#define MX_COMMAND(idx,cmd) ((mx_t*) MailboxFormats->data[idx])->cmd
#define MX_IDX(idx) (idx >= 0 && idx < MailboxFormats->length)
#define MX_COMMAND(idx,cmd) ((mx_t*) MailboxFormats->data[idx])->cmd
#define MX_IDX(idx) (idx >= 0 && idx < MailboxFormats->length)