X-Git-Url: https://pd.if.org/git/?p=pdclib;a=blobdiff_plain;f=platform%2Fwin32%2Ffunctions%2Fthreads%2Fmtx_lock.c;h=59e716dc0232c0f56e3584b1d867705e1dcbbf64;hp=70af8ae35bd7cd65c7785527544d7cf7778e2776;hb=3b357986c8ac26f3aee1033c49c28f58c3cd2fb4;hpb=3979dd45fb1088cc27bcde72f0d4a51c80035e4f

diff --git a/platform/win32/functions/threads/mtx_lock.c b/platform/win32/functions/threads/mtx_lock.c
index 70af8ae..59e716d 100644
--- a/platform/win32/functions/threads/mtx_lock.c
+++ b/platform/win32/functions/threads/mtx_lock.c
@@ -11,21 +11,15 @@ int mtx_lock(mtx_t *mtx)
         return thrd_success;
     }
 
-    DWORD res = InterlockedIncrement(&mtx->_State);
-    if(res == 0) {
-        mtx->_ThreadId = myId;
-        return thrd_success;
+    for(;;) {
+        LONG prev = InterlockedCompareExchange(&mtx->_ThreadId, myId, 0);
+        if(prev == 0)
+            return thrd_success;
+
+        DWORD rv = WaitForSingleObject(mtx->_WaitEvHandle, INFINITE);
+        if(rv != WAIT_OBJECT_0)
+            return thrd_error;
     }
-
-    // If that increment didn't leave the state == 0, then we have contention
-    //  -> block on the wait event handle
-    DWORD rv = WaitForSingleObject(mtx->_WaitEvHandle, INFINITE);
-    if(rv != WAIT_OBJECT_0) 
-        return thrd_error;
-
-    // We now own the mutex - so set it up for our use
-    mtx->_ThreadId = myId;
-    return thrd_success;
 }
 #endif