initgroups() — Initialize the supplementary group ID list for the process

Standards

Standards / Extensions C or C++ Dependencies
z/OS® UNIX both  

Format

#define _OPEN_SYS
#include <sys/types.h>
#include <grp.h>

int initgroups(const char *user, const gid_t basegid);

General description

The initgroups() function obtains the supplementary group membership of user, and sets the current process supplementary group IDs to that list. The basegid is also included in the supplementary group IDs list.

The caller of this function must be a superuser or must specify the password of the target user name specified on the initgroups() call - issue the passwd() function before initgroups().

Returned value

If successful, initgroups() returns 0.

If unsuccessful, initgroups() returns -1 and sets errno to one of the following values:
Error Code
Description
EINVAL
The number of supplementary groups for the specified user plus the basegid group exceeds the maximum number of groups allowed, or a non-valid user is specified.
EMVSERR
An MVS™ environmental or internal error occurred.
EMVSSAF2ERR
The Security Authorization Facility (SAF) had an error.
EPERM
The caller is not authorized, only authorized users are allowed to alter the supplementary group IDs list.

Related information

Parent topic: Library functions