[Mesa-dev] [PATCH 2/3] mapi/u_thread: Use GetCurrentThreadId
jfonseca at vmware.com
jfonseca at vmware.com
Mon Mar 3 13:41:07 PST 2014
From: José Fonseca <jfonseca at vmware.com>
u_thread_self() expects thrd_current() to return a unique numeric ID
for the current thread, but this is not feasible on Windows.
---
src/mapi/u_thread.h | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/src/mapi/u_thread.h b/src/mapi/u_thread.h
index ba5d98e..3e18358 100644
--- a/src/mapi/u_thread.h
+++ b/src/mapi/u_thread.h
@@ -89,10 +89,28 @@ typedef mtx_t u_mutex;
#define u_mutex_lock(name) (void) mtx_lock(&(name))
#define u_mutex_unlock(name) (void) mtx_unlock(&(name))
+
static INLINE unsigned long
u_thread_self(void)
{
+ /*
+ * XXX: Callers of u_thread_self assume it is a lightweight function,
+ * returning a numeric value. But unfortunately C11's thrd_current() gives
+ * no such guarantees. In fact, it's pretty hard to have a compliant
+ * implementation of thrd_current() on Windows with such characteristics.
+ * So for now, we side-step this mess and use Windows thread primitives
+ * directly here.
+ *
+ * FIXME: On the other hand, u_thread_self() and _glthread_GetID() are bad
+ * abstractions. Even with pthreads, there is no guarantee that
+ * pthread_self() will return numeric IDs -- we should be using
+ * pthread_equal() instead of assuming we can compare thread ids...
+ */
+#ifdef _WIN32
+ return GetCurrentThreadId();
+#else
return (unsigned long) (uintptr_t) thrd_current();
+#endif
}
--
1.8.5.3
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