December 15, 2015
getgid, getegid - get group process identification
.In unistd.h gid_t
getgidsystem call returns the real group ID of the calling process,
getegidreturns the effective group ID of the calling process.
The real group ID is specified at login time.
The real group ID is the group of the user who invoked the program. As the effective group ID gives the process additional permissions during the execution of "set-group-ID" mode processes,
getgidis used to determine the real-user-id of the calling process.
getegidsystem calls are always successful, and no return value is reserved to indicate an error.
getegidsystem calls are expected to conform to -p1003.1-90.