configASSERT() for development debugging in FreeRTOS

Introduction

configASSERT() helps catch mistakes early by stopping the program when something unexpected happens. It is like a safety net during development to find bugs quickly.

When you want to check if a pointer is not NULL before using it.

When you want to verify that a variable has a valid value during program execution.

When you want to catch errors in task creation or resource allocation.

When you want to make sure assumptions in your code are true while testing.

When you want to stop the program immediately if something goes wrong to debug easily.

Syntax

FreeRTOS

configASSERT( condition );

The condition is an expression that should be true for the program to continue.

If condition is false, the program will stop (usually in an infinite loop) to help you find the problem.

Examples

Check that pointer x is not NULL before using it.

FreeRTOS

configASSERT( x != NULL );

Ensure the queue is not full before adding a new message.

FreeRTOS

configASSERT( uxQueueMessagesWaiting(queue) < QUEUE_LENGTH );

Verify that a task was created successfully.

FreeRTOS

configASSERT( taskHandle != NULL );

Sample Program

This program creates a task that uses configASSERT() to check if the pointer passed to the task is not NULL. If the pointer is NULL, the program will stop, helping you find the bug early.

FreeRTOS

#include "FreeRTOS.h"
#include "task.h"
#include <stdio.h>

void vTaskFunction(void *pvParameters) {
    int *ptr = (int *)pvParameters;
    configASSERT(ptr != NULL);  // Check pointer is valid

    printf("Value pointed to: %d\n", *ptr);
    vTaskDelete(NULL);
}

int main(void) {
    int value = 42;
    xTaskCreate(vTaskFunction, "Task1", configMINIMAL_STACK_SIZE, &value, 1, NULL);
    vTaskStartScheduler();
    return 0;
}

Important Notes

configASSERT() is usually enabled only in development builds to avoid slowing down the final product.

If configASSERT() fails, the program typically enters an infinite loop to halt execution for debugging.

You can customize the behavior of configASSERT() by defining your own assert handler in FreeRTOSConfig.h.

Summary

configASSERT() helps catch bugs early by stopping the program when a condition is false.

Use it to check pointers, task creation, and other important assumptions during development.

It improves debugging by making errors obvious and easy to find.