getuid(2)

getuid2

Get user identification

Usage

#include <unistd.h>

uid_t

geteuid(void);

uid_t

getuid(void);

Overview

The getuid() function returns the real user ID of the calling process. The geteuid() function returns the effective user ID of the calling process.

The real user ID is that of the user who has invoked the program. As the effective user ID gives the process additional permissions during execution of “set-user-ID” mode processes, getuid() is used to determine the real-user-id of the calling process.

Errors

The getuid() and geteuid() functions are always successful, and no return value is reserved to indicate an error.

Legacy synopsis

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

The include file ⟨sys/types.h⟩ is necessary for both functions.

Releases

155 releases since Mac OS X 10.0; the text changed 2 times.

  1. 10.0–10.4.11
  2. 10.5–10.11.6
  3. 10.12–26.5

Standards

geteuid() and getuid() functions conform to IEEE Std 1003.1-1988 (“POSIX.1”).

From xnu 12377.121.6 in macOS 26.5. Parsed by carta from the page's mdoc source.