confstr — get configuration dependent string variables
confstr() gets the value of
configuration-dependent string variables.
is the system variable to be queried. The following variables
_CS_GNU_LIBC_VERSION(GNU C library only; since glibc 2.3.2)
A string which identifies the GNU C library version on this system (e.g., "glibc 2.3.4").
_CS_GNU_LIBPTHREAD_VERSION(GNU C library only; since glibc 2.3.2)
A string which identifies the POSIX implementation supplied by this C library (e.g., "NPTL 2.3.4" or "linuxthreads-0.10").
A value for the
variable which indicates where all the POSIX.2 standard
utilities can be found.
buf is not NULL
len is not zero,
confstr() copies the value of
the string to
truncated to len −
1 bytes if necessary, with a null byte ('\0') as
terminator. This can be detected by comparing the return
len is zero and
buf is NULL,
confstr() just returns the
value as defined below.
name is a valid
confstr() returns the number of bytes
(including the terminating null byte) that would be required
to hold the entire value of that variable. This value may be
which means that the value in
buf is truncated.
name is a valid
configuration variable, but that variable does not have a
name does not
correspond to a valid configuration variable,
confstr() returns 0, and
errno is set to EINVAL.
For an explanation of the terms used in this section, see attributes(7).
The following code fragment determines the path where to find the POSIX.2 system utilities:
char *pathbuf; size_t n; n = confstr(_CS_PATH, NULL, (size_t) 0); pathbuf = malloc(n); if (pathbuf == NULL) abort(); confstr(_CS_PATH, pathbuf, n);
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and the latest version of this page, can be found at
Copyright (c) 1993 by Thomas Koenig (ig25rz.uni-karlsruhe.de)
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Since the Linux kernel and libraries are constantly changing, this
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which is licensed free of charge, as they might when working
Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.
Modified Sat Jul 24 19:53:02 1993 by Rik Faith (faithcs.unc.edu)
FIXME Many more values for 'name' are supported, some of which
are documented under 'info confstr'.
See <bits/confname.h> for the rest.
These should all be added to this page.
See also the POSIX.1-2001 specification of confstr()