#include <grp.h> #include <sys/types.h>
int initgroups(const char *name, gid_t basegid);
The initgroups() function reads the group database to get the group membership for the user specified by name, and initializes the supplementary group access list of the calling process (see getgrnam(3C) and getgroups(2)). The basegid group ID is also included in the supplementary group access list. This is typically the real group ID from the user database.
While scanning the group database, if the number of groups, including the basegid entry, exceeds NGROUPS_MAX, subsequent group entries are ignored.
Upon successful completion, 0 is returned. Otherwise, -1 is returned and errno is set to indicate the error.
The initgroups() function will fail and not change the supplementary group access list if:
EPERM The {PRIV_PROC_SETID} privilege is not asserted in the effective set of the calling process.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
| MT-Level | MT-Safe |
getgroups(2), getgrnam(3C), attributes(5)