1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)setregid.2 8.1 (Berkeley) 06/02/93 7.\" 8.Dd 9.Dt SETREGID 2 10.Os BSD 4.2 11.Sh NAME 12.Nm setregid 13.Nd set real and effective group ID 14.Sh SYNOPSIS 15.Fd #include <unistd.h> 16.Ft int 17.Fn setregid "int rgid" "int egid" 18.Sh DESCRIPTION 19The real and effective group ID's of the current process 20are set to the arguments. 21Unprivileged users may change the real group 22ID to the effective group ID and vice-versa; only the super-user may 23make other changes. 24.Pp 25Supplying a value of -1 for either the real or effective 26group ID forces the system to substitute the current 27ID in place of the -1 parameter. 28.Pp 29The 30.Fn setregid function was intended to allow swapping 31the real and effective group IDs 32in set-group-ID programs to temporarily relinquish the set-group-ID value. 33This function did not work correctly, 34and its purpose is now better served by the use of the 35.Fn setegid 36function (see 37.Xr setuid 2 ) . 38.Pp 39When setting the real and effective group IDs to the same value, 40the standard 41.Fn setgid 42function is preferred. 43.Sh RETURN VALUES 44Upon successful completion, a value of 0 is returned. Otherwise, 45a value of -1 is returned and 46.Va errno 47is set to indicate the error. 48.Sh ERRORS 49.Bl -tag -width [EPERM] 50.It Bq Er EPERM 51The current process is not the super-user and a change 52other than changing the effective group-id to the real group-id 53was specified. 54.El 55.Sh SEE ALSO 56.Xr getgid 2 , 57.Xr setegid 2 , 58.Xr setgid 2 , 59.Xr setuid 2 60.Sh HISTORY 61The 62.Nm 63function call appeared in 64.Bx 4.2 65and was dropped in 66.Bx 4.4 . 67