... returns, thethread exits. On GNU /Linux, thread functions take a single parameter, of type void*,and have a void* return type.The parameter is the thread argument: GNU /Linux passesthe value along ... same memory space, thread-specific data may not beaccessed using normal variable references. GNU /Linux provides special functions forsetting and retrieving values from the thread-specific data ... second argument to pthread_key_t is acleanup function. If you pass a function pointer here, GNU /Linux automatically callsthat function when each thread exits, passing the thread-specific value...