1GETTID(2)                  Linux Programmer's Manual                 GETTID(2)
2
3
4

NAME

6       gettid - get thread identification
7

SYNOPSIS

9       #define _GNU_SOURCE
10       #include <unistd.h>
11
12       pid_t gettid(void);
13

DESCRIPTION

15       gettid()  returns  the  caller's thread ID (TID).  In a single-threaded
16       process, the thread ID is equal to the process ID (PID, as returned  by
17       getpid(2)).  In a multithreaded process, all threads have the same PID,
18       but each one has a unique TID.  For further details, see the discussion
19       of CLONE_THREAD in clone(2).
20

RETURN VALUE

22       On success, returns the thread ID of the calling thread.
23

ERRORS

25       This call is always successful.
26

VERSIONS

28       The gettid() system call first appeared on Linux in kernel 2.4.11.  Li‐
29       brary support was added in glibc 2.30.  (Earlier glibc versions did not
30       provide  a  wrapper  for  this  system  call,  necessitating the use of
31       syscall(2).)
32

CONFORMING TO

34       gettid() is Linux-specific and should not be used in programs that  are
35       intended to be portable.
36

NOTES

38       The  thread  ID  returned by this call is not the same thing as a POSIX
39       thread ID (i.e., the opaque value returned by pthread_self(3)).
40
41       In a new thread group created by a clone(2) call that does not  specify
42       the  CLONE_THREAD  flag  (or,  equivalently,  a  new process created by
43       fork(2)), the new process is a thread  group  leader,  and  its  thread
44       group ID (the value returned by getpid(2)) is the same as its thread ID
45       (the value returned by gettid()).
46

SEE ALSO

48       capget(2), clone(2), fcntl(2), fork(2), get_robust_list(2),  getpid(2),
49       ioprio_set(2),   perf_event_open(2),  sched_setaffinity(2),  sched_set‐
50       param(2), sched_setscheduler(2), tgkill(2), timer_create(2)
51

COLOPHON

53       This page is part of release 5.13 of the Linux  man-pages  project.   A
54       description  of  the project, information about reporting bugs, and the
55       latest    version    of    this    page,    can     be     found     at
56       https://www.kernel.org/doc/man-pages/.
57
58
59
60Linux                             2021-03-22                         GETTID(2)
Impressum