zalloc not more supported in esp-idf was there a change?

[rudi ;-)]

hi guys,

have a small problem with zalloc

Code: Select all

char *recv_buf = (char *)zalloc(512);

in ESP31 RTOS compile without problems
is there a change in esp-idf?


btw:
lwip/mem.h

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#ifndef mem_zalloc
#define mem_zalloc(s) ({const char *file = mem_debug_file; pvPortZalloc(s, file, __LINE__);})

best wishes
rudi

[kolban]

This is a wild guess ... but if ESP-IDF plans to delegate management to FreeRTOS then by the FreeRTOS docs, it appears we should use pvPortMalloc() to allocate memory and vPortFree() to free memory. It is likely pvPortZalloc() is the same as pvPortMalloc() with zero value initialization.

[ESP_igrr]

You can use calloc, which is part of C standard library.

[ESP_Sprite]

kolban: Actually, malloc, calloc etc are provided by newlib (and the current esp_idf configures them to basically use the freertos alloc structs). I don't think there's any danger in using them instead of the FreeRTOS constructs.

[kolban]

Would it be possible to describe the relationship between newlib and the other components? For example, I was reading about newlib and think this is what is meant:

http://www.sourceware.org/newlib/

Are we saying that the functions exposed by newlib can be safely used in an ESP32 ESP-IDF environment? Are there restrictions or caveats?

I see in github that newlib is distributed in binary form:

https://github.com/espressif/esp-idf/tr ... newlib/lib

Is there a reason the source is not available?

[ESP_Sprite]

Newlib indeed is the newlib you point at (or a version that has been lightly modified to compile on Xtensa, not sure, not much difference in how it works.)

We distribute newlib in binary form because the bulk of it actually is integrated in ROM. We could also distribute the bit that's linked into the flash app in source form (and maybe we will, if there's demand for it; there are no secrets there afaik) but it's not that useful because it has to be compiled with exactly the same compiler / flags / ... as the Newlib in ROM in order to work. Compiling it from source as we do with the rest of esp-idf would potentially introduce bugs when people mess with the esp-idf configuration or compiler and the interface would become incompatible.