CONFSTR

NAME

SYNOPSIS

#include <unistd.h>

size_t confstr(int name, char *buf, size_t len);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

getcwd(): _POSIX_C_SOURCE >= 2 || _XOPEN_SOURCE || _POSIX_SOURCE  

DESCRIPTION

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").

_CS_PATH

A value for the PATH variable which indicates where all the POSIX.2 standard utilities can be found.

If buf is not NULL and len is not zero, confstr() copies the value of the string to buf truncated to len - 1 characters if necessary, with a null byte (aq\0aq) as terminator. This can be detected by comparing the return value of confstr() against len.

If len is zero and buf is NULL, confstr() just returns the value as defined below.  

RETURN VALUE

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.  

ERRORS

EINVAL

If the value of name is invalid.

CONFORMING TO

EXAMPLE

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

COLOPHON