Name
initgroups -- initialize the supplementary group access list
Synopsis
| #include <grp.h>
#include <sys/types.h>
int initgroups(const char *user, gid_t group); | 
Description
The initgroups() function initializes the group access list by reading the group database /etc/group and using all groups of which user is a member. The additional group group is also added to the list.
Return Value
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
Errors
- EPERM
- The calling process does not have sufficient privileges. 
- ENOMEM
- Insufficient memory to allocate group information structure. 
Files
/etc/group group database file