getgid(2)
Name
getgid, getegid − get group identity
Syntax
#include <sys/types.h>
#include <unistd.h>
gid = getgid()
gid_t gid;
egid = getegid()
gid_t egid;
Description
The getgid system call returns the real group ID of the current process, and the getegid call returns the effective group ID.
The real group ID is specified at login time.
The effective group ID is more transient and determines additional access permission during execution of a “set-group-ID” process. The getgid call is most useful with processes that are “set-group-ID.”
Environment
Differs from the System V definition in that the return values are of type int, instead of type unsigned short.