1GETTID(2)                  Linux Programmer's Manual                 GETTID(2)
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NAME

6       gettid - get thread identification
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SYNOPSIS

9       #include <sys/types.h>
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11       pid_t gettid(void);
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DESCRIPTION

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

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

24       This call is always successful.
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VERSIONS

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

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

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

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

52       This page is part of release 5.04 of the Linux  man-pages  project.   A
53       description  of  the project, information about reporting bugs, and the
54       latest    version    of    this    page,    can     be     found     at
55       https://www.kernel.org/doc/man-pages/.
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59Linux                             2019-03-06                         GETTID(2)
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