--- /dev/null
+
+/* This program checks that Helgrind reports the five degenerate
+ uses of the barrier functions shown. */
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <string.h>
+
+void* child1 ( void* arg )
+{
+ pthread_barrier_wait( (pthread_barrier_t*)arg );
+ return NULL;
+}
+
+int main ( void )
+{
+ pthread_barrier_t *bar1, *bar2, *bar3, *bar4, *bar5;
+ pthread_t thr1, thr2;
+ int r;
+
+ /* possibly set up a watchdog timer thread here. */
+
+
+
+
+
+
+
+
+
+
+
+ /* initialise a barrier with a zero count */
+ fprintf(stderr, "\ninitialise a barrier with zero count\n");
+ bar1 = malloc(sizeof(pthread_barrier_t));
+ pthread_barrier_init(bar1, NULL, 0);
+
+ /* initialise a barrier twice */
+ fprintf(stderr, "\ninitialise a barrier twice\n");
+ bar2 = malloc(sizeof(pthread_barrier_t));
+ pthread_barrier_init(bar2, NULL, 1);
+ pthread_barrier_init(bar2, NULL, 1);
+
+ /* initialise a barrier which has threads waiting on it.
+ This isn't too simple. */
+ fprintf(stderr, "\ninitialise a barrier which has threads waiting on it\n");
+ bar3 = malloc(sizeof(pthread_barrier_t));
+ pthread_barrier_init(bar3, NULL, 2);
+ /* create a thread, whose only purpose is to block on the barrier */
+ pthread_create(&thr1, NULL, child1, (void*)bar3);
+ /* guarantee that it gets there first */
+ sleep(1);
+ /* and now reinitialise */
+ pthread_barrier_init(bar3, NULL, 3);
+
+ /* destroy a barrier that has threads waiting at it */
+ fprintf(stderr, "\ndestroy a barrier that has waiting threads\n");
+ /* once again, create a thread, whose only purpose is to block. */
+ bar4 = malloc(sizeof(pthread_barrier_t));
+ pthread_barrier_init(bar4, NULL, 2);
+ /* create a thread, whose only purpose is to block on the barrier */
+ pthread_create(&thr2, NULL, child1, (void*)bar4);
+ /* guarantee that it gets there first */
+ sleep(1);
+ /* and now destroy */
+ pthread_barrier_destroy(bar4);
+
+ /* destroy a barrier that was never initialised. This is a bit
+ tricky, in that we have to fill the barrier with bytes which
+ ensure that the pthread_barrier_destroy call doesn't hang for
+ some reason. Zero-fill seems to work ok on amd64-linux (glibc
+ 2.8). */
+ fprintf(stderr, "\ndestroy a barrier that was never initialised\n");
+ bar5 = malloc(sizeof(pthread_barrier_t));
+ assert(bar5);
+ memset(bar5, 0, sizeof(*bar5));
+ pthread_barrier_destroy(bar5);
+
+ /* now we need to clean up the mess .. */
+ r= pthread_cancel(thr1); assert(!r);
+ r= pthread_cancel(thr2); assert(!r);
+
+ free(bar1); free(bar2); free(bar3); free(bar4); free(bar5);
+
+ return 0;
+}
--- /dev/null
+Thread #x was created
+ at 0x........: clone (in /...libc...)
+ by 0x........: ...
+ by 0x........: pthread_create@GLIBC_ (in /lib/libpthread...)
+ by 0x........: pthread_create@* (hg_intercepts.c:...)
+ by 0x........: barriers_and_races (pth_barrier.c:84)
+ by 0x........: main (pth_barrier.c:107)
+
+Thread #x was created
+ at 0x........: clone (in /...libc...)
+ by 0x........: ...
+ by 0x........: pthread_create@GLIBC_ (in /lib/libpthread...)
+ by 0x........: pthread_create@* (hg_intercepts.c:...)
+ by 0x........: barriers_and_races (pth_barrier.c:84)
+ by 0x........: main (pth_barrier.c:107)
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+
+Possible data race during write of size 4 at 0x........ by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...
+ This conflicts with a previous access by thread #x
+ at 0x........: threadfunc (pth_barrier.c:57)
+ by 0x........: mythread_wrapper (hg_intercepts.c:...)
+ by 0x........: ...
+ by 0x........: ...