Subj : Re: pthreads and semaphore - Beginer question
To   : comp.programming.threads
From : David Schwartz
Date : Fri Aug 05 2005 04:40 pm


<plinius@gmail.com> wrote in message 
news:1123264045.354491.150550@g44g2000cwa.googlegroups.com...

> lampion=(sem_t)1;

    Is that really legal? There's no 'sem_init' function you're required to 
call to initialize the semphaore?

> pthread_t thread[2];
> int status;
> pthread_attr_t attr;
>
> sem_init(&lampion,NULL,0);
>
> pthread_attr_init(&attr);
> pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_JOINABLE);
> pthread_create(&thread[0],&attr,scheduler,NULL);/*sheduler*/
> pthread_create(&thread[1],&attr,worker,NULL);/*worker*/
> pthread_join(thread[0],(void**)&status);
> pthread_join(thread[1],(void**)&status);
> pthread_exit(NULL);
> }

    Casting the pointer is ugly. Better to use a real 'void *' and pass its 
address to pthread_join, you can then cast the 'void *'. The problem is that 
a 'void *' might not be the same size or same format as an 'int'. Casting 
the address doesn't give the compiler the ability to fix that.

    DS

.