The FreeRTOS kernel is now an MIT licensed AWS open source project, and these pages are being updated accordingly.

Quality RTOS & Embedded Software

About Contact Support FAQ Download

Menu

Quick Start

Supported MCUs

PDF Books

Trace Tools

Ecosystem

Quick Start Guide

Support Forum

⇓ Download Source ⇓

FreeRTOS+ Ecosystem

FreeRTOS+TCP:
Thread safe TCP/IP stack

SafeRTOS:
TUV certified RTOS

OpenRTOS:
Commercial Licensed RTOS

Fail Safe File System:
Ensures data integrity

FreeRTOS BSPs:
3rd party driver packages

Trace & Visualisation:
Tracealyzer for FreeRTOS

CLI:
Command line interface

WolfSSL SSL / TLS:
Networking security protocols

RTOS Training:
Delivered online or on-site

IO:
read(), write(), ioctl() interface

FreeRTOS+ Lab Projects

FreeRTOS+POSIX:
POSIX threading API

FreeRTOS+FAT:
Thread aware file system

xTimerGetExpiryTime
[Timer API]

timers.h

 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.

Parameters:

xTimer

The timer being queried.

Returns:: 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();
}