diff --git a/library/base64.c b/library/base64.c
index c94995b..dba4c23 100644
--- a/library/base64.c
+++ b/library/base64.c
@@ -176,7 +176,10 @@
     }
 
     if( n == 0 )
+    {
+        *dlen = 0;
         return( 0 );
+    }
 
     n = ((n * 6) + 7) >> 3;
     n -= j;