Subj : Re: warning : arg 3 of 'pthread_create' from incompatibe pointer type
To   : comp.programming.threads
From : ptjm
Date : Thu Mar 03 2005 03:22 am

In article <1109787580.066987.310380@o13g2000cwo.googlegroups.com>,
Jack <JEmoderatz@yahoo.com> wrote:

% I am a beginner, 5 days-old pthread user. I was trying to write a
% simple parallel sorting code. There are 3 nodes (2 leaves, 1 parent). 2
% leaves perform sequential quick sorting and parent node perform merge
% sort from 2 child nodes.

This doesn't describe your code.

[...]


%                 a1[i] = (int)rand(0) % MAX;

rand() doesn't take an argument. rand_r() does, although it should not be
0. You should call srand() to seed the random number generator if you
want to have different inputs each run.

% 	quickSort( a1, 0, N-1);

Here, you call quickSort from main()'s thread

% 	thread_id = pthread_create(&thread1, NULL, a2_quick, &a2);
% 
% 	pthread_join(thread1, NULL);

and here you start a thread in the back-ground, then wait for it to
finish without doing anything in the interim, so you might as well have
just called a2_quick(&a2). I suggest moving the pthread_create call
before the previous call to quickSort(), and leaving pthread_join() call
where it is.

% void a2_quick(int a2[])

The prototype of a thread function should be void *(*)(void *). You could
have
 void * a2_quick(void * a2v)
 {
    int * a2 = a2v;

     ...

-- 

Patrick TJ McPhee
North York  Canada
ptjm@interlog.com

.