diff --git a/slibs.h b/slibs.h
index 9586184..00ebd01 100644
--- a/slibs.h
+++ b/slibs.h
@@ -141,10 +141,10 @@ typedef sl_vec(char) sl_string;
 
 #define sl_str_free(str) sl_vec_free(str)
 
-const char* sl_c_str(sl_string str);
+char* sl_c_str(sl_string str);
 
 #ifdef SL_IMPLEMENTATION
-const char* sl_c_str(sl_string str) {
+char* sl_c_str(sl_string str) {
   sl_vec_push(str, '\0');
   str.size--;
   return str.data;