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/* This testcase is part of GDB, the GNU debugger.
Copyright 2018 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#define NUM_THREADS 4
/* Crude spin lock. Threads all spin until this is set to 0. */
int go = 1;
/* Thread function, just spin until GO is set to 0. */
void *
perform_work (void *argument)
{
/* Cast to volatile to ensure that ARGUMENT is loaded each time around
the loop. */
while (*((volatile int*) argument))
{
/* Nothing. */
}
return NULL;
}
/* The spin loop for the main thread. */
void
function (void)
{
(void) perform_work (&go);
printf ("Finished from function\n");
}
/* Main program, create some threads which all spin waiting for GO to be
set to 0. */
int
main (void)
{
pthread_t threads[NUM_THREADS];
int result_code;
unsigned index;
/* Create some threads. */
for (index = 0; index < NUM_THREADS; ++index)
{
printf ("In main: creating thread %d\n", index);
result_code = pthread_create (&threads[index], NULL, perform_work, &go);
assert (!result_code);
}
function ();
/* Wait for each thread to complete. */
for (index = 0; index < NUM_THREADS; ++index)
{
/* Block until thread INDEX completes. */
result_code = pthread_join (threads[index], NULL);
assert (!result_code);
printf ("In main: thread %d has completed\n", index);
}
printf ("In main: All threads completed successfully\n");
return 0;
}
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