gettid(2) — Linux manual page

gettid(2)                  System Calls Manual                 gettid(2)

NAME 

       gettid - get thread identification

LIBRARY 

       Standard C library (libc, -lc)

SYNOPSIS 

       #define _GNU_SOURCE
       #include <unistd.h>

       pid_t gettid(void);

DESCRIPTION 

       gettid() returns the caller's thread ID (TID).  In a single-
       threaded process, the thread ID is equal to the process ID (PID,
       as returned by getpid(2)).  In a multithreaded process, all
       threads have the same PID, but each one has a unique TID.  For
       further details, see the discussion of CLONE_THREAD in clone(2).

RETURN VALUE 

       On success, returns the thread ID of the calling thread.

ERRORS 

       This call is always successful.

STANDARDS 

       Linux.

HISTORY 

       Linux 2.4.11, glibc 2.30.

NOTES 

       The thread ID returned by this call is not the same thing as a
       POSIX thread ID (i.e., the opaque value returned by
       pthread_self(3)).

       In a new thread group created by a clone(2) call that does not
       specify the CLONE_THREAD flag (or, equivalently, a new process
       created by fork(2)), the new process is a thread group leader,
       and its thread group ID (the value returned by getpid(2)) is the
       same as its thread ID (the value returned by gettid()).

SEE ALSO 

       capget(2), clone(2), fcntl(2), fork(2), get_robust_list(2),
       getpid(2), ioprio_set(2), perf_event_open(2),
       sched_setaffinity(2), sched_setparam(2), sched_setscheduler(2),
       tgkill(2), timer_create(2)

COLOPHON 

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       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
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Linux man-pages 6.9.1          2024-05-02                      gettid(2)

Pages that refer to this page: kill(1), strace(1), capget(2), clone(2), fcntl(2), futex(2), getpid(2), get_robust_list(2), ioprio_set(2), PR_SET_NAME(2const), ptrace(2), sched_setaffinity(2), sched_setparam(2), sched_setscheduler(2), seccomp(2), set_tid_address(2), syscalls(2), timer_create(2), tkill(2), id_t(3type), pthread_self(3), sd_event_new(3), proc_pid_status(5), proc_pid_task(5), cgroups(7), cpuset(7), pthreads(7)

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