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.\" and Copyright (c) 2020 by Michael Kerrisk <mtk.manpages@gmail.com>
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.TH id_t 3type 2023-10-31 "Linux man-pages 6.7"
.SH NAME
pid_t, uid_t, gid_t, id_t \- process/user/group identifier
.SH LIBRARY
Standard C library
.RI ( libc )
.SH SYNOPSIS
.nf
.B #include <sys/types.h>
.P
.BR typedef " /* ... */ " pid_t;
.BR typedef " /* ... */ " uid_t;
.BR typedef " /* ... */ " gid_t;
.BR typedef " /* ... */ " id_t;
.fi
.SH DESCRIPTION
.I pid_t
is a type used for storing process IDs, process group IDs, and session IDs.
It is a signed integer type.
.P
.I uid_t
is a type used to hold user IDs.
It is an integer type.
.P
.I gid_t
is a type used to hold group IDs.
It is an integer type.
.P
.I id_t
is a type used to hold a general identifier.
It is an integer type that can be used to contain a
.IR pid_t ,
.IR uid_t ,
or
.IR gid_t .
.SH STANDARDS
POSIX.1-2008.
.SH HISTORY
POSIX.1-2001.
.SH NOTES
The following headers also provide
.IR pid_t :
.IR <fcntl.h> ,
.IR <sched.h> ,
.IR <signal.h> ,
.IR <spawn.h> ,
.IR <sys/msg.h> ,
.IR <sys/sem.h> ,
.IR <sys/shm.h> ,
.IR <sys/wait.h> ,
.IR <termios.h> ,
.IR <time.h> ,
.IR <unistd.h> ,
and
.IR <utmpx.h> .
.P
The following headers also provide
.IR uid_t :
.IR <pwd.h> ,
.IR <signal.h> ,
.IR <stropts.h> ,
.IR <sys/ipc.h> ,
.IR <sys/stat.h> ,
and
.IR <unistd.h> .
.P
The following headers also provide
.IR gid_t :
.IR <grp.h> ,
.IR <pwd.h> ,
.IR <signal.h> ,
.IR <stropts.h> ,
.IR <sys/ipc.h> ,
.IR <sys/stat.h> ,
and
.IR <unistd.h> .
.P
The following header also provides
.IR id_t :
.IR <sys/resource.h> .
.SH SEE ALSO
.BR chown (2),
.BR fork (2),
.BR getegid (2),
.BR geteuid (2),
.BR getgid (2),
.BR getgroups (2),
.BR getpgid (2),
.BR getpid (2),
.BR getppid (2),
.BR getpriority (2),
.BR getpwnam (3),
.BR getresgid (2),
.BR getresuid (2),
.BR getsid (2),
.BR gettid (2),
.BR getuid (2),
.BR kill (2),
.BR pidfd_open (2),
.BR sched_setscheduler (2),
.BR waitid (2),
.BR getgrnam (3),
.BR sigqueue (3),
.BR credentials (7)