[boost] Re: [boost.thread] Static Library support forWindows

From: Alexander Terekhov (terekhov_at_[hidden])
Date: 2004-08-06 08:04:30

Michael Glassford wrote:
[...]
> Most of the quotes apply to thread termination cleanup handlers, not tss
> cleanup handlers or whatever you call them, 

Official name is thread-specific data destructors or simply destructors.

>                                             but perhaps the same
> principles apply? 

Yep.

>                   If so, the executive summary is that I was wrong, and
> the order is specified?

If you call exit() either explicitly or by means of returning from main()
than no cleanup (pthread_cleanup_push()) handlers or TSD destructors are 
called. Now,

http://www.opengroup.org/onlinepubs/009695399/functions/pthread_exit.html

says "After all cancellation cleanup handlers have been executed, if the 
thread has any thread-specific data, appropriate destructor functions 
shall be called in an unspecified order. ... The process shall exit with 
an exit status of 0 after the last thread has been terminated. The 
behavior shall be as if the implementation called exit() with a zero 
argument at thread termination time."

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <pthread.h>

void atexit_func() {
  printf("atexit_func()\n");
}

void tsd_dtor(void * value) {
  printf("tsd_dtor(%p)\n", value);
}

void f() {
  static struct object { ~object() { printf("~object()\n"); } } o;
}

pthread_key_t key;

int main() {
  int status;
  f();
  status = atexit(&atexit_func);
  assert(!status);
  status = pthread_key_create(&key, &tsd_dtor);
  assert(!status);
  status = pthread_setspecific(key, &key);
  assert(!status);
  pthread_exit(0);
}

shall print "atexit_func()" after "tsd_dtor" and before "~object()".

And you better do NOT mess with threading stuff in atexit handlers 
and/or C++ destructors of objects with static storage duration. ;-)

regards,
alexander.