User:Kr/exit race.c

A race between threads and the "exit" call ...

Solaris:

  > cc exit_race.c -o exit_race.bin
  > ./exit_race.bin
  main - tid: 1
  foo - tid: 2
  bar - tid: 2
  main - ad: 1
 
  Linux:
  > gcc -g exit_race.c -lpthread
  > ./exit_race.bin 
  main - tid: b7ddbac0
  foo - tid: b7ddab90
  bar - tid: b7ddab90
  main - ad: 1

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
 
#ifdef __PRETTY_FUNCTION__
#   define PFUN  __PRETTY_FUNCTION__
#else
#    define PFUN  __func__
#endif
 
static void * foo(void * gr) {
    fprintf(stderr, "%s - tid: %x\n", PFUN, pthread_self());
    sleep(5);
    exit(0);
}
 
static volatile int ad = 0;
 
#ifdef __GNUC__
static void bar(void) __attribute__((destructor));
#endif
 
static void bar(void) {
    fprintf(stderr, "%s - tid: %x\n", PFUN, pthread_self());
    ad = 1;
    sleep(5); // this just stands for some slow de-initialization
}
 
#ifdef __SUNPRO_C
# pragma fini(bar)
#endif
 
static pthread_t bt;
 
static void main_cleanup(void * gr) {
    fprintf(stderr, "%s - tid: %x\n", PFUN, pthread_self());
}
 
int main() {
    fprintf(stderr, "%s - tid: %x\n", PFUN, pthread_self());
    pthread_create(&bt, NULL, foo, NULL);
    while (!ad) ; // Busy wait for ad to change!
    fprintf(stderr, "%s - ad: %i\n", PFUN, ad);
    pthread_exit(NULL);
}