Index: lib/fuzzer/afl/afl_driver.cpp
===================================================================
--- lib/fuzzer/afl/afl_driver.cpp
+++ lib/fuzzer/afl/afl_driver.cpp
@@ -305,6 +305,19 @@
   return 0;
 }
 
+static int set_iterations(int *N, const char *arg) {
+  char *err;
+  long NL = strtol(arg, &err, 10);
+  if (NL < 1 || NL > INT_MAX || *err != '\0') {
+    fprintf(stderr, "WARNING: iterations invalid `%s`\n",
+        err);
+    return -1;
+  } else {
+    *N = (int)NL;
+    return 0;
+  }
+}
+
 int main(int argc, char **argv) {
   fprintf(stderr,
       "======================= INFO =========================\n"
@@ -331,8 +344,8 @@
 
   int N = 1000;
   if (argc == 2 && argv[1][0] == '-')
-      N = atoi(argv[1] + 1);
-  else if(argc == 2 && (N = atoi(argv[1])) > 0)
+    set_iterations(&N, argv[1] + 1);
+  else if(argc == 2 && (set_iterations(&N, argv[1])) == 0)
       fprintf(stderr, "WARNING: using the deprecated call style `%s %d`\n",
               argv[0], N);
   else if (argc > 1)