pid_t(3type)

pid_t3type

Process/user/group identifier

Part of id_t(3type).

Usage

#include <sys/types.h>

typedef /* ... */ pid_t; typedef /* ... */ uid_t; typedef /* ... */ gid_t; typedef /* ... */ id_t;

Library

Standard C library (libc)

Overview

pid_t is a type used for storing process IDs, process group IDs, and session IDs. It is a signed integer type.

uid_t is a type used to hold user IDs. It is an integer type.

gid_t is a type used to hold group IDs. It is an integer type.

id_t is a type used to hold a general identifier. It is an integer type that can be used to contain a pid_t, uid_t, or gid_t.

Notes

The following headers also provide pid_t: <fcntl.h>, <sched.h>, <signal.h>, <spawn.h>, <sys/msg.h>, <sys/sem.h>, <sys/shm.h>, <sys/wait.h>, <termios.h>, <time.h>, <unistd.h>, and <utmpx.h>.

The following headers also provide uid_t: <pwd.h>, <signal.h>, <stropts.h>, <sys/ipc.h>, <sys/stat.h>, and <unistd.h>.

The following headers also provide gid_t: <grp.h>, <pwd.h>, <signal.h>, <stropts.h>, <sys/ipc.h>, <sys/stat.h>, and <unistd.h>.

The following header also provides id_t: <sys/resource.h>.

Releases

3 releases since Debian 12 (Bookworm); the text changed 2 times.

  1. 12
  2. 13
  3. Arch

Standards

POSIX.1-2024.

History

pid_tuid_tgid_t

POSIX.1-1988.

id_t

SUSv1, POSIX.1-2001 XSI, POSIX.1-2008.

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.