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CONFSTR(3)		   Linux Programmer's Manual		    CONFSTR(3)

NAME
       confstr - get configuration dependent string variables

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)):

       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 sys-
	      tem (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 bytes if necessary, with a  null
       byte  ('\0')  as	terminator.  This can be detected by comparing the re-
       turn value of confstr() against len.

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

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.

ERRORS
       EINVAL The value	of name	is invalid.

CONFORMING TO
       POSIX.1-2001.

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)  sys-
       tem(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/.

GNU				  2014-03-20			    CONFSTR(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | EXAMPLE | SEE ALSO | COLOPHON

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