.TH SETUID 2
.CT 2 sa secur
.SH NAME
setuid, setgid, setruid, setlogname \(mi set userid and groupid
.SH SYNOPSIS
.nf
.B int setuid(uid)
.PP
.B int setgid(gid)
.PP
.B int setruid(uid)
.PP
.B int setlogname(buf)
.B char buf[8];
.fi
.SH DESCRIPTION
.I Setuid
.RI ( setgid )
sets the effective and real userid (groupid) of the current process to
.I uid
.RI ( gid ).
Both the effective and the real userid (groupid) are set.
.I Setruid
only sets the real userid.
These calls are only permitted to the super-user
or if the argument is the real or effective userid.
.I Setruid
may only be used by the super-user.
.PP
.I Setlogname
sets the login name
returned by
.IR getlogname .
Only the super-user may use this call.
For all of these calls, capability
.B T_UAREA
is required whenever superuser status is required; see
.IR getplab (2).
.PP
Certain ids have predefined uses:
.IP
uid 0	superuser
.br
gid \-1	automatically assigned to /proc files
.SH "SEE ALSO"
.IR getuid (2)
.SH DIAGNOSTICS
.B EFAULT
.RI ( "setlogname " only),
.B EPERM