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Full Discussion: threading problem
Top Forums Programming threading problem Post 302286061 by Corona688 on Tuesday 10th of February 2009 09:10:01 AM
Old 02-10-2009
code tags for code please. [ code ] stuff [ /code ] without the extra spaces in the tags. It preserves spaces and makes code readable. I'm not sure the code is compilable in its current state with things like the return value for main missing.

I think you need to put pthread_exit() at the bottom of the thread. This is also where the thread's return value is passed.

Also, you did not specify the threads as joinable, hence join should not be used on them. To make them joinable:

Code:
int main()
{
        pthread_attr_t attr;
        pthread_t thread1, thread2;
        char *message1 = "Thread 1";
        char *message2 = "Thread 2";
        int iret1, iret2;

        /* Set up attributes for the threads */
        pthread_attr_init(&attr);
        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);

        /* Create independent threads each of which will execute function */

        iret1 = pthread_create( &thread1, &attr, print_message_function, (void*) message1);
        iret2 = pthread_create( &thread2, &attr, print_message_function, (void*) message2);

        /* Wait till threads are complete before main continues. Unless we */
        /* wait we run the risk of executing an exit which will terminate */
        /* the process and all threads before the threads have completed. */

        pthread_join( thread1, NULL);
        pthread_join( thread2, NULL);

        printf("Thread 1 returns: %d\n",iret1);
        printf("Thread 2 returns: %d\n",iret2);
        exit(0);
}

 

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LEARN ABOUT XFREE86

pthread_attr_setdetachstate

PTHREAD_ATTR_SETDETACHSTATE(3)				     Linux Programmer's Manual				    PTHREAD_ATTR_SETDETACHSTATE(3)

NAME

       pthread_attr_setdetachstate, pthread_attr_getdetachstate - set/get detach state attribute in thread attributes object

SYNOPSIS

       #include <pthread.h>

       int pthread_attr_setdetachstate(pthread_attr_t *attr, int detachstate);
       int pthread_attr_getdetachstate(const pthread_attr_t *attr, int *detachstate);

       Compile and link with -pthread.

DESCRIPTION

       The pthread_attr_setdetachstate() function sets the detach state attribute of the thread attributes object referred to by attr to the value
       specified in detachstate.  The detach state attribute determines whether a thread created using the thread attributes object attr  will	be
       created in a joinable or a detached state.

       The following values may be specified in detachstate:

       PTHREAD_CREATE_DETACHED
	      Threads that are created using attr will be created in a detached state.

       PTHREAD_CREATE_JOINABLE
	      Threads that are created using attr will be created in a joinable state.

       The default setting of the detach state attribute in a newly initialized thread attributes object is PTHREAD_CREATE_JOINABLE.

       The  pthread_attr_getdetachstate()  returns  the  detach  state	attribute of the thread attributes object attr in the buffer pointed to by
       detachstate.

RETURN VALUE

       On success, these functions return 0; on error, they return a nonzero error number.

ERRORS

       pthread_attr_setdetachstate() can fail with the following error:

       EINVAL An invalid value was specified in detachstate.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +-------------------------------+---------------+---------+
       |Interface		       | Attribute     | Value	 |
       +-------------------------------+---------------+---------+
       |pthread_attr_setdetachstate(), | Thread safety | MT-Safe |
       |pthread_attr_getdetachstate()  |	       |	 |
       +-------------------------------+---------------+---------+
CONFORMING TO

       POSIX.1-2001, POSIX.1-2008.

NOTES

       See pthread_create(3) for more details on detached and joinable threads.

       A  thread that is created in a joinable state should eventually either be joined using pthread_join(3) or detached using pthread_detach(3);
       see pthread_create(3).

       It is an error to specify the thread ID of a thread that was created  in  a  detached  state  in  a  later  call  to  pthread_detach(3)	or
       pthread_join(3).

EXAMPLE

       See pthread_attr_init(3).

SEE ALSO

       pthread_attr_init(3), pthread_create(3), pthread_detach(3), pthread_join(3), pthreads(7)

COLOPHON

       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux								    2017-09-15					    PTHREAD_ATTR_SETDETACHSTATE(3)
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