diff --git a/includes/sched.h b/includes/sched.h
index 70056ba..12d9092 100644
--- a/includes/sched.h
+++ b/includes/sched.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <errno.h>
 #include <unistd.h>
 
 struct scheduler;
@@ -24,5 +25,9 @@ static inline int sched_default_threads() {
  */
 int sched_init(int nthreads, int qlen, taskfunc f, void *closure);
 
-/* Enfile une nouvelle tâche (f, closure) à l'ordonanceur (s) */
+/* Enfile une nouvelle tâche (f, closure) à l'ordonanceur (s)
+ *
+ * Peut renvoyer -1 avec errno = EAGAIN quand on dépasse la capacité de
+ * l'ordonanceur.
+ * */
 int sched_spawn(taskfunc f, void *closure, struct scheduler *s);
diff --git a/src/sched.c b/src/sched.c
index 2dc1215..cbf856b 100644
--- a/src/sched.c
+++ b/src/sched.c
@@ -1 +1,9 @@
 #include "../includes/sched.h"
+
+int sched_init(int nthreads, int qlen, taskfunc f, void *closure) {
+  return -1;
+}
+
+int sched_spawn(taskfunc f, void *closure, struct scheduler *s) {
+  return -1;
+}