# OS_InitIrqTable

## Syntax

  `#include <nitro/os.h>`
  `void OS_InitIrqTable( void );`

## Arguments

None.

## Return Values

None.

## Description

This function initializes the IRQ interrupt table.

The IRQ interrupt table is a table that is used to register which functions to jump to when an IRQ interrupt occurs. The table is divided along each IRQ interrupt cause.

Once this function has been called to initialize the table, functions that do nothing in response to most interrupts will have been set; however, `DMA`, `NEW DMA`, and `TIMER` interrupts register interrupt handlers that are prepared on the OS side. If the user registers a handler for these interrupts, these interrupts will be called from the interrupt handler provided by OS. The user does not need to be aware of this difference. Immediately after `OS_InitIrqTable()` is called, it should appear as though nothing is being done for any of the interrupts.

Since this function is called from within `OS_Init()`, there is no need to call it when `OS_Init()` is called.

## See Also

`OS_SetIrqFunction`, `OS_GetIrqFunction`

## Revision History

2005/07/19 Added description of calling from `OS_Init()`.
2005/03/08 Standardized the Japanese word for "interrupt."
2004/03/01 Updated description of operation at initialization.
2003/12/01 Initial version.

CONFIDENTIAL