diff --git a/nxxml.c b/nxxml.c
index 3b0c01ec..524c6dca 100644
--- a/nxxml.c
+++ b/nxxml.c
@@ -862,7 +862,7 @@ static char *formatAttributeData(void *data, int datalen, int iType){
     break;
   }
   if(intData){
-    snprintf(number,79,"%s%d",type,iValue);
+    snprintf(number,79,"%s%ld",type,iValue);
   } else {
     snprintf(number,79,"%s%f",type,dValue);
   }