diff --git a/src/stdlib/atoll.c b/src/stdlib/atoll.c
index 4a72c5e..5355305 100644
--- a/src/stdlib/atoll.c
+++ b/src/stdlib/atoll.c
@@ -3,7 +3,7 @@
 long long atoll(const char *str)
 {
     const char *start = str;
-    long long ret;
+    long long ret = 0;
 
     while (*start != '\0') {
         if (isdigit(*str))