man3/pthread_exit.3

   1 .\" Copyright (c) 2008 Linux Foundation, written by Michael Kerrisk
   2 .\"     <mtk.manpages@gmail.com>
   3 .\"
   4 .\" SPDX-License-Identifier: Linux-man-pages-copyleft
   5 .\"
   6 .TH PTHREAD_EXIT 3 2021-03-22 "Linux man-pages (unreleased)" "Linux Programmer's Manual"
   7 .SH NAME
   8 pthread_exit \- terminate calling thread
   9 .SH LIBRARY
  10 POSIX threads library
  11 .RI ( libpthread ", " \-lpthread )
  12 .SH SYNOPSIS
  13 .nf
  14 .B #include <pthread.h>
  15 .PP
  16 .BI "noreturn void pthread_exit(void *" retval );
  17 .fi
  18 .SH DESCRIPTION
  19 The
  20 .BR pthread_exit ()
  21 function terminates the calling thread and returns a value via
  22 .I retval
  23 that (if the thread is joinable)
  24 is available to another thread in the same process that calls
  25 .BR pthread_join (3).
  26 .PP
  27 Any clean-up handlers established by
  28 .BR pthread_cleanup_push (3)
  29 that have not yet been popped,
  30 are popped (in the reverse of the order in which they were pushed)
  31 and executed.
  32 If the thread has any thread-specific data, then,
  33 after the clean-up handlers have been executed,
  34 the corresponding destructor functions are called,
  35 in an unspecified order.
  36 .PP
  37 When a thread terminates,
  38 process-shared resources (e.g., mutexes, condition variables,
  39 semaphores, and file descriptors) are not released,
  40 and functions registered using
  41 .BR atexit (3)
  42 are not called.
  43 .PP
  44 After the last thread in a process terminates,
  45 the process terminates as by calling
  46 .BR exit (3)
  47 with an exit status of zero;
  48 thus, process-shared resources
  49 are released and functions registered using
  50 .BR atexit (3)
  51 are called.
  52 .SH RETURN VALUE
  53 This function does not return to the caller.
  54 .SH ERRORS
  55 This function always succeeds.
  56 .SH ATTRIBUTES
  57 For an explanation of the terms used in this section, see
  58 .BR attributes (7).
  59 .ad l
  60 .nh
  61 .TS
  62 allbox;
  63 lbx lb lb
  64 l l l.
  65 Interface       Attribute       Value
  66 T{
  67 .BR pthread_exit ()
  68 T}      Thread safety   MT-Safe
  69 .TE
  70 .hy
  71 .ad
  72 .sp 1
  73 .SH STANDARDS
  74 POSIX.1-2001, POSIX.1-2008.
  75 .SH NOTES
  76 Performing a return from the start function of any thread other
  77 than the main thread results in an implicit call to
  78 .BR pthread_exit (),
  79 using the function's return value as the thread's exit status.
  80 .PP
  81 To allow other threads to continue execution,
  82 the main thread should terminate by calling
  83 .BR pthread_exit ()
  84 rather than
  85 .BR exit (3).
  86 .PP
  87 The value pointed to by
  88 .I retval
  89 should not be located on the calling thread's stack,
  90 since the contents of that stack are undefined after the thread terminates.
  91 .SH BUGS
  92 Currently,
  93 .\" Linux 2.6.27
  94 there are limitations in the kernel implementation logic for
  95 .BR wait (2)ing
  96 on a stopped thread group with a dead thread group leader.
  97 This can manifest in problems such as a locked terminal if a stop signal is
  98 sent to a foreground process whose thread group leader has already called
  99 .BR pthread_exit ().
 100 .\" FIXME . review a later kernel to see if this gets fixed
 101 .\" http://thread.gmane.org/gmane.linux.kernel/611611
 102 .\" http://marc.info/?l=linux-kernel&m=122525468300823&w=2
 103 .SH SEE ALSO
 104 .BR pthread_create (3),
 105 .BR pthread_join (3),
 106 .BR pthreads (7)