diff --git a/library/base64.c b/library/base64.c
index d3814d6..0c6b46c 100644
--- a/library/base64.c
+++ b/library/base64.c
@@ -82,7 +82,10 @@
     unsigned char *p;
 
     if( slen == 0 )
+    {
+        *dlen = 0;
         return( 0 );
+    }
 
     n = ( slen << 3 ) / 6;