January 5, 2001 SETREGID 2

### NAME

setregid - set real and effective group ID's

### LIBRARY

Standard C Library (libc, -lc)

### SYNOPSIS

```int` setregid(```gid_t rgid``, gid_t egid`)

### DESCRIPTION

This interface is made obsolete by the saved ID functionality in setgid(2) and setegid(2).

The real and effective group ID's of the current process are set according 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.

If ```rgid` or ```egid` is -1, the current gid is filled in by the system. Unprivileged users may change the real group ID to the effective group ID, and may change the effective group ID to the real group ID or the saved group ID; only the super-user may make other changes.

The setregid(``) function has been used to swap the real and effective group IDs in set-group-ID programs to temporarily relinquish the set-group-ID value. This purpose is now better served by the use of the setegid(``) function (see setgid(2)).

When setting the real and effective group IDs to the same value, this function is equivalent to the setgid(``) function. When setting only the effective group ID, this function is equivalent to the setegid(``) function.

### RETURN VALUES

Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error.

### ERRORS

[```EPERM`]
  The current process is not the super-user and a change other than changing the effective group-id to the real group-id was specified.

### SEE ALSO

getgid(2), setegid(2), setgid(2), setuid(2)

### HISTORY

The setregid(``) function call appeared in 4.2BSD. An incompatible version was implemented in 4.4BSD. It was reimplemented in NetBSD1.2 in a way compatible with 4.3BSD, SunOS and Linux, but should not be used in new code.