diff --git a/lib/vsnprintf.c b/lib/vsnprintf.c
index 2d68c50377403f35aedd7592ea42482e4e418b6c..618639dbb1ef8de954eaccd4656bd4f334ad61f1 100644
--- a/lib/vsnprintf.c
+++ b/lib/vsnprintf.c
@@ -1297,9 +1297,9 @@ int vsnprintf(char *str, size_t size, const char *format, va_list ap)
 
 		/* and render */
 		if (!str) /* to stdout? */
-			buf += render_specifier(NULL, NULL, format, &spec, &ap);
+			render_specifier(NULL, NULL, format, &spec, &ap);
 		else
-			buf += render_specifier(&buf, end, format, &spec, &ap);
+			render_specifier(&buf, end, format, &spec, &ap);
 
 		format++; /* the type is always a single char */
 	}