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diff --git a/lib/glthread/thread.h b/lib/glthread/thread.h
index a04e4a4..a5f62a1 100644 (file)
--- a/lib/glthread/thread.h
+++ b/lib/glthread/thread.h
@@ -137,6 +137,9 @@ extern int glthread_in_use (void);
 
 /* -------------------------- gl_thread_t datatype -------------------------- */
 
+/* This choice of gl_thread_t assumes that
+     pthread_equal (a, b)  is equivalent to  ((a) == (b)).
+   This is the case on all platforms in use in 2008.  */
 typedef pthread_t gl_thread_t;
 # define glthread_create(THREADP, FUNC, ARG) \
     (pthread_in_use () ? pthread_create (THREADP, NULL, FUNC, ARG) : ENOSYS)