projects / thirdparty / man-pages.git / blame
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| fea681da | 1 | .\" Copyright 2003 Abhijit Menon-Sen <ams@wiw.org> |
| fd484056 MK |
2 | .\" and Copyright (C) 2008 Michael Kerrisk <mtk.manpages@gmail.com> |
| 3 | .\" | |
| 5fbde956 | 4 | .\" SPDX-License-Identifier: Linux-man-pages-copyleft |
| fea681da | 5 | .\" |
| 4c1c5274 | 6 | .TH gettid 2 (date) "Linux man-pages (unreleased)" |
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7 | .SH NAME |
| 8 | gettid \- get thread identification | |
| 4ae0b242 AC |
9 | .SH LIBRARY |
| 10 | Standard C library | |
| 8fc3b2cf | 11 | .RI ( libc ", " \-lc ) |
| fea681da | 12 | .SH SYNOPSIS |
| 16718a1c | 13 | .nf |
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14 | .B #define _GNU_SOURCE |
| 15 | .B #include <unistd.h> | |
| 68e4db0a | 16 | .PP |
| fea681da | 17 | .B pid_t gettid(void); |
| c12fd10d | 18 | .fi |
| fea681da | 19 | .SH DESCRIPTION |
| 60a90ecd | 20 | .BR gettid () |
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21 | returns the caller's thread ID (TID). |
| 22 | In a single-threaded process, the thread ID | |
| 23 | is equal to the process ID (PID, as returned by | |
| 24 | .BR getpid (2)). | |
| 25 | In a multithreaded process, all threads | |
| fea681da | 26 | have the same PID, but each one has a unique TID. |
| fd484056 | 27 | For further details, see the discussion of |
| 1ae6b2c7 | 28 | .B CLONE_THREAD |
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29 | in |
| 30 | .BR clone (2). | |
| 47297adb | 31 | .SH RETURN VALUE |
| 56d898aa | 32 | On success, returns the thread ID of the calling thread. |
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33 | .SH ERRORS |
| 34 | This call is always successful. | |
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35 | .SH VERSIONS |
| 36 | The | |
| 37 | .BR gettid () | |
| 38 | system call first appeared on Linux in kernel 2.4.11. | |
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39 | Library support was added in glibc 2.30. |
| 40 | (Earlier glibc versions did not provide a wrapper for this system call, | |
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41 | necessitating the use of |
| 42 | .BR syscall (2).) | |
| 3113c7f3 | 43 | .SH STANDARDS |
| 60a90ecd | 44 | .BR gettid () |
| 8382f16d | 45 | is Linux-specific and should not be used in programs that |
| fea681da | 46 | are intended to be portable. |
| c12fd10d | 47 | .SH NOTES |
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48 | The thread ID returned by this call is not the same thing as a |
| 49 | POSIX thread ID (i.e., the opaque value returned by | |
| 50 | .BR pthread_self (3)). | |
| efeece04 | 51 | .PP |
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52 | In a new thread group created by a |
| 53 | .BR clone (2) | |
| 54 | call that does not specify the | |
| 1ae6b2c7 | 55 | .B CLONE_THREAD |
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56 | flag (or, equivalently, a new process created by |
| 57 | .BR fork (2)), | |
| 58 | the new process is a thread group leader, | |
| 59 | and its thread group ID (the value returned by | |
| b3eb2280 | 60 | .BR getpid (2)) |
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61 | is the same as its thread ID (the value returned by |
| 62 | .BR gettid ()). | |
| 47297adb | 63 | .SH SEE ALSO |
| 76006a4a | 64 | .BR capget (2), |
| fea681da | 65 | .BR clone (2), |
| 76006a4a | 66 | .BR fcntl (2), |
| fea681da | 67 | .BR fork (2), |
| 76006a4a | 68 | .BR get_robust_list (2), |
| c8fb1c6d | 69 | .BR getpid (2), |
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70 | .\" .BR kcmp (2), |
| 71 | .BR ioprio_set (2), | |
| 72 | .\" .BR move_pages (2), | |
| 73 | .\" .BR migrate_pages (2), | |
| 74 | .BR perf_event_open (2), | |
| 75 | .\" .BR process_vm_readv (2), | |
| 76 | .\" .BR ptrace (2), | |
| 77 | .BR sched_setaffinity (2), | |
| 78 | .BR sched_setparam (2), | |
| 79 | .BR sched_setscheduler (2), | |
| 0ec954ee MK |
80 | .BR tgkill (2), |
| 81 | .BR timer_create (2) |