From 6a4085ee02ab8bc5fa4388cede4ee73c1994567f Mon Sep 17 00:00:00 2001
From: bje <bje>
Date: Sun, 19 Jul 1998 12:13:12 +0000
Subject: 1998-07-19  Ben Elliston  <bje@cygnus.com>

	* mutex.c (pthread_mutex_trylock): Return ENOSYS if this function
	is called on a Win32 platform which is not Windows NT.
---
 mutex.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

(limited to 'mutex.c')

diff --git a/mutex.c b/mutex.c
index 6d425ab..da8737a 100644
--- a/mutex.c
+++ b/mutex.c
@@ -147,9 +147,15 @@ pthread_mutex_unlock(pthread_mutex_t *mutex)
 int
 pthread_mutex_trylock(pthread_mutex_t *mutex)
 {
-  /* This only works on Windows NT 4.0 and above.  If this function is
-     called from Windows 95, we must return ENOSYS. */
-     
+  /* Typically evaluates to 31. */
+  int numbits = (sizeof(DWORD) * 8) - 1;
+
+  if ((GetVersion() >> numbits) != 1)
+    {
+      /* We're not on Windows NT; return ENOSYS. */
+      return ENOSYS;
+    }
+      
   if (mutex == NULL)
     {
       return EINVAL;
-- 
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