diff --git a/library/ringbuffer/ringbuffer.c b/library/ringbuffer/ringbuffer.c
index 76d40cd..46958ee 100644
--- a/library/ringbuffer/ringbuffer.c
+++ b/library/ringbuffer/ringbuffer.c
@@ -91,7 +91,7 @@ int rd_RingbufferSpaceLen(rd_ringbuf_t *rb)
     	iRet =  ri - wi;
     }
 
-    if (iRet > 0)
+    if (iRet >= 0)
     {
     	return iRet;
     }