b>() reads the group database
based on group name. It looks up the supplied group name and
returns a pointer to a struct group (see below), or NULL on an
error.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getgrgid</b>() is similar to <b>getgrnam</b>(),
except that instead of looking up group information based on
group name, a group ID is passed.</font></p>
<p>&nbsp;</p>
<p><font face="Times">To scan the groups database linearly, start
the scan with either <b>setgrent</b>() or <b>setgroupent</b>().
The two functions are identical for pure scanning operations, but
have different behavior when mixing scan calls with <b>getgrnam</b>()
or <b>getgrgid</b>().</font></p>
<p>&nbsp;</p>
<p><font face="Times">After calling <b>setgrent</b> or <b>setgroupent</b>,
the scan is set to the first entry in the database. <b>getgrent</b>
returns a pointer to the current entry and moves the scan to the
next entry. In the event of an error, <b>getgrent</b> returns
NULL. When the program is done with the database, <b>endgrent</b>
should be called.</font></p>
<p>&nbsp;</p>
<p><font face="Times">If <b>getgrnam</b> or <b>getgrgid</b> is
called while scanning the group database, the database will be
closed unless it was opened by calling setgroupent with an
argument of 1. This indicates &quot;keep open&quot; mode, and
allows fast random access of the database with the <b>getgrnam</b>
and getgrgid functions (which would otherwise open and close the
database for every call).</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getopt getopt_restart</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;getopt.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>getopt</b>(int <i>argc</i>,
char * const *<i>argv</i>, const char *<i>optstring</i>)</font></p>
<p><font size="2" face="Courier">int <b>getopt_restart</b>(void)</font></p>
<p><font size="2" face="Courier">extern char *<b>optarg</b>;</font></p>
<p><font size="2" face="Courier">extern int <b>optind</b>;</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>Getopt</b> helps parse command line
options as are often used by UNIX utilities. It handles simple
flags (such as &quot;ls -l&quot;) and also flags with arguments
(&quot;cc -o prog prog.c&quot;).</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>Getopt</b> returns the next option
letter in argv that matches a letter in optstring. <i>Optstring</i>
is a string of recognized option letters; if a letter is followed
by a colon, the option is expected to have an argument that may
or may not be separated from it by white space. <b>Optarg</b> is
set to point to the start of the option argument on return from
getopt.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>Getopt</b> places in <b>optind</b> the
argv index of the next argument to be processed. Because <b>optind</b>
is external, it is normally initialized to zero automatically
before the first call to <b>getopt</b>.</font></p>
<p>&nbsp;</p>
<p><font face="Times">When all options have been processed (i.e.,
up to the first non-option argument), getopt returns EOF. The
special option -- may be used to delimit the end of the options;
EOF will be returned, and -- will be skipped.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>Getopt</b> prints an error message on
stderr and returns a question mark (?) when it encounters an
option letter not included in <i>optstring</i>.</font></p>
<p>&nbsp;</p>
<p><font face="Times">The following code fragment shows how one
might process the arguments for a command that can take the
mutually exclusive options a and b, and the options f and o, both
of which require arguments:</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">main(int argc, char **argv)</font></p>
<p><font size="2" face="Courier">{</font></p>
<p><font size="2" face="Courier">int c;</font></p>
<p><font size="2" face="Courier">extern int optind;</font></p>
<p><font size="2" face="Courier">extern char *optarg;</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">while ((c = getopt(argc, argv,
&quot;abf:o:&quot;)) != EOF)</font></p>
<p><font size="2" face="Courier">switch (c) {</font></p>
<p><font size="2" face="Courier">case `a':</font></p>
<p><font size="2" face="Courier">if (bflg)</font></p>
<p><font size="2" face="Courier">errflg++;</font></p>
<p><font size="2" face="Courier">else</font></p>
<p><font size="2" face="Courier">aflg++;</font></p>
<p><font size="2" face="Courier">break;</font></p>
<p><font size="2" face="Courier">case `b':</font></p>
<p><font size="2" face="Courier">if (aflg)</font></p>
<p><font size="2" face="Courier">errflg++;</font></p>
<p><font size="2" face="Courier">else</font></p>
<p><font size="2" face="Courier">bproc();</font></p>
<p><font size="2" face="Courier">break;</font></p>
<p><font size="2" face="Courier">case `f':</font></p>
<p><font size="2" face="Courier">ifile = optarg;</font></p>
<p><font size="2" face="Courier">break;</font></p>
<p><font size="2" face="Courier">case `o':</font></p>
<p><font size="2" face="Courier">ofile = optarg;</font></p>
<p><font size="2" face="Courier">break;</font></p>
<p><font size="2" face="Courier">case `?':</font></p>
<p><font size="2" face="Courier">default:</font></p>
<p><font size="2" face="Courier">errflg++;</font></p>
<p><font size="2" face="Courier">break;</font></p>
<p><font size="2" face="Courier">}</font></p>
<p><font size="2" face="Courier">if (errflg) {</font></p>
<p><font size="2" face="Courier">fprintf(stderr, &quot;Usage:
...&quot;);</font></p>
<p><font size="2" face="Courier">exit(2);</font></p>
<p><font size="2" face="Courier">}</font></p>
<p><font size="2" face="Courier">for (; optind &lt; argc;
optind++) {</font></p>
<p><font size="2" face="Courier">.</font></p>
<p><font size="2" face="Courier">}</font></p>
<p><font size="2" face="Courier">.</font></p>
<p><font size="2" face="Courier">}</font></p>
<p>&nbsp;</p>
<p><font face="Times">It is not obvious how `-' standing alone
should be treated; this version treats it as a non-option
argument, which is not always right. Option arguments are allowed
to begin with `-'; this is reasonable but reduces the amount of
error checking possible.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getopt_restart</b> should be used in
restartable programs, before the first call to <b>getopt</b>, to
reinitialize the <b>optind</b> and <b>optarg</b> variables.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getpass</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">char *<b>getpass</b>(const char
*<i>prompt</i>)</font></p>
<p><font face="Times">BSD</font></p>
<p>&nbsp;</p>
<p><font face="Times">Prompts the user for a password, and
returns a pointer to a NUL-terminated string which contains the
password the user typed. A password may be up to 8 characters
long, and if the string the user</font></p>
<p><font face="Times">types is longer than that the returned
string is truncated to 8 characters. Argument <i>prompt</i> is
the string to print before requesting input. Input characters are
obscured - that is, not echoed - as the user types them. The
backspace and delete keys may be used to edit input, although in
practice this is difficult to use because the user cannot see
what he types.</font></p>
<p>&nbsp;</p>
<p><font face="Times">A static buffer is used to to hold the
password, so to be sure the password is not overwritten by a
subsequent call to getpass, copy it before use.</font></p>
<p><font face="Times">See also: <b>crypt</b>, <b>getpwent</b></font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getpwnam getpwuid endpwent setpwent</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;pwd.h&gt;</font></p>
<p><font size="2" face="Courier">struct passwd *<b>getpwnam</b>(const
char *<i>name</i>);</font></p>
<p><font size="2" face="Courier">struct passwd *<b>getpwuid</b>(uid_t
<i>uid</i>);</font></p>
<p><font size="2" face="Courier">void <b>endpwent</b>(void);</font></p>
<p><font size="2" face="Courier">struct passwd *<b>getpwent</b>(void);</font></p>
<p><font size="2" face="Courier">int <b>setpwent</b>(void);</font></p>
<p>&nbsp;</p>
<p><font face="Times">The family of functions defined in
&lt;pwd.h&gt; are used for accessing the /etc/passwd user
database. Programs should never access this database directly, as
the file format or other implementation details may change in the
future.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getpwnam</b>() reads the user database
based on user name. The argument <i>name</i> is a pointer to the
user name to lookup. <b>getpwnam</b>() returns a pointer to a
passwd structure or NULL on an error.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getpwuid</b>() reads the user database
based on a user ID code. Argument <i>uid</i> is the user ID to
return information on. <b>getpwuid</b>() returns a pointer to a
passwd structure or NULL on an error.</font></p>
<p>&nbsp;</p>
<p><font face="Times">The remaining three functions are used for
scanning the user database. The database is initialized by using
the <b>setpwent</b>() function; an internal access marker is set
to the first entry in the database.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getpwent</b>() is used to retrieve the
current entry, returning a pointer to a passwd structure, and
moving the marker to the next entry. If there are no more entries
to scan, <b>getpwent</b>() returns a NULL pointer. If the
database should be scanned again, <b>setpwent</b>() may be called
again to reset the marker to the first entry. In the event of an
error accessing the database, NULL is returned.</font></p>
<p>&nbsp;</p>
<p><font face="Times">When the application is through with the
database, it should call endpwent().</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">struct passwd { /* see
getpwent(3) */</font></p>
<p><font size="2" face="Courier">char *pw_name; /* pointer to
user name */</font></p>
<p><font size="2" face="Courier">char *pw_passwd; /* pointer to
encrypted password */</font></p>
<p><font size="2" face="Courier">int pw_uid; /* user ID */</font></p>
<p><font size="2" face="Courier">int pw_gid; /* group ID */</font></p>
<p><font size="2" face="Courier">int pw_quota; /* 'quota' field -
not used */</font></p>
<p><font size="2" face="Courier">char *pw_comment; /* pointer
Comment field */</font></p>
<p><font size="2" face="Courier">char *pw_gecos; /* not used */</font></p>
<p><font size="2" face="Courier">char *pw_dir; /* pointer to
user's '$home' directory name */</font></p>
<p><font size="2" face="Courier">char *pw_shell; /* pointer to
path of user's login shell */</font></p>
<p><font size="2" face="Courier">};</font></p>
<p>&nbsp;</p>
<p><font face="Times">Not all of the string entries in struct
passwd are used in GNO/ME, but those that are are all NUL-
terminated strings.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>getwd</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;unistd.h&gt;</font></p>
<p><font size="2" face="Courier">char *<b>getwd</b>(char *<i>pathname</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Gets the current working directory (GS/OS
prefix 0) and copies it to the string space pointed to by <i>pathname</i>.
<i>pathname</i> must point to a buffer large enough to hold the
largest conceivable pathname. In practice, a 256 byte buffer
works well, but with the plethora of GS/OS file systems now
available 256 may be much too small. Due to this problem, we
recommend you use <b>getwd</b> carefully, and with a future GNO
release switch to getcwd (not yet available).</font></p>
<p><font face="Times">If an error occurs during the operation, <b>getwd</b>
returns NULL and places the error code in <b>errno</b>.
Otherwise, <b>getwd</b> returns the prefix in <i>pathname</i>.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>gtty stty</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;sgtty.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>gtty</b>(int <i>filedes</i>,
struct sgttyb *<i>argp</i>)</font></p>
<p><font size="2" face="Courier">int <b>stty</b>(int <i>filedes</i>,
struct sgttyb *<i>argp</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Set and get TTY status information in the
sgttyb structures pointed to by the argument argp. See <b>ioctl</b>(2)
and <b>tty</b>(4) for more details. These routines are basically
short-cuts to </font></p>
<p><font face="Times">ioctl(filedes, TIOCSETP, &amp;structure)
and ioctl(filedes, TIOCGETP, &amp;structure).</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>index rindex</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">char *<b>index</b>(char *<i>a</i>,
int <i>b</i>)</font></p>
<p><font size="2" face="Courier">char *<b>rindex</b>(char *<i>a</i>,
int <i>b</i>)</font></p>
<p><font face="Times">(BSD)</font></p>
<p>&nbsp;</p>
<p><font face="Times">These functions are identical to <b>strchr</b>()
and <b>strrchr</b>(), respectively. See your C compiler manual
for more information. These functions are provided only for
compatibility with BSD source code.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>isatty</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;sgtty.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>isatty</b>(int <i>filedes</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">This function returns true (1) if the file
descriptor refers to a TTY (this includes PTYs) file. For all
other types of descriptors, false (0) is returned.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>login</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;utmp.h&gt;</font></p>
<p><font size="2" face="Courier">void <b>login</b>(struct utmp *<i>ut</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Writes the /etc/utmp structure pointed to
by ut to the utmp file. The slot in /etc/utmp actually written to
depends on the return value of the <b>ttyslot</b>() function,
which maps each tty device to a unique slot number, based on the
contents of /etc/ttys.</font></p>
<p>&nbsp;</p>
<p><font face="Times">This function should not generally be used
by application code.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>mkdir</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">int <b>mkdir</b>(char *<i>dirname</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Creates a subdirectory (folder) with the
name specified by dirname. Similar to the shell <b>'mkdir'</b>
command.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>mktemp mkstemp</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">char *<b>mktemp</b>(char *<i>path</i>)</font></p>
<p><font size="2" face="Courier">int <b>mkstemp</b>(char *<i>path</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Creates a filename based on the string path
that is guaranteed to be unique. The string path must have the
following format:</font></p>
<p>&nbsp;</p>
<p><font face="Times">&quot;/volume/dir1/.../dirX/fileXXXXXX&quot;
(Colons are also accepted as delimiters)</font></p>
<p>&nbsp;</p>
<p><font face="Times">The 'XXXXX' at the end of path is filler
space that will be replaced with a string that will make path a
unique filename.</font></p>
<p>&nbsp;</p>
<p><font face="Times">The unique string is generated by using the
current process ID and a single character ASCII value; this may
change in the future, and as such this behavior should not be
relied upon.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>mktemp</b>() does not actually create
any files, as compared with <b>tmpfile</b>() in the C library.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>mkstemp</b>() does create a file by
calling <b>open</b>() on a unique pathname generated with <b>mktemp</b>().</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>mktemp</b>() returns a pointer to the
new pathname (<i>path</i>), and <b>mkstemp</b>() returns a file
descriptor to the new file, as would be returned by <b>open</b>().</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>open creat close read write lseek</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;fcntl.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>creat</b>(const char *<i>path</i>,
int <i>mode</i>)</font></p>
<p><font size="2" face="Courier">int <b>open</b>(const char *<i>path</i>,
int <i>oflag</i>, ...)</font></p>
<p><font size="2" face="Courier">int <b>close</b>(int <i>filds</i>)</font></p>
<p><font size="2" face="Courier">int <b>read</b>(int <i>filds</i>,
void *<i>buf</i>, size_t <i>count</i>)</font></p>
<p><font size="2" face="Courier">int <b>write</b>(int <i>filds</i>,
void *<i>buf</i>, size_t <i>count</i>)</font></p>
<p><font size="2" face="Courier">long <b>lseek</b>(int <i>filds</i>,
long <i>offset</i>, int <i>whence</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">These are similar to the low-level I/O
routines provided by ORCA/C. However, the GNO versions of these
routines deal with actual GS/OS refNums for filds. (ORCA/C's
versions use a special library-maintained definition of file
descriptor in order to fake the UNIX <b>dup</b>() system call.
Here they revert to standard UNIX usage because GNO provides a
real <b>dup</b>(2) handled within the kernel).</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>open</b>() uses vararg (variable
argument) parameters. The third parameter is only expected (and
is required) if O_CREAT is one of the flags specified in '<i>mode</i>',
and specifies the access permissions to be given the new file.</font></p>
<p>&nbsp;</p>
<p><font face="Times">IMPORTANT NOTE: GNO's <b>read</b>()/<b>write</b>()
functions take a size_t count, whereas ORCA's only take unsigned
count. When recompiling code with the new GNO libraries, make
very certain that any programs that use <b>read</b>()/<b>write</b>()
do a #include &lt;fcntl.h&gt;, or it is likely that your programs
will crash.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>opendir readdir rewinddir closedir</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;dirent.h&gt;</font></p>
<p><font size="2" face="Courier">DIR *<b>opendir</b>(char *<i>filename</i>)</font></p>
<p><font size="2" face="Courier">struct <b>dirent</b>
*readdir(DIR *<i>dirp</i>)</font></p>
<p><font size="2" face="Courier">void <b>rewinddir</b>(DIR *<i>dirp</i>)</font></p>
<p><font size="2" face="Courier"><b>closedir</b>(DIR *<i>dirp</i>)</font></p>
<p><font face="Times">(POSIX 1)</font></p>
<p>&nbsp;</p>
<p><font face="Times">This family of functions provides a
machine-independent way to read a list of files (and information
about them) from directories.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>opendir</b>() opens the directory
specified by filename and prepares it for the scan operation. <b>opendir</b>()
returns a pointer to a structure which is used in the other
dirent calls.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>readdir</b>() takes a DIR * as argument
and returns information about the next file in the directory. The
return value is a pointer to a dirent structure (described
below).</font></p>
<p>&nbsp;</p>
<p><font face="Times">If you wish to scan the directory again
without closing and then reopening the directory, use <b>rewinddir</b>().
It resets the scan to the beginning of the directory.</font></p>
<p>&nbsp;</p>
<p><font face="Times">When finished with the directory, call <b>closedir</b>().</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#define MAXNAMLEN 32 /* maximum
filename length */</font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">struct dirent /* data from
getdents()/readdir() */</font></p>
<p><font size="2" face="Courier">{</font></p>
<p><font size="2" face="Courier">long d_ino; /* inode number of
entry */</font></p>
<p><font size="2" face="Courier">off_t d_off; /* offset of disk
directory entry */</font></p>
<p><font size="2" face="Courier">unsigned short d_reclen; /*
length of this record */</font></p>
<p><font size="2" face="Courier">char d_name[MAXNAMLEN]; /* name
of file */</font></p>
<p><font size="2" face="Courier">unsigned short d_namlen; /*
length of filename */</font></p>
<p><font size="2" face="Courier">};</font></p>
<p>&nbsp;</p>
<p><font face="Times">dirent is the structure returned by <b>readdir</b>()
that contains information about the file. <b>d_ino</b> is not
used on the Apple IIGS because neither ProDOS nor HFS have the
concept of an &quot;inode&quot;, but to simulate its use a unique
d_ino value is returned for each <b>readdir</b>() call. <b>d_off</b>
is the offset in the directory of the current file; the first
entry is number 1, the second 2, etc. <b>d_reclen</b> specifies
the length of the entire dirent structure. <b>d_name</b> is a
short array containing the filename of the current file read from
the directory. d_namlen is the length of the string in <b>d_name</b>.</font></p>
<p>&nbsp;</p>
<p><font face="Times">More specific information can be obtained
by passing <b>d_name</b> to the <b>stat</b>() system call.</font></p>
<p><font face="Times">See also: <b>stat</b>(2)</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>needsgno</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">int <b>needsgno</b>(void)</font></p>
<p>&nbsp;</p>
<p><font face="Times">This function returns 1 if GNO is
operating, and 0 if it is not. Use this function to abort
programs that use GNO-specific features, or to allow them to
enable non-GNO environment dependent code.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>parsearg</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier"><b>~GNO_PARSEARG</b> subroutine
(4:<i>commandline</i>,4:<i>argptr</i>)</font></p>
<p><font size="2" face="Courier"><b>~GNO_PARSEARG</b>(char *<i>commandline</i>,
char **<i>argptr</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">This function will take the command-line
passed to a utility and parse it into an argv,argc structure like
those used in C programs. This was written NOT as a replacement
for a C parser, but for use by assembly language programmers
writing shell commands.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><i>commandline</i> is the raw command line
string as passed by the shell in the X &amp; Y registers. <i>argptr</i>
is a pointer to an argv[]-style array. parsearg returns the
number of arguments found in the accumulator.</font></p>
<p>&nbsp;</p>
<p><font face="Times">This function ASSUMES that the ByteWorks
Memory Manager has been started up and is usable.</font></p>
<p>&nbsp;</p>
<p><font face="Times">This function is based on actual GNO/ME
shell (gsh) parsing code.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>pcreate pbind pgetport psend preceive
pdelete preset pgetcount</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;sys/ports.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>pcreate</b>(int <i>count</i>)</font></p>
<p><font size="2" face="Courier">int <b>pbind</b>(int <i>portid</i>,
char *<i>name</i>)</font></p>
<p><font size="2" face="Courier">int <b>pgetport</b>(char *<i>name</i>)</font></p>
<p><font size="2" face="Courier">int <b>psend</b>(int <i>portid</i>,
long int <i>msg</i>)</font></p>
<p><font size="2" face="Courier">long <b>preceive</b>(int <i>portid</i>)</font></p>
<p><font size="2" face="Courier">int <b>pdelete</b>(int <i>portid</i>,
int (*<i>dispose</i>)())</font></p>
<p><font size="2" face="Courier">int <b>preset</b>(int <i>portid</i>,
int (*<i>dispose</i>)())</font></p>
<p><font size="2" face="Courier">int <b>pgetcount</b>(int <i>portid</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">The Ports IPC mechanism is a very flexible,
powerful and efficient method of interprocess communication. A
port is a queue that can contain a number of 32-bit values. The
size of the port (how many messages it can contain) is specified
in the <b>pcreate</b>() call.</font></p>
<p>&nbsp;</p>
<p><font face="Times">Creation of a port is done with <b>pcreate</b>().
You must specify the size of the port in this call, which must be
at least 1 (one). The larger the port, the more data it can hold
without blocking a process sending data to the port. <b>pcreate</b>()
returns a port ID value that must be used in subsequent calls to
the Port IPC routines.</font></p>
<p>&nbsp;</p>
<p><font face="Times">A name may be associated with a port; this
allows totally unrelated processes to access a port without
having to communicate the port ID through some other method, and
without knowing the process ID of the other. To bind a name to a
port, call <b>pbind</b>(). The name argument may be any length,
but at most 32 characters are significant. If a name has already
been bound to the chosen portid, an error is returned. To get the
portid of a port by its name, use the <b>pgetport</b>() call.
Pass in the name of the port whose port ID you wish to obtain. If
no port has that name, an error is returned. Names are only
unbound from a port when a port is deleted.</font></p>
<p>&nbsp;</p>
<p><font face="Times">psend() is used to send a 32-bit datum to a
port. If the port is full (that is, if there are more unread
messages in the port than are specified in the <b>pcreate</b>()
call) then the sending process blocks until a message is read
from the port. Messages are retrieved from a port using the <b>preceive</b>()
call. pgetcount() returns the number of messages in the port that
have not been received; this may be used to avoid blocking on a <b>psend</b>()
call.</font></p>
<p>&nbsp;</p>
<p><font face="Times">If you wish to clear the contents of a
port, say to synchronize communication after an error condition,
use the <b>preset</b>() call. The arguments to this call are the
port ID and the address of a <i>'dispose'</i> function. Each
message in the port, before being cleared, is passed to the
dispose function so that appropriate clean-up action may be taken
on the data. For example, if the messages correspond to the
address of memory blocks obtained with <b>malloc</b>(), you could
pass <b>'free</b>()' as the dispose function to automatically
deallocate that memory. If you don't wish to take any special
action on the data being cleared, pass NULL for the dispose
argument.</font></p>
<p>&nbsp;</p>
<p><font face="Times">To destroy a port, make the <b>pdelete</b>()
call. It accepts the same arguments as <b>preset</b>() and they
operate as described above. The difference between <b>preset</b>()
and <b>pdelete</b>() is that the latter totally destroys a port;
it may no longer be used. <b>preset</b>() clears a port's data
but leaves the port open for more data transmission.</font></p>
<p>&nbsp;</p>
<p><font face="Times">For an example of the use of ports, see the
source code to the print spooling utilities (<b>lpr</b>, <b>lpd</b>,
<b>FilePort</b>). These are available from Procyon upon request.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>regexp</b></font></p>
<p>&nbsp;</p>
<p><font face="Times">Compile and execute regular-expression
programs. Use 'man regexp' for details.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>send receive recvtim recvclr</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;gno/gno.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>send</b>(int pid,
unsigned long <i>msg</i>);</font></p>
<p><font size="2" face="Courier">unsigned long <b>receive</b>(void);</font></p>
<p><font size="2" face="Courier">unsigned long <b>recvtim</b>(int
<i>timeout</i>);</font></p>
<p><font size="2" face="Courier">unsigned long <b>recvclr</b>(void);</font></p>
<p>&nbsp;</p>
<p><font face="Times">These kernel functions comprise GNO's
message-passing IPC system. Messages are unsigned 32-bit data
values. A process sends a message to another by using the <b>send</b>()
call. You must specify the process ID of the recipient and the
message to pass. To receive a message, a process makes the <b>receive</b>()
call. If no message has been sent to the process, the process
sleeps until a message arrives. recvclr() is used to clear any
pending message a process may have waiting. <b>recvtim</b>() is
similar to <b>receive</b>() but takes a timeout argument,
specified in 1/10ths of a second. If no message has been received
in <i>timeout</i>/10 seconds, <b>recvtim</b>() fails and returns
-1. The message buffer for a process is only one message deep;
any attempt to <b>send</b>() a message to a process that already
has one queued results in an error. For an IPC system with a
deeper queue, see the Ports IPC section.</font></p>
<p>&nbsp;</p>
<p><font face="Times">A <b>receive</b>() that is interrupted by a
signal will abort and return -1, with errno set to EINTR.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>setenv unsetenv</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;unistd.h&gt;</font></p>
<p><font size="2" face="Courier">int <b>setenv</b>(const char *<i>name</i>,
const char *<i>value</i>, int <i>rewrite</i>)</font></p>
<p><font size="2" face="Courier">void <b>unsetenv</b>(const char
*<i>name</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Set the value of the environmental variable
name to be value. If <i>rewrite</i> is set, <b>setenv</b>
replaces any current value. The variable is considered
'exported', according to the shell convention for variables. No
errors are possible, and the only return code is 0.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>unsetenv</b> removes the environmental
variable specified by name from the variable table. The variable
is no longer accessible, and any value that was assigned to that
variable is deallocated. No errors are possible, and there is no
return value.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>statfs</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">int <b>statfs</b>(char *<i>path</i>,
struct statfs *<i>buf</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Returns information on the filesystem that
the file <i>path</i> resides on. The information is placed in a
structure pointed to by the input argument <i>buf</i>. Read <b>statfs</b>(3)
for more information.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>strdup</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;string.h&gt;</font></p>
<p><font size="2" face="Courier">char *<b>strdup</b>(const char *<i>str</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>strdup</b>() creates a copy of the
NUL-terminated string pointed to by <i>str</i>. It allocates a
piece of memory exactly large enough to hold the string with the <b>malloc</b>()
library function. When you no longer need the copy, dispose of it
with <b>free</b>().</font></p>
<p><font face="Times">See also: <b>strcpy</b>(), <b>malloc</b>(),
<b>free</b>()</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>strsep</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;string.h&gt;</font></p>
<p><font size="2" face="Courier">char *<b>strsep</b>(char **<i>stringp</i>,
const char *<i>delim</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Gets a token from string *<i>stringp</i>,
where tokens are nonempty strings separated by characters from
delim.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>strsep</b> writes NULs into *<i>stringp</i>
to end tokens. <i>delim</i> need not remain constant from call to
call. On return, *<i>stringp</i> points past the last NUL written
(if there might be further tokens), or is NULL (if there are
definitely no more tokens). If *<i>stringp</i> is NULL, <i>strsep</i>
returns NULL.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>termcap</b></font></p>
<p>&nbsp;</p>
<p><font face="Times">The termcap library accesses the
/etc/termcap database, which is used to provide terminal-
independent support for advanced terminal features, such as
various text modes, scrolling regions, cursor movement, and more.
Use 'man termcap' for more details.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>ttyname</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">#include &lt;unistd.h&gt;</font></p>
<p><font size="2" face="Courier">char *<b>ttyname</b>(int <i>fd</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Returns the filename of the tty referenced
by file descriptor <i>fd</i>. If fd does not refer to a tty file,
NULL is returned. Otherwise, a pointer to the filename
(NUL-terminated string) is returned.</font></p>
<p>&nbsp;</p>
<p><font face="Times">tty filenames are in the format
&quot;.ttyXX&quot;, where XX is a device designator. When porting
existing BSD code, take care to watch for code that depends on
the existence of a '/' character in the string, as UNIX tty files
are in the form &quot;/dev/ttyXX&quot;.</font></p>
<p>&nbsp;</p>
<p><font face="Times">The string pointer returned points to a
static buffer, and will be overwritten on any further calls to <b>ttyname</b>.
Copy the string if you wish to preserve it.</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b>unlink</b></font></p>
<p>&nbsp;</p>
<p><font size="2" face="Courier">int <b>unlink</b>(char *<i>fname</i>)</font></p>
<p>&nbsp;</p>
<p><font face="Times">Causes the link file specified by <i>fname</i>
to be removed. Since GNO/ME does not yet support symbolic or hard
file links, this function operates the same as the <b>remove</b>()
(or DestroyGS) routine.</font></p>
<hr>
<p><font face="Times"><b>NAME</b></font></p>
<dir>
<li><font face="Times">tty - general terminal interface</font></li>
</dir>
<p><font face="Times"><b>SYNOPSIS</b></font></p>
<dir>
<li><font face="Times">#include &lt;sgtty.h&gt;</font></li>
</dir>
<p><font face="Times"><b>DESCRIPTION</b></font></p>
<dir>
<li><font face="Times">This file documents the special file </font><font
face="Courier">.tty</font><font face="Times"> and the
terminal drivers used for user-oriented I/O.</font></li>
</dir>
<p><font face="Times"><b>The Controlling Terminal</b></font></p>
<dir>
<li><font face="Times">Every process has associated with it a
controlling terminal, which is the terminal the process
was invoked from. In some versions of Unix, the
controlling terminal association is responsible for job
control; this is not so under GNO. A process' controlling
terminal is inherited from its parent. By opening the
special file .tty, a process can access its controlling
terminal. This is useful where the input and output of a
process was redirected and the process wants to be sure
of outputting or getting input from the user at the
terminal.</font><p><font face="Times">A process can
remove the association it has with its controlling
terminal by opening the file .tty and issuing an</font></p>
<p><font face="Times">ioctl(f, TIOCNOTTY, 0);</font></p>
<p><font face="Times">This is often desirable in server
processes.</font></p>
</li>
</dir>
<p><font face="Times"><b>Process Groups</b></font></p>
<dir>
<li><font face="Times">Every terminal has an associated
process group. Any time a signal-generating special
character is typed at the terminal, the terminal's
process group is sent that signal. Unix systems set
process groups using ioctl() calls, but under GNO a new
interface method is used; process group assignments are
controlled with the JOB CONTROL(2) routines.</font></li>
</dir>
<p><font face="Times"><b>Modes</b></font></p>
<dir>
<li><font face="Times">There are four modes in which terminal
drivers operate. These modes control how the driver deals
with I/O.</font><p><font face="Times"><i>cooked</i> This
is the default mode of the terminal driver. If an
incoming character is one of the special characters
defined in sgttyb, tchars, or ltchars, the appropriate
action is performed (see below). This mode also allows
for input editing, as input is internally buffered line
by line, and data is returned to a reading process only
when CR is entered.</font></p>
<p><font face="Times"><i>cbreak</i> Input is returned on
a per-character basis, instead of line by line as in
cooked mode. If no data is available, a read will block
the calling process. If data is available, a number of
characters up to but not exceeding the requested number
will be returned. Special characters such as t_intrc are
not handled, but are passed on to the caller as data.</font></p>
<p><font face="Times"><i>raw</i> Like cbreak mode, except
that no input or output processing whatsoever is
performed.</font></p>
</li>
</dir>
<p><font face="Times"><b>Summary of terminal control modes</b></font></p>
<p>&nbsp;</p>
<dir>
<li><font face="Times">Due to the colorful history of Unix
systems, the data structures used to manipulate terminal
modes and settings are separated into four groups. Future
revisions of GNO will implement the POSIX termio
interface, which consolidates these structures into one
place.</font></li>
</dir>
<p><font face="Times"><b>sgtty</b></font></p>
<dir>
<li><font face="Times">The basic ioctls use the structure
defined in &lt;sgtty.h&gt;:</font><p><font size="2"
face="Courier">struct sgttyb {</font></p>
<p><font size="2" face="Courier">char sg_ispeed;</font></p>
<p><font size="2" face="Courier">char sg_ospeed;</font></p>
<p><font size="2" face="Courier">char sg_erase;</font></p>
<p><font size="2" face="Courier">char sg_kill;</font></p>
<p><font size="2" face="Courier">short sg_flags;</font></p>
<p><font size="2" face="Courier">};</font></p>
<p><font face="Times">sg_ispeed and sg_ospeed indicate
the baud rates for input and output according to the
following table. Speed changes that do not apply to a
particular piece of hardware are ignored (for instance,
the console driver does not access a serial port so all
baud rate settings are, in effect, impossible). Also, not
all the baud rates supported by a particular device are
allowed to be set from this interface. </font></p>
<p><font face="Times">These symbolic names for the baud
rate settings are defined in &lt;sgtty.h&gt;.</font></p>
<p><font face="Times">B0 0 (hang up dataphone)</font></p>
<p><font face="Times">B50 1 50 baud</font></p>
<p><font face="Times">B75 2 75 baud</font></p>
<p><font face="Times">B110 3 110 baud</font></p>
<p><font face="Times">B134 4 134.5 baud</font></p>
<p><font face="Times">B150 5 150 baud</font></p>
<p><font face="Times">B300 7 300 baud</font></p>
<p><font face="Times">B600 8 600 baud</font></p>
<p><font face="Times">B1200 9 1200 baud</font></p>
<p><font face="Times">B1800 10 1800 baud</font></p>
<p><font face="Times">B2400 11 2400 baud</font></p>
<p><font face="Times">B4800 12 4800 baud</font></p>
<p><font face="Times">B9600 13 9600 baud</font></p>
<p><font face="Times">B19200 and</font></p>
<p><font face="Times">EXTA 14 19200 baud</font></p>
<p><font face="Times">B38400 and</font></p>
<p><font face="Times">EXTB 15 38400 baud</font></p>
<p><font face="Times">B57600 6 57600 baud</font></p>
<p><font face="Times">The sg_erase and sg_kill fields
specify the line-editing erase and kill characters.
sg_erase is 0x7F (delete) by default, and sg_kill is not
currently used.</font></p>
<p><font face="Times">sg_flags is a bitmapped value that
indicates various state settings for the terminal driver
(values are in hex).</font></p>
<p><font face="Times">EVENP 0x80 Use Even parity (serial
devices only)</font></p>
<p><font face="Times">ODDP 0x40 Use Odd parity (serial
devices only)</font></p>
<p><font face="Times">RAW 0x20 Raw mode: wake up on all
characters, 8-bit interface</font></p>
<p><font face="Times">CRMOD 0x10 Map CR into LF; output
LF as CR-LF</font></p>
<p><font face="Times">ECHO 0x08 Echo (full duplex)</font></p>
<p><font face="Times">CBREAK 0x02 Return each character
as soon as typed</font></p>
<p><font face="Times">TANDEM 0x01 Automatic flow control</font></p>
<p><font face="Times"><b>RAW</b> and <b>CBREAK</b> modes
were described above, in Modes.</font></p>
<p><font face="Times">If the <b>CRMOD</b> bit is set, a
line feed character is appended to any echoed or ouputted
carriage return.</font></p>
<p><font face="Times">The <b>ECHO</b> bit controls input
echoing; if enabled, any characters read from the
terminal are echoed. This behavior differs slightly from
Unix, where input characters are echoed as soon as typed.</font></p>
<p><font face="Times"><b>TANDEM</b> mode enables
automatic software flow control utilizing the special
characters t_startc and t_stopc in tchars (below).
Whenever the input queue is in danger of overflowing, the
system sends t_stopc; when the queue has drained
sufficiently, t_startc is sent. This mode has no effect
on the console driver.</font></p>
<p><font face="Times">Note: t_startc and t_stopc are used
for both directions of flow control; when t_stopc is
received from a remote system (or user), the terminal
stops output, and when t_startc is received output
resumes. Certain drivers may also require t_stopc and
t_startc to be the same character, in which case one or
the other setting will be ignored. See the driver's
documentation for details.</font></p>
<p><font face="Times">Basic Ioctls</font></p>
<p><font face="Times">Most <b>ioctl</b>() calls apply to
terminals. They have the form</font></p>
<p><font face="Times">#include &lt;sgtty.h&gt;</font></p>
<p><font face="Times">ioctl(int filedes, unsigned long
code, void *arg)</font></p>
<p><font face="Times">arg is usually a pointer to a
structure or int. The ioctl codes that apply to sgtty
are:</font></p>
<p><font face="Courier"><b>TIOCGETP</b></font><font
face="Times"> Fetch the basic parameters associated with
the terminal, and store in the sgttyb structure pointed
to by arg.</font></p>
<p><font face="Courier"><b>TIOCSETP</b></font><font
face="Times"> Set the terminal's basic parameters
according to the sgttyb structure pointed to by arg. The
input queue is flushed, and the call waits for the output
queue to drain before the parameters are changed.</font></p>
<p><font face="Courier"><b>TIOCSETN</b></font><font
face="Times"> This is like TIOCSETP, except there is no
delay and the input queue is not flushed.</font></p>
<p><font face="Times">With the following codes arg is
ignored.</font></p>
<p><font face="Courier"><b>TIOCEXCL</b></font><font
face="Times"> Set &quot;exclusive-use&quot; mode. The
terminal may not be opened again by any process until all
existing references are closed.</font></p>
<p><font face="Courier"><b>TIOCNXCL </b></font><font
face="Times">Turns off &quot;exclusive-use&quot; mode.</font></p>
<p><font face="Courier"><b>TIOCHPCL</b></font><font
face="Times"> When the last reference to the terminal is
closed, the terminal line is forced to hang up. This
applies only to modem drivers.</font></p>
<p><font face="Times">With the following codes, arg is a
pointer to an int.</font></p>
<p><font face="Courier"><b>TIOCGETD</b></font><font
face="Times"> The current line discipline number is
stored in the int pointed to by arg. This value is
currently ignored.</font></p>
<p><font face="Courier"><b>TIOCSETD</b></font><font
face="Times"> The line discipline is set according to the
int pointed to by arg.</font></p>
<p><font face="Courier"><b>TIOCFLUSH</b></font><font
face="Times"> The specified queue is flushed. If the
value pointed to by arg is zero, both the input and
output queues are flushed. If the value is FREAD (defined
in &lt;sys/file.h&gt;), the input queue is flushed. If
the value is FWRITE, the output queue is flushed.</font></p>
<p><font face="Times">The last few calls permit detailed
control of the driver. In cases where an argument is
required, it is described. Otherwise, arg should be a
NULL pointer.</font></p>
<p><font face="Courier"><b>TIOCSTI</b></font><font
face="Times"> The character pointed to by the argument is
placed in the input queue as if it had been typed on the
terminal.</font></p>
<p><font face="Courier"><b>TIOCSBRK</b></font><font
face="Times"> Begins a break sequence on the terminal.</font></p>
<p><font face="Courier"><b>TIOCCBRK</b></font><font
face="Times"> Ends a break sequence.</font></p>
<p><font face="Courier"><b>TIOCSDTR</b></font><font
face="Times"> The DTR line is turned on</font></p>
<p><font face="Courier"><b>TIOCCDTR</b></font><font
face="Times"> The DTR line is turned off</font></p>
<p><font face="Courier"><b>TIOCSTOP</b></font><font
face="Times"> Output is stopped as if t_stopc had been
typed on the terminal.</font></p>
<p><font face="Courier"><b>TIOCSTART</b></font><font
face="Times"> If output is stopped, it is resumed as if
t_startc had been typed on the terminal.</font></p>
<p><font face="Courier"><b>TIOCOUTQ</b></font><font
face="Times"> The number of characters in the output
queue is returned in the int pointed to by arg.</font></p>
<p><font face="Courier"><b>FIONREAD</b></font><font
face="Times"> The number of characters immediately
available for input from the terminal is returned in the
int pointed to by arg. This is the preferred method of
non-blocking I/O (checking for the presence of characters
without waiting for them).</font></p>
</li>
</dir>
<p><font face="Times"><b>Tchars</b></font></p>
<dir>
<li><font face="Times">The second structure associated with a
terminal defines special characters. The structure is
defined in &lt;sys/ioctl.h&gt; which is automatically
included by &lt;sgtty.h&gt;.</font><p><font face="Times">struct
tchars {</font></p>
<p><font face="Times">char t_intrc; /* interrupt */</font></p>
<p><font face="Times">char t_quitc; /* quit */</font></p>
<p><font face="Times">char t_startc; /* start output */</font></p>
<p><font face="Times">char t_stopc; /* stop output */</font></p>
<p><font face="Times">char t_eofc; /* end-of-file */</font></p>
<p><font face="Times">char t_brkc; /* input delimiter
(like nl) */</font></p>
<p><font face="Times">};</font></p>
<p><font face="Times">The default values for these
characters are ^C, ^\, ^Q, ^S, ^D and -1 respectively. A
value of -1 for any of the characters means that the
effect of that character is ignored. The stop and start
characters may be the same to produce a 'toggle' effect.
It is not recommended to set any of the other characters
to the same values; the order in which the special
characters are checked is not defined, and the results
you get may not be what was expected.</font></p>
<p><font face="Times">The ioctl calls that apply to
tchars are:</font></p>
<p><font face="Courier"><b>TIOCGETC</b></font><font
face="Times"> Returns the special characters settings in
the tchars structure pointed to by arg.</font></p>
<p><font face="Courier"><b>TIOCSETC</b></font><font
face="Times"> The special characters are set according to
the given structure.</font></p>
</li>
</dir>
<p><font face="Times"><b>Local mode</b></font></p>
<p>&nbsp;</p>
<dir>
<li><font face="Times">The third structure in the terminal
interface is a local mode word. The various bitfields in
this word are as follows (values are in hex):</font><p><font
face="Times">LCRTBS 0x0001 Backspace on erase rather than
echoing erase</font></p>
<p><font face="Times">LPRTERA 0x0002 Printing terminal
erase mode</font></p>
<p><font face="Times">LCRTERA 0x0004 Erase character
echoes as backspace-space-backspace</font></p>
<p><font face="Times">LTILDE 0x0008 Convert ~ to ` on
output (for Hazeltine terminals)</font></p>
<p><font face="Times">LMDMBUF 0x0010 Stop/start output
when carrier drops</font></p>
<p><font face="Times">LLITOUT 0x0020 Suppress output
translations</font></p>
<p><font face="Times">LTOSTOP 0x0040 Send SIGTTOU for
background output (not implemented)</font></p>
<p><font face="Times">LFLUSHO 0x0080 Output is being
flushed</font></p>
<p><font face="Times">LNOHANG 0x0100 Don't send hangup
when carrier drops</font></p>
<p><font face="Times">LPASSOUT 0x0200 Cooked mode with
8-bit output</font></p>
<p><font face="Times">LCRTKIL 0x0400 BS-space-BS erase
entire line on line kill</font></p>
<p><font face="Times">LPASS8 0x0800 Pass all 8 bits
through on input, in any mode</font></p>
<p><font face="Times">LCTLECH 0x1000 Echo input control
chars as ^?</font></p>
<p><font face="Times">LPENDIN 0x2000 Retype pending input
at next read or input character</font></p>
<p><font face="Times">LDECCTQ 0x4000 Only ^Q restarts
output after ^S</font></p>
<p><font face="Times">LNOFLSH 0x8000 Inhibit flushing of
pending I/O when intr char is typed</font></p>
<p><font face="Times">The ioctl's used to access the
local mode follow. arg in all cases is a pointer to an
int.</font></p>
<p><font face="Courier"><b>TIOCLBIS</b></font><font
face="Times"> The bits of the local mode word specified
by `1' bits in the argument are set; this operation is a
bit-wise OR.</font></p>
<p><font face="Courier"><b>TIOCLBIC</b></font><font
face="Times"> The bits of the local mode word specified
by `1' bits in the argument are cleared; this operation
ANDs the local mode with the bitwise negation of the
argument.</font></p>
<p><font face="Courier"><b>TIOCLSET</b></font><font
face="Times"> Sets the local mode word to the value of
the argument.</font></p>
<p><font face="Courier"><b>TIOCLGET</b></font><font
face="Times"> Returns the local mode word in the int
pointed to by arg.</font></p>
</li>
</dir>
<p><font face="Times"><b>Local Special Characters</b></font></p>
<dir>
<li><font face="Times">The fourth terminal structure is
another set of special characters. The structure is named
ltchars and is again defined in &lt;ioctl.h&gt;.</font><p><font
size="2" face="Courier">struct ltchars {</font></p>
<p><font size="2" face="Courier">char t_suspc; /* stop
process signal */</font></p>
<p><font size="2" face="Courier">char t_dsuspc; /*
delayed stop process signal */</font></p>
<p><font size="2" face="Courier">char t_rprntc; /*
reprint line */</font></p>
<p><font size="2" face="Courier">char t_flushc; /* flush
output (toggles) */</font></p>
<p><font size="2" face="Courier">char t_werasc; /* word
erase */</font></p>
<p><font size="2" face="Courier">char t_lnextc; /*
literal next character */</font></p>
<p><font size="2" face="Courier">};</font></p>
<p><font face="Times">Defaults for these characters are
^Z, ^Y, ^R, ^O, ^W, and ^V. As with tchars, a value of -1
disables the effect of that character. Only t_suspc is
currently implemented for the console driver.</font></p>
<p><font face="Times">The applicable ioctl functions are:</font></p>
<p><font face="Courier"><b>TIOCSLTC</b></font><font
face="Times"> sets the local characters according to the
ltchars structure pointed to by arg.</font></p>
<p><font face="Courier"><b>TIOCGLTC</b></font><font
face="Times"> retreives the local characters, storing
them in the argument.</font></p>
</li>
</dir>
<p><font face="Times"><b>Window/terminal sizes</b></font></p>
<p>&nbsp;</p>
<dir>
<li><font face="Times">Provision is made for storage of the
current window or terminal size along with the other
terminal information. This info is recorded in a winsize
structure, and is defined in &lt;ioctl.h&gt;:</font><p><font
size="2" face="Courier">struct winsize {</font></p>
<p><font size="2" face="Courier">unsigned short ws_row;
/* rows, in characters */</font></p>
<p><font size="2" face="Courier">unsigned short ws_col;
/* columns, in characters */</font></p>
<p><font size="2" face="Courier">unsigned short
ws_xpixel; /* horizontal size, pixels */</font></p>
<p><font size="2" face="Courier">unsigned short
ws_ypixel; /* vertical size, pixels */</font></p>
<p><font size="2" face="Courier">};</font></p>
<p><font face="Times">A '0' in a field indicates that the
field value is undefined. '0' is the default when a
terminal is first opened. These values are not used by
the terminal driver itself; rather, they are for the
benefit of applications. The ioctl calls for winsize are:</font></p>
<p><font face="Courier"><b>TIOCGWINSZ</b></font><font
face="Times"> Returns the window size parameters in the
provided winsize structure.</font></p>
<p><font face="Courier"><b>TIOCSWINSZ</b></font><font
face="Times"> Sets the window size parameters. If any of
the values differ from the old ones, a SIGWINCH signal is
sent to the terminal's process group.</font></p>
</li>
</dir>
<p><font face="Times"><b>FILES</b></font></p>
<dir>
<li><font face="Times">.tty</font><p><font face="Times">.ttyco
(console driver)</font></p>
<p><font face="Times">.tty* (user-installed drivers)</font></p>
</li>
</dir>
<p><font face="Times"><b>SEE ALSO</b></font></p>
<dir>
<li><font face="Times"><i>GNO Shell Reference Manual</i>, <b>stty</b>(1),
<b>ioctl</b>(2), <b>signal</b>(2)</font></li>
</dir>
</body>
</html>