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man pages section 2: System Calls

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Updated: Thursday, June 13, 2019
 
 

getuid(2)

Name

getuid, geteuid, getgid, getegid - get real user, effective user, real group, and effective group IDs

Synopsis

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

uid_t getuid(void);
uid_t geteuid(void);
gid_t getgid(void);
gid_t getegid(void);

Description

The getuid() function returns the real user ID of the calling process. The real user ID identifies the person who is logged in.

The geteuid() function returns the effective user ID of the calling process. The effective user ID gives the process various permissions during execution of “set-user-ID” mode processes which use getuid() to determine the real user ID of the process that invoked them.

The getgid() function returns the real group ID of the calling process.

The getegid() function returns the effective group ID of the calling process.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
MT-Level
Async-Signal-Safe
Standard

See Also

Intro(2), setuid(2), attributes(7), standards(7)