Quality RTOS & Embedded Software

 Real time embedded FreeRTOS RSS feed 
Quick Start Supported MCUs PDF Books Trace Tools Ecosystem

[Timer API]

 TickType_t xTimerGetExpiryTime( TimerHandle_t xTimer );

Returns the time at which the software timer will expire, which is the time at which the timer's callback function will execute.

If the value returned by xTimerGetExpiryTime() is less than the current time then the timer will expire after the tick count has overflowed and wrapped back to 0. Overflows are handled in the RTOS implementation itself, so a timer's callback function will execute at the correct time whether it is before or after the tick count overflows.

xTimer   The timer being queried.
If the timer referenced by xTimer is active, then the time at which the timer will next expire is returned (which may be after the current tick count has overflowed, see the notes above).

If the timer referenced by xTimer is not active then the return value is undefined.

Example usage:

static void prvAFunction( TimerHandle_t xTimer )
TickType_t xRemainingTime;

    /* Calculate the time that remains before the timer referenced by xTimer
    expires.  TickType_t is an unsigned type, so the subtraction will result in
    the correct answer even if the timer will not expire until after the tick
    count has overflowed. */
    xRemainingTime = xTimerGetExpiryTime( xTimer ) - xTaskGetTickCount();

[ Back to the top ]    [ About FreeRTOS ]    [ Privacy ]    [ Sitemap ]    [ ]

Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.

Latest News

NXP tweet showing LPC5500 (ARMv8-M Cortex-M33) running FreeRTOS.

Meet Richard Barry and learn about running FreeRTOS on RISC-V at FOSDEM 2019

Version 10.1.1 of the FreeRTOS kernel is available for immediate download. MIT licensed.

View a recording of the "OTA Update Security and Reliability" webinar, presented by TI and AWS.


FreeRTOS and other embedded software careers at AWS.

FreeRTOS Partners

ARM Connected RTOS partner for all ARM microcontroller cores

Espressif ESP32

IAR Partner

Microchip Premier RTOS Partner

RTOS partner of NXP for all NXP ARM microcontrollers


STMicro RTOS partner supporting ARM7, ARM Cortex-M3, ARM Cortex-M4 and ARM Cortex-M0

Texas Instruments MCU Developer Network RTOS partner for ARM and MSP430 microcontrollers

OpenRTOS and SafeRTOS

Xilinx Microblaze and Zynq partner