ESP32 Forum

I got a message through event handle and I wanna send it through queue.
I know the queue will copy memory in FreeRTOS but the msg.data is a pointer so the memory that the pointer points will not be copied.
I wanna know what time the pointer will be free ? Should I copy the memory that the pointer points manually and free it after queue send.

It won't be, not by FreeRTOS that is. If you push a pointer into a queue, FreeRTOS will just handle it as it would handle any opaque data, it doesn't know it's a pointer. You would normally free it after you receive it and are done with it.

ESP_Sprite wrote: ↑

Fri Aug 16, 2024 3:41 am

It won't be, not by FreeRTOS that is. If you push a pointer into a queue, FreeRTOS will just handle it as it would handle any opaque data, it doesn't know it's a pointer. You would normally free it after you receive it and are done with it.

What I mean is, the MQTT message I get through the event function (from MQTT), its data is a pointer, I send this message through the queue, then the data memory will not be copied, do I need to copy this memory to avoid it being released by the MQTT task? My question is about the life cycle of data in MQTT messages, not freertos

Ah, gotcha. Generally you cannot assume the lifetime of any data passed into a callback exists past the duration of a callback; the documentation will explicitly mention it if it does persist longer.

ESP_Sprite wrote: ↑

Sat Aug 17, 2024 5:45 am

Ah, gotcha. Generally you cannot assume the lifetime of any data passed into a callback exists past the duration of a callback; the documentation will explicitly mention it if it does persist longer.

Got it! Thanks for ur response.

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