# OS_GetTick

## Syntax

      #include <nitro/os.h>

      OSTick OS_GetTick( void );

## Arguments

None.

## Return Values

The tick value.

## Description

Acquires a tick value. `OSTick` tick values are of type `u64`.

Ticks must be initialized with the `OS_InitTick` function before calling this function.

Internally, this function creates a tick value from the 16-bit timer counter value and the timer's interrupt count counter. Accordingly, if interrupts are disabled for a long period (at least 65536 * `OS_SYSTEM_CLOCK`/64 Hz, or approximately 7.5 frames) the counter will fail to advance, and the difference between the tick values before and after that period will be inconsistent.

## See Also

`OS_InitTick, OS_SetTick, OS_GetTickLo`

## Revision History

2005/04/18 Added warning about disabling interrupts for long periods.
2004/02/25 Changed systemClock -> tick.
2004/02/23 Changed the system clock value to a full 64-bit.
2004/02/04 Initial version.

CONFIDENTIAL