# CARD_UnlockBackup

## C Specification

  `#include <nitro/card.h>`
  `void CARD_UnlockBackup(u16 lock_id);`

## Arguments

lock_id | ID used for locking a card

## Return Values

None.

## Description

This function frees the access bus to the CARD backup device. If another module (with another ID) is already waiting for the bus to unlock, access rights go to the waiting module. If the specified ID is not currently locked, nothing happens.
This function always succeeds. After the access bus unlocks, it returns control.

## Caution

All functions that access a CARD backup device must first lock the access bus.
You cannot access a CARD ROM device and a backup device simultaneously.
While one bus is locked, other bus locks are forced to wait.

## See Also

`OS_UnlockCard`, `OS_UnlockCartridge`, `CARD_LockBackup`

## Revision History

09/06/2004 Added the description for the prototype.
08/31/2004 Added the description of function always succeeding.
07/23/2004 Changed lock ID type from u32 to u16.
07/13/2004 Addition concerning exclusive control of CARD ROM device and backup device
07/10/2004 Initial version.