diff --git a/src/interfaces/ecpg/preproc/preproc.y b/src/interfaces/ecpg/preproc/preproc.y
index bbb1e785b4..274d4b64a0 100644
--- a/src/interfaces/ecpg/preproc/preproc.y
+++ b/src/interfaces/ecpg/preproc/preproc.y
@@ -3355,7 +3355,7 @@ Character:  character '(' Iconst ')'
 						yyerror(errortext);
 					}
 					else if (atol($3) > MaxAttrSize) {
-						sprintf(errortext, "length for type '%s' cannot exceed %d",$1,MaxAttrSize);
+						sprintf(errortext, "length for type '%s' cannot exceed %ld",$1,(long) MaxAttrSize);
 						yyerror(errortext);
 					}