Issue #7316: the acquire() method of lock objects in the :mod:`threading`
module now takes an optional timeout argument in seconds. Timeout support
relies on the system threading library, so as to avoid a semi-busy wait
loop.
diff --git a/Include/pythread.h b/Include/pythread.h
index dfd6157..9c93f0e 100644
--- a/Include/pythread.h
+++ b/Include/pythread.h
@@ -19,6 +19,41 @@
PyAPI_FUNC(int) PyThread_acquire_lock(PyThread_type_lock, int);
#define WAIT_LOCK 1
#define NOWAIT_LOCK 0
+
+/* PY_TIMEOUT_T is the integral type used to specify timeouts when waiting
+ on a lock (see PyThread_acquire_lock_timed() below).
+ PY_TIMEOUT_MAX is the highest usable value (in microseconds) of that
+ type, and depends on the system threading API.
+
+ NOTE: this isn't the same value as `_thread.TIMEOUT_MAX`. The _thread
+ module exposes a higher-level API, with timeouts expressed in seconds
+ and floating-point numbers allowed.
+*/
+#if defined(HAVE_LONG_LONG)
+#define PY_TIMEOUT_T PY_LONG_LONG
+#define PY_TIMEOUT_MAX PY_LLONG_MAX
+#else
+#define PY_TIMEOUT_T long
+#define PY_TIMEOUT_MAX LONG_MAX
+#endif
+
+/* In the NT API, the timeout is a DWORD and is expressed in milliseconds */
+#if defined (NT_THREADS)
+#if (0xFFFFFFFFLL * 1000 < PY_TIMEOUT_MAX)
+#undef PY_TIMEOUT_MAX
+#define PY_TIMEOUT_MAX (0xFFFFFFFFLL * 1000)
+#endif
+#endif
+
+/* If microseconds == 0, the call is non-blocking: it returns immediately
+ even when the lock can't be acquired.
+ If microseconds > 0, the call waits up to the specified duration.
+ If microseconds < 0, the call waits until success (or abnormal failure)
+
+ microseconds must be less than PY_TIMEOUT_MAX. Behaviour otherwise is
+ undefined. */
+PyAPI_FUNC(int) PyThread_acquire_lock_timed(PyThread_type_lock,
+ PY_TIMEOUT_T microseconds);
PyAPI_FUNC(void) PyThread_release_lock(PyThread_type_lock);
PyAPI_FUNC(size_t) PyThread_get_stacksize(void);