NAME

       pid_t, uid_t, gid_t, id_t - process/user/group identifier

LIBRARY

       Standard C library (libc)

SYNOPSIS

       #include <sys/types.h>

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

DESCRIPTION

       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.

STANDARDS

       POSIX.1-2008.

HISTORY

       POSIX.1-2001.

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>.

SEE ALSO

       chown(2), fork(2), getegid(2), geteuid(2), getgid(2), getgroups(2), getpgid(2), getpid(2),
       getppid(2), getpriority(2), getpwnam(3), getresgid(2), getresuid(2), getsid(2), gettid(2),
       getuid(2),   kill(2),   pidfd_open(2),   sched_setscheduler(2),   waitid(2),  getgrnam(3),
       sigqueue(3), credentials(7)