gid

    The group ID of the group for which the group database entry is
    to be retrieved.

 grp

    Storage area to hold the retrieved group structure.

 buffer

    The working buffer that is able to hold the longest group entry
    in the database.

 bufsize

    The length, in characters, of buffer.

 result

    Upon successful return, result points to the retrieved group
    structure.

    Upon unsuccessful return, result is set to NULL.