# RTC_SetAlarmParamAsync

## C Specification

  `#include <nitro/rtc.h>`

      RTCResult RTC_SetAlarmParamAsync(
      RTCAlarmChan	chan,
      const RTCAlarmParam*    param,
      RTCCallback		callback,
      void*        arg );

## Arguments

chan | Uses `RTCAlarmChan` to specify the alarm channel.
param | Pointer to `RTCAlarmParam` containing parameters to set.
callback | Pointer to the callback function This callback is called from within the interrupt handler.
arg | The argument to be passed to the Callback function.

## Return Values

If the request succeeds, it returns 0.
If the request fails, it returns some numeric value other than 0.

## Description

Asynchronously writes alarm interrupt parameter values to the real time clock. This function sends alarm interrupt data to ARM7 and returns the process result without waiting for a response from the processor. To get the result from the processor, you must use the `result` argument. If this function fails, no operation is performed and no user callback function is called.

## Caution

Do not define parameter values of nonexistent days of the week or times. Values are set to the RTC as specified by the `param` argument asynchronously with respect to the function. Do not use this variable for anything else until a user callback function confirms the completion of this asynchronous operation. Unless the RTC alarm interrupt permission status is `permit`, it is not possible to write parameter values to the real time clock, causing any attempted call of this function to fail.

## See Also

`RTC_SetAlarmParam`, `RTC_GetAlarmParam`, `RTC_GetAlarmParamAsync`, `RTCResult`, `RTCAlarmChan`, `RTCAlarmParam`, `RTCCallback`

## Revision History

06/27/2005 Added statement about callback being called from the interrupt handler.
03/08/2005 Standardized the use of the term 'interrupt' in Japanese.
05/18/2004 Initial version

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