getuid(2)

NAME
     getuid, geteuid - get user identity

SYNOPSIS
     #include <sys/types.h>
     #include <unistd.h>

     uid_t getuid(void)
     uid_t geteuid(void)

DESCRIPTION
     Getuid returns the real user ID  of  the  current  process,  geteuid  the
     effective user ID.

     The real user ID identifies the person who is logged in.   The  effective
     user  ID  gives  the  process  additional permissions during execution of
     "set-user-ID" mode processes, which use getuid  to  determine  the  real-
     user-id of the process that invoked them.

SEE ALSO
     getgid(2), setuid(2).