confstr - get configuration dependent string variables
#define _POSIX_C_SOURCE 2 or #define _XOPEN_SOURCE #include <unistd.h>
size_t confstr(int name, char *buf, size_t len);
confstr() gets the value of configuration-dependent string variables.
The name argument is the system variable to be queried. The following variables are supported:
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 character as termination. This can be detected by comparing the return value of confstr() against len.
_CS_PATH A value for the PATH variable which indicates where all the POSIX.2 standard utilities can be found.
If len is zero and buf is NULL, confstr() just returns the value as defined below.
If name does not correspond to a valid configuration variable, confstr() returns 0.
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); if ((pathbuf = malloc(n)) == NULL) abort(); confstr(_CS_PATH, pathbuf, n);
If the value of name is invalid, errno is set to EINVAL.
POSIX.2 is not yet an approved standard; the information in this manpage is subject to change.
sh(1), exec(3), system(3)