Find thread limit

thread-limit.c

/* gcc -lpthread -o thread-limit thread-limit.c */

#include <stdio.h>
#include <unistd.h>
#include <pthread.h>

#define MAX_THREADS 10000
int i;

void run(void) {
  char c;
  if (i < 10)
    printf("Address of c = %u KB\n", (unsigned int) &c / 1024);
  sleep(60 * 60);
}

int main(int argc, char *argv[]) {
  int rc = 0;
  pthread_t thread[MAX_THREADS];
  printf("Creating threads ...\n");
  for (i = 0; i < MAX_THREADS && rc == 0; i++) {
    rc = pthread_create(&(thread[i]), NULL, (void *) &run, NULL);
    if (rc == 0) {
      pthread_detach(thread[i]);
      if ((i + 1) % 100 == 0)
	printf("%i threads so far ...\n", i + 1);
    }
    else
      printf("Failed with return code %i creating thread %i.\n",
	     rc, i + 1);
  }
  exit(0);
}