7 years, 5 months ago.

mbed OS 5 Mail::caaloc

Mail::calloc() returns with NULL even the the Queue is not full!

I use a mailbox using mbed Mail class as :

CapturedFrame *_pCapturedFrame; Mail<CapturedFrame, 8> _frameQueue;

In a TimeOut handler function I terminate the current received frame with :

rc = _frameQueue.put(_pCapturedFrame), which Returns allways with osOK! A Background thread will process this Frame and frees up the Memory block using :

rc = _frameQueue.free(pFrame), which Returns allways with osOK!

After calling Mail::put I setup my Frame pointer with a next Frame from my Memorypool as:

_pCapturedFrame = _frameQueue.calloc();

With low load it works, but when I send multiple Frames faster, then I get a NULL pointer back! I check the Queue Status, but Queue is not full - but also not empty. I tried to encapsulate with 'mbed_critical_section', nothing changed! I incrased the number of Mail entries, but this will only shift the Event some Frames later, but still happens! I would understand the returned NULL pointer when the Queue is full (means also I calloc all my Memory packets from pool), but only returning NULL I do not know what happens!

Are there any issues known?

Many Thanks