diff --git a/src/eval.c b/src/eval.c
index b31ed35..d8a9e43 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -7414,7 +7414,7 @@
     {
 	case VAR_NUMBER:
 	    vim_snprintf((char *)buf, NUMBUFLEN, "%lld",
-					    (long long)varp->vval.v_number);
+					    (long_long_T)varp->vval.v_number);
 	    return buf;
 	case VAR_FUNC:
 	case VAR_PARTIAL: