SETUID(3)
NAME
setuid, seteuid, setruid, setgid, setegid, setrgid − set user and group ID
USAGE
setuid(uid)
seteuid(euid)
setruid(ruid)
setgid(gid)
setegid(egid)
setrgid(rgid)
DESCRIPTION
Setuid (setgid) sets both the real and effective user ID (group ID) of the current process to the ID specified in the function.
Seteuid (setegid) sets the effective user ID (group ID) of the current process.
Setruid (setruid) sets the real user ID (group ID) of the current process.
Only the super-user may use these calls, unless the argument is the real or effective ID.
DIAGNOSTICS
Zero is returned if the user (group) ID is set; −1 is returned otherwise.