SETGID(2) Linux Programmer's Manual SETGID(2)

setgid - set group identity

#include <sys/types.h>
#include <unistd.h>

int setgid(gid_t gid);

setgid() sets the effective group ID of the calling process. If the caller is the superuser, the real GID and saved set-group-ID are also set.

Under Linux, setgid() is implemented like the POSIX version with the _POSIX_SAVED_IDS feature. This allows a set-group-ID program that is not set-user-ID-root to drop all of its group privileges, do some un-privileged work, and then re-engage the original effective group ID in a secure manner.

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

The calling process is not privileged (does not have the CAP_SETGID capability), and gid does not match the effective group ID or saved set-group-ID of the calling process.

SVr4, POSIX.1-2001.

getgid(2), setegid(2), setregid(2), capabilities(7), credentials(7)

This page is part of release 3.21 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

2002-03-09 Linux

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