SETRESUID Section: Linux Programmer's Manual (2) Updated: 16 July 2025 Index   NAME setresuid, setresgid - set real, effective and saved user or group ID   SYNOPSIS #include <unistd.h> int setresuid(uid_t ruid, uid_t euid, uid_t suid); int setresgid(gid_t rgid, gid_t egid, gid_t sgid);   DESCRIPTION setresuid (introduced in Linux 2.1.44) sets the real, effective and saved user ID's of the current process. Unprivileged user processes (i.e., processes with each of real, effective and saved user ID nonzero) may change the real, effective and saved user ID, each to one of: the current uid, the current effective uid or the current saved uid. The super-user may set real, effective and saved user ID to arbitrary values. If one of the parameters equals -1, the corresponding value is not changed. Completely analogously, setresgid sets the real, effective and saved group ID's of the current process, with the same restrictions for processes with each of real, effective and saved user ID nonzero.   RETURN VALUE On success, zero is returned. On error, -1 is returned, and errno is set appropriately.   ERRORS EPERM The current process was not privileged and tried to change the IDs is a not allowed way.   CONFORMING TO This call is Linux-specific.   SEE ALSO   Index NAME SYNOPSIS DESCRIPTION RETURN VALUE ERRORS CONFORMING TO SEE ALSO This document was created by using the manual pages. Time: 11:56:07 GMT, March 24, 2025