Question

I am programming with C and pthreads. I have a long running function which I want to run in a seperate thread:

void long_running_function(void * arg) {  
  ...
}


void start_long_running_function(void * arg) {  
  pthread_t thread;  
  pthread_create( &thread , NULL , long_running_function , arg);
  /* What about the thread variable? */  
}  

When leaving the start_long_running_function() function the local variable ‘thread’ will go out of scope. Is this OK – or can I risk problems e.g. when the long_running_function() is complete?

I have tried the approach illustrated in my code, and it seems to work – but maybe that is only luck?

Regards Joakim

Answer 1

Yes — it’s safe to let the variable go out of scope. But remember you have to at some point do one of two things:

1) pthread_detach() it so the kernel will free some kind of stuff that’s associated with it.

2) pthread_join() it which has as a side-effect detaching it.

If you don’t, I think this will be a resource leak.