diff --git a/library/base64.c b/library/base64.c
index 16c254d..e468e2c 100644
--- a/library/base64.c
+++ b/library/base64.c
@@ -184,7 +184,10 @@
     }
 
     if( n == 0 )
+    {
+        *olen = 0;
         return( 0 );
+    }
 
     n = ( ( n * 6 ) + 7 ) >> 3;
     n -= j;