Undefined reference to 'sysconf' and 'posix_memalign' (IDFGH-4268)

[GiovanniCmpaner]

Environment

• Environment type: [PlatformIO (Arduino)]
• Development Kit: [ESP32-S2-Saola-1M]
• Module or chip used: [ESP32-S2-WROOM]
• IDF version [idf-release/v4.2]
• Compiler version: [esp2020r2 8.2.0]
• Operating System: [Windows]
• Power Supply: [USB]

Problem Description

When trying to compile the MVCE below inside PlataformIO, I get undefined references to sysconf and posix_memalign.
I need those functions because of a third party library (tiny-dnn especifically).

Expected Behavior

Are those functions implemented?
What are the alternatives?

Code to reproduce this issue

#include <Arduino.h>
#include <cstdlib>
#include <thread>

void setup()
{
    void* ptr{ nullptr };
    posix_memalign( &ptr, 16, 1024 );

    long value = std::thread::hardware_concurrency();
}

void loop()
{

}

Debug Logs

Error:

[...]

Building in release mode
Linking .pio\build\esp32doit-devkit-v1\firmware.elf
c:/users/giovanni/.platformio/packages/toolchain-xtensa32s2/bin/../lib/gcc/xtensa-esp32s2-elf/8.2.0/../../../../xtensa-esp32s2-elf/bin/ld.exe: C:\Users\Giovanni\.platformio\packages\framework-arduinoespressif32\tools\sdk\esp32s2\lib\librtc.a(rtc.o)(.text.rtc_pad_gpio_wakeup+0xa9): could not decode instruction; possible configuration mismatch
c:/users/giovanni/.platformio/packages/toolchain-xtensa32s2/bin/../lib/gcc/xtensa-esp32s2-elf/8.2.0/../../../../xtensa-esp32s2-elf/bin/ld.exe: c:/users/giovanni/.platformio/packages/toolchain-xtensa32s2/bin/../lib/gcc/xtensa-esp32s2-elf/8.2.0/../../../../xtensa-esp32s2-elf/lib\libstdc++.a(thread.o):(.literal._ZNSt6thread20hardware_concurrencyEv+0x0): undefined reference to `sysconf'
c:/users/giovanni/.platformio/packages/toolchain-xtensa32s2/bin/../lib/gcc/xtensa-esp32s2-elf/8.2.0/../../../../xtensa-esp32s2-elf/bin/ld.exe: c:/users/giovanni/.platformio/packages/toolchain-xtensa32s2/bin/../lib/gcc/xtensa-esp32s2-elf/8.2.0/../../../../xtensa-esp32s2-elf/lib\libstdc++.a(thread.o): in function `std::thread::hardware_concurrency()':
/builds/idf/crosstool-NG/.build/HOST-x86_64-w64-mingw32/xtensa-esp32s2-elf/src/gcc/libstdc++-v3/src/c++11/thread.cc:177: undefined reference to `sysconf'
c:/users/giovanni/.platformio/packages/toolchain-xtensa32s2/bin/../lib/gcc/xtensa-esp32s2-elf/8.2.0/../../../../xtensa-esp32s2-elf/bin/ld.exe: .pio\build\esp32doit-devkit-v1\src\main.cpp.o:(.literal._Z5setupv+0x0): undefined reference to `posix_memalign'
c:/users/giovanni/.platformio/packages/toolchain-xtensa32s2/bin/../lib/gcc/xtensa-esp32s2-elf/8.2.0/../../../../xtensa-esp32s2-elf/bin/ld.exe: .pio\build\esp32doit-devkit-v1\src\main.cpp.o: in function `setup()':
C:\Users\Giovanni\Desktop\auto2teste/src/main.cpp:8: undefined reference to `posix_memalign'
collect2.exe: error: ld returned 1 exit status
*** [.pio\build\esp32doit-devkit-v1\firmware.elf] Error 1
===================================================================== [FAILED] Took 11.54 seconds =====================================================================
The terminal process "C:\Users\Giovanni\.platformio\penv\Scripts\pio.exe 'run'" terminated with exit code: 1.

Other items

platformio.ini:

[env:esp32doit-devkit-v1]
platform_packages = platformio/framework-arduinoespressif32 @ https://github.com/espressif/arduino-esp32.git#idf-release/v4.2
platform = espressif32
board = esp32doit-devkit-v1
framework = arduino

monitor_speed = 115200
board_build.speed = 921600
board_build.partitions = partitions_custom.csv
board_build.mcu = esp32s2

build_unflags = -std=gnu++11 -fno-rtti
build_flags = -std=gnu++14 -DCORE_DEBUG_LEVEL=5

[...]

Terminal output infos:

Processing esp32doit-devkit-v1 (platform: espressif32; board: esp32doit-devkit-v1; framework: arduino)
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------Verbose mode can be enabled via `-v, --verbose` option
CONFIGURATION: https://docs.platformio.org/page/boards/espressif32/esp32doit-devkit-v1.html
PLATFORM: Espressif 32 (2.0.0) > DOIT ESP32 DEVKIT V1
HARDWARE: ESP32S2 240MHz, 320KB RAM, 4MB Flash
DEBUG: Current (esp-prog) External (esp-prog, iot-bus-jtag, jlink, minimodule, olimex-arm-usb-ocd, olimex-arm-usb-ocd-h, olimex-arm-usb-tiny-h, olimex-jtag-tiny, tumpa)
PACKAGES:
 - framework-arduinoespressif32 0.0.0+sha.29e3b64
 - tool-esptoolpy 1.30000.200511 (3.0.0)
 - toolchain-esp32s2ulp 1.22851.191205 (2.28.51) 
 - toolchain-xtensa32s2 1.80200.200827 (8.2.0)

[...]

[aquibjamal]

Hi,
I am facing the same issue while working with tiny-cnn.

Let me know if there is any workaround for this.

With regards,
Aquib Jamal

[GiovanniCmpaner]

I made some modifications to the original: https://github.com/GiovanniCmpaner/tiny-dnn
This way, the same code base is compatible with both Windows and ESP32, which, for me, was the major selling point of tiny-dnn.
Take a look at the commit history for more details, so you can reproduce the changes on xilinx-tiny-cnn as your needs.

Also, some additional unflags and flags are needed in the platformio.ini file:

build_unflags = -fno-rtti
build_flags = -mtext-section-literals

For some insight, because of the high memory consumption of tiny-dnn, I switched to tensorflow-lite.
The serializer and deserializer can be disable for less consumption, but then the file sharing with Windows becomes a hassle to implement.

[aquibjamal]

Thank you for sharing the repository and pointing in the right direction.
I am able to compile the code as shown in your files.
I had already set the rtti flags in sdkconfig file.
I am not sure if it is connected to the same issue, but now I am getting linker error -
"hello-world.elf section .dram0.bss' will not fit in region dram0_0_seg'
region `dram0_0_seg' overflowed by 83856 bytes"

I am trying to use the IRAM_DATA_ATTR and IRAM_BSS_ATTR macros, for template class variables.
This results in the following error - "section attribute not allowed for 'm_weights'
IRAM_BSS_ATTR ap_uint m_weights[PE][TILES];"

Have you come across similar problems?

Many thanks,
Aquib

[GiovanniCmpaner]

Probably there isnt enought memory in DRAM for your variable with IRAM macro, maybe you can use std::vector to allocate it in heap at runtime.
This error specific to your project needs, try searching in google.
Good luck!

[aquibjamal]

Thank you!

[dzz10]

所以，这个问题是怎么回事，Undefined reference to 'sysconf'