diff --git a/src/xrt/include/xrt/xrt_defines.h b/src/xrt/include/xrt/xrt_defines.h
index fb4c47f8e..8f23afaae 100644
--- a/src/xrt/include/xrt/xrt_defines.h
+++ b/src/xrt/include/xrt/xrt_defines.h
@@ -1034,6 +1034,13 @@ enum xrt_output_name
 
 #define XRT_FREQUENCY_UNSPECIFIED 0
 
+/*!
+ * Value used as a timeout to indicate the timeout should never occur.
+ *
+ * @ingroup xrt_iface
+ */
+#define XRT_INFINITE_DURATION (0x7fffffffffffffffLL)
+
 /*!
  * A union of all output types.
  *