setreuid(2)
NAME
setreuid − set real and effective user IDs
SYNTAX
int setreuid(ruid, euid)
int ruid, euid;
DESCRIPTION
The setreuid system call sets the real and effective user IDs of the current process to ruid and euid. If either ruid or euid is a −1, the appropriate uid is filled in by the system.
RESTRICTIONS
Only the superuser may modify the real uid of a process. Users other than the superuser may change the effective uid of a process only to the real uid.
RETURN VALUE
If unsuccessful, returns a −1, and the global variable errno indicates the error code.
DIAGNOSTICS
The setreuid call will fail if:
[EPERM] The current process is not the superuser, and a change other than changing the effective user ID to the real user ID was specified.