diff --git a/pgrep.c b/pgrep.c
index a95bd672..36936900 100644
--- a/pgrep.c
+++ b/pgrep.c
@@ -207,8 +207,8 @@ static struct el *split_list (const char *restrict str, int (*convert)(const cha
  * contains a plain number, FALSE if there are any non-digits. */
 static int strict_atol (const char *restrict str, long *restrict value)
 {
-    int res = 0;
-    int sign = 1;
+	long res = 0;
+	long sign = 1;
 
     if (*str == '+')
         ++str;