#include <unistd.h> #include <stdio.h> #include <errno.h> int seteuid(uid_t uid) { switch (sizeof (uid_t)) { case 2: if (uid == 65535) { errno = EINVAL; return -1; } break; default: fprintf (stderr, "Uknown uid_t size and sign\n"); } return setreuid(-1, uid); }