Re: [RFA/TESTSUITE] build schedlock.c on 64-bit platforms

[Elena Zannoni <ezannoni@redhat.com>]

Daniel Jacobowitz writes:
 > On Thu, Apr 10, 2003 at 05:16:05PM +0200, Andreas Schwab wrote:
 > > Andrew Cagney <ac131313@redhat.com> writes:
 > > 
 > > |> >  	args[i] = 1;
 > > |> >> -	res = pthread_create(&threads[i], NULL, thread_function, (void *)i);
 > > |> >> 
 > > |> 
 > > |> Try:
 > > |> 
 > > |>   (((char *) NULL) + i)
 > > |> 
 > > |> and what ever the reverse of that is ....
 > > 
 > > That is even less portable than the above.
 > 
 > Really?  What's non-portable about it?


Attempt #3....

Index: schedlock.c
===================================================================
RCS file: /cvs/uberbaum/gdb/testsuite/gdb.threads/schedlock.c,v
retrieving revision 1.2
diff -u -p -r1.2 schedlock.c
--- schedlock.c	23 Oct 2002 03:22:56 -0000	1.2
+++ schedlock.c	10 Apr 2003 16:04:37 -0000
@@ -18,18 +18,25 @@ int main() {
     for (i = 0; i < NUM; i++)
       {
 	args[i] = 1;
-	res = pthread_create(&threads[i], NULL, thread_function, (void *)i);
+	res = pthread_create(&threads[i],
+		             NULL,
+			     thread_function,
+			     (void *) (((char *) NULL) + i));
       }
 
     /* schedlock.exp: last thread start.  */
     args[i] = 1;
-    thread_function ((void *) i);
+    thread_function ((void *) (((char *) NULL) + i));
 
     exit(EXIT_SUCCESS);
 }
 
 void *thread_function(void *arg) {
-    int my_number = (int) arg;
+
+ /* Use sick pointer arithmetic trick, to get an offset which is a
+    long. This will be silently converted to an int, which is of
+    smaller size on 64-bit platforms.  */
+    int my_number =  (char *) arg - (char *) NULL;
     int *myp = &args[my_number];
 
     /* Don't run forever.  Run just short of it :)  */