Avoid to destroy the memory for the argument as it is already done when the line is destroyed

src/blc_command.cpp

@@ -134,8 +134,6 @@ void blc_command_add(const char *command_name, type_blc_command_cb callback, con
     
     APPEND_ITEM(&blc_commands, &blc_commands_nb, &tmp_command);
 }
-
-/* line may be allocated indefinitly, but it does not happen often. */
 static void blc_command_interpret_block(){
     blc_mem line, parameter;
     size_t line_capability=0;
@@ -166,7 +164,7 @@ static void blc_command_interpret_block(){
             
             if (parameter.size == 0) //No text after the command
             {
-                parameter.data = NULL;
+                parameter.chars = NULL;
                 if (command->prompt != NULL) //A text was expected
                 {
                     fprintf(stderr, "%s:", command->prompt);
@@ -174,7 +172,7 @@ static void blc_command_interpret_block(){
                     parameter.chars[parameter.size]=0;
                 }
                 if (command->callback) command->callback( parameter.chars, command->user_data); //In which callback is NULL ??
-                FREE(parameter.chars);
+                parameter.~blc_mem();
                 line_capability=0;
                 break;
             }
@@ -187,6 +185,7 @@ static void blc_command_interpret_block(){
         }
     }
     if (command < blc_commands) fprintf(stderr, "Unknown command in: %s\n", line.chars);
+    parameter.chars=NULL; //Avoid to be destructed twice
 }
 
 void blc_command_interpret(){