1GETTID(2) Linux Programmer's Manual GETTID(2)
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6 gettid - get thread identification
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9 #include <sys/types.h>
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11 pid_t gettid(void);
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13 Note: There is no glibc wrapper for this system call; see NOTES.
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16 gettid() returns the caller's thread ID (TID). In a single-threaded
17 process, the thread ID is equal to the process ID (PID, as returned by
18 getpid(2)). In a multithreaded process, all threads have the same PID,
19 but each one has a unique TID. For further details, see the discussion
20 of CLONE_THREAD in clone(2).
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23 On success, returns the thread ID of the calling process.
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26 This call is always successful.
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29 The gettid() system call first appeared on Linux in kernel 2.4.11.
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32 gettid() is Linux-specific and should not be used in programs that are
33 intended to be portable.
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36 Glibc does not provide a wrapper for this system call; call it using
37 syscall(2).
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39 The thread ID returned by this call is not the same thing as a POSIX
40 thread ID (i.e., the opaque value returned by pthread_self(3)).
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42 In a new thread group created by a clone(2) call that does not specify
43 the CLONE_THREAD flag (or, equivalently, a new process created by
44 fork(2)), the new process is a thread group leader, and its thread
45 group ID (the value returned by getpid(2)) is the same as its thread ID
46 (the value returned by gettid()).
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49 capget(2), clone(2), fcntl(2), fork(2), getpid(2), get_robust_list(2),
50 ioprio_set(2), perf_event_open(2), sched_setaffinity(2), sched_set‐
51 param(2), sched_setscheduler(2), tgkill(2), timer_create(2)
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54 This page is part of release 4.16 of the Linux man-pages project. A
55 description of the project, information about reporting bugs, and the
56 latest version of this page, can be found at
57 https://www.kernel.org/doc/man-pages/.
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61Linux 2017-09-15 GETTID(2)