Hello,
I have been experiencing a really strange problem with the combination
of pthreads and POSIX semaphores when debugged with gdb 5.0
I'm using gcc 2.95.3, I don't know the version of my pthread library, but it
came with glibc 2.2.2
I wrote the following small testprogram:
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <semaphore.h>
#include <unistd.h>
sem_t semaphore;
void *threadproc(void *arg)
{
//while (1)
//{
sem_wait(&semaphore);
printf("thread output\n");
//}
return NULL;
};
int main(int argc, char *argv[])
{
pthread_t thread;
sem_init(&semaphore,0,0);
pthread_create(&thread, NULL, threadproc, NULL);
sleep(5);
sem_post(&semaphore);
sleep(5);
printf("main output\n");
return EXIT_SUCCESS;
}
When I do
gcc main.c -lpthread
and then
gdb a.out
> run
the output stays quiet for 5 seconds (the first sleep(5)), then
I get "thread output" and "main output" immediately following
eachother, while the 'program exited normally' immediately
after printing this output.
The second 'sleep(5)' immediately seems to return.
When I compile the code with debug info, and step through
the code in main(), the execution stalls at sem_post(&semaphore),
probably because the pthread ends.
So I added a while(1) loop in the threadproc, now I can step
through the complete main function, and the second 'sleep(5)'
takes 5 seconds like it should.
(adding the while loop in the threadproc does not have any
effect on the results of the first test)
I have not been able to find anything related to this problem,
but please forgive my ignorance, because this is one of
my first experiences with gdb...
Best regards,
Pieter Grimmerink
_______________________________________________
Bug-gdb mailing list
[EMAIL PROTECTED]
http://mail.gnu.org/mailman/listinfo/bug-gdb
