Hi ESP_Angus,
thanks for your reply. Good to know that ESP is not using the heap definitions of free rtos. I got everything working now.

I still don't know what causes my problem in the original program but the following program works as expected although I don't even bother to check whether the pointer exists ( I kind of do with the allocation flag). I compile this in the same way as my original program that causes problems. So, I c...

Thanks for your help! Unfortunately that is not the cause as the complete code line is: if(ptr != NULL)vPortFree(ptr); . Changing to free(ptr) does not make a difference. I still try to find where the rtos heap_x.c files are included. This is from the free rtos web site https://www.freertos.org/a001...

Hello everybody, I am new here so please forgive me if the answer to my question is really obvious. For me it is not :( In a thread I allocate memory either with ptr = (char *)pvPortMalloc((digitc+1)*sizeof(char)); or with ptr = (char *)malloc(digitc*sizeof(char)); . This works OK and when I check t...