getegid

   With POSIX IDs disabled, this function is equivalent to getgid
   and returns the group number from the user identification code
   (UIC).

   With POSIX IDs enabled, this function returns the effective group
   ID of the calling process.

   Format

     #include  <unistd.h>

     gid_t getegid  (void);
 

Additional information available:

Description     Return_Value