SETREGID(2) System Calls Manual SETREGID(2)

setregid — set real and effective group ID

Standard C Library (libc, -lc)

#include <unistd.h>

int
setregid(gid_t rgid, gid_t egid);

The real and effective group ID's of the current process are set to the arguments. Unprivileged users may change the real group ID to the effective group ID and vice-versa; only the super-user may make other changes.

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 parameter.

The () function was intended to allow swapping the real and effective group IDs in set-group-ID programs to temporarily relinquish the set-group-ID value. This function did not work correctly; its purpose is now better served by the use of the () function (see setuid(2)).

When setting the real and effective group IDs to the same value, the standard () function is preferred.

The setregid() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

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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.

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

The setregid() system call appeared in 4.2BSD.

April 16, 1994 macOS 15.2