|CONFSTR(3)||Linux Programmer's Manual||CONFSTR(3)|
NAME¶confstr - get configuration dependent string variables
#include <unistd.h> size_t confstr(int name, char *buf, size_t len);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
confstr(): _POSIX_C_SOURCE >= 2 || _XOPEN_SOURCE
DESCRIPTION¶confstr() gets the value of configuration-dependent string variables. The name argument is the system variable to be queried. The following variables are supported:
- _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 PATH variable which indicates where all the POSIX.2 standard utilities can be found.
RETURN VALUE¶If name is a valid configuration variable, 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 greater than len, which means that the value in buf is truncated. If name is a valid configuration variable, but that variable does not have a value, then confstr() returns 0. If name does not correspond to a valid configuration variable, confstr() returns 0, and errno is set to EINVAL.
- The value of name is invalid.
EXAMPLE¶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);
SEE ALSO¶getconf(1), sh(1), exec(3), fpathconf(3) sysconf(3) pathconf(3) system(3)
COLOPHON¶This page is part of release 3.74 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at http://www.kernel.org/doc/man-pages/.