# RTC_GetAlarmParamAsync

## Syntax

  `#include <nitro/rtc.h>`

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

## Arguments

chan | Uses `RTCAlarmChan` to specify the alarm channel.
param | Pointer to `RTCAlarmParam`.
callback | Pointer to the callback function. This callback is called from within the interrupt handler.
arg | Argument to pass to the callback function.

## Return Values

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

## Description

This function asynchronously reads the alarm interrupt parameter values from the real-time clock. It queries ARM7 for the values of the alarm interrupt parameters and returns those values 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.

## Note

If the RTC alarm interrupt permission status is not "permit," the function will not be able to read the parameter values from the real-time clock. Therefore, even if this function succeeds, a "process failed" result will be passed to the user callback function. Also, the value is written asynchronously to the buffer specified with the `param` argument, so do not use this for another purpose until the completion of the asynchronous process is confirmed with the user callback function.

## See Also

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

## Revision History

2005/06/27 Added a statement about callbacks being invoked from the interrupt handler.
2005/03/08 Standardized use of the term "interrupt" in Japanese.
2004/05/18 Initial version.

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