diff --git a/functional_market/Fundamentals/toolbox.c b/functional_market/Fundamentals/toolbox.c
index c1647bf..9a9bc5d 100644
--- a/functional_market/Fundamentals/toolbox.c
+++ b/functional_market/Fundamentals/toolbox.c
@@ -5,8 +5,11 @@
 #include <stdlib.h>
 struct array *sort(struct array *arr, comparator f)
 {
-
+    if(!arr || !f) return NULL;
+    
     void *temp = malloc(arr->elem_size);
+    if(!temp) return NULL;
+
     if (arr->len > 0) {
         for(size_t index1 = 0; index1 < arr->len - 1; index1 ++ ){
 
@@ -30,7 +33,9 @@ struct array *sort(struct array *arr, comparator f)
 }
 
 struct array *map(struct array *arr, size_t output_size, mapper f)
-{ 
+{
+    if(!arr || !f)return NULL;
+
     void *data = calloc(arr->len, output_size);   
     if(!data) return NULL;
 
@@ -52,6 +57,8 @@ struct array *map(struct array *arr, size_t output_size, mapper f)
 
 struct array *filter(struct array *arr, predicate f)
 {
+    if(!arr || !f) return NULL;
+
     size_t index = 0;
     int flon = 0;
     while(index != arr->len){
@@ -66,8 +73,8 @@ struct array *filter(struct array *arr, predicate f)
     index = 0;
     void *data1 = calloc(flon, arr->elem_size);
     if(!data1 && flon > 0) return NULL;
+    
     size_t index2 = 0;
-
     while(index != arr->len){
         void *cur = arr->data + index * arr->elem_size;
 
@@ -88,6 +95,8 @@ struct array *filter(struct array *arr, predicate f)
 
 void *reduce(struct array *arr, void *start_value, reducer f)
 {
+    if(!arr || !start_value || !f) return NULL;
+
     void *rslt = start_value;
     size_t index = 0;
 
@@ -103,6 +112,7 @@ void *reduce(struct array *arr, void *start_value, reducer f)
 
 void foreach(struct array *arr, acceptor f)
 {
+    if(!arr || !f) return;
 // arr.data est un array de x valeurs
     size_t index = 0;