a POSIX incompliance issue with pthread_mutex_trylock()

I am working in the Open POSIX Test Suite project at
http://posixtest.sourceforge.net/, whose goal is to perform conformance,
functional, stress, and performance testing of POSIX APIs. When running
tests upon ngpt-2.2.0, I found an incompliance behavior.  If a thread calls
pthread_mutex_trylock() on a mutex that it already owns, the function
returns EDEADLK.  But according to the standards, only pthread_mutex_lock
should return EDEADLK, while pthread_mutex_trylock should return EBUSY
instead. 

I am posting a patch which may address this issue.

--- ngpt-2.2.0-orig/pth_sync.c	2003-01-30 09:38:57.000000000 +0800
+++ ngpt-2.2.0/pth_sync.c	2003-01-30 09:40:41.000000000 +0800
@@ -273,6 +273,8 @@
             return 0;
 	} else {
 	    _pth_release(&(mutex->mx_lock), descr->tid);
+	    if(tryonly)
+		return EBUSY;
 	    return EDEADLK;
 	}
     }
@@ -419,6 +421,8 @@
             return 0;
 	} else {
 	    _pth_release(&(mutex->mx_lock), descr->tid);
+	    if(tryonly)
+		return EBUSY;
 	    return EDEADLK;
 	}
     }

Bingwei Liu              
Software Engineer,  Intel Corporation
[email protected]

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