x                  Pointer to a valid group structure containing
                       a matching entry.
    NULL               Indicates an error.

                       Note: The return value points to a static area
                       which is overwritten by subsequent calls to
                       getgrent, getgrgid, or getgrnam.

                       On error, the function sets the return value
                       to one of the following:

                       o  EACCES - The user process does not have
                          appropriate privileges enabled to access
                          the user authorization file.

                       o  EIO - An I/O error has occurred.

                       o  EINTR - A signal was intercepted during
                          getgrnam.

                       o  EMFILE - OPEN_MAX file descriptors are
                          currently open in the calling process.

                       o  ENFILE - The maximum allowable number of
                          files is currently open in the system.

                       Applications wishing to check for error
                       situations should set errno to 0 before
                       calling getgrnam. If errno is set on return,
                       an error occurred.