setregid - set real and effective group IDs
setregid(gid_t rgid, gid_t egid);
The real and effective group IDs of the current process are
to the arguments. If the real group ID is changed, the
saved group ID is
changed to the new value of the effective group ID.
Unprivileged users may change either group ID to the current
value of the
real, effective, or saved group ID. Only the superuser may
Supplying a value of -1 for either the real or effective
group ID forces
the system to substitute the current ID in place of the -1
The setregid() function was intended to allow swapping the
real and effective
group IDs in set-group-ID programs to temporarily
set-group-ID value. This purpose is now better served by
the use of the
setegid() function (see setuid(2)).
When setting the real and effective group IDs to the same
setgid() function is preferred.
Upon successful completion, a value of 0 is returned. Otherwise, a value
of -1 is returned and errno is set to indicate the error.
[EPERM] The current process is not the superuser and a
than changing the effective group ID to the
real group ID
getgid(2), setegid(2), setgid(2), setresgid(2), setuid(2)
The setregid() function conforms to the IEEE Std 1003.1-2001
and X/Open Portability Guide Issue 4.3 (``XPG4.3''). specifications.
Note, however, that prior to IEEE Std 1003.1-2001
setregid() function was not a part of the IEEE Std 1003.1
specification. As a result, it may not be implemented on
The setregid() function call appeared in 4.2BSD. A semantically different
version appeared in 4.4BSD. The current version, with
semantics restored, appeared in OpenBSD 3.3.
The setregid() function predates POSIX saved group IDs.
changes the saved group ID to the new value of the effective group
ID if the real group ID is changed. Other implementations
OpenBSD 3.6 January 29, 2003
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