esp32-s3 board compilation error

[Abasz]

I get a linker error on esp32-s3 board (arduino espressif 3.2.0, idf 5.4.0, cpp23)

ArduinoLog/src/ArduinoLog.h:427:(.text._ZN7Logging10printLevelIPKcEEvibT_z[_ZN7Logging10printLevelIPKcEEvibT_z]+0x30): undefined reference to `_ZN7Logging8writeLogIJPK19__FlashStringHelperEEEvDpT_'
/root/.platformio/packages/toolchain-xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld: ArduinoLog/src/ArduinoLog.h:480:(.text._ZN7Logging10printLevelIPKcEEvibT_z[_ZN7Logging10printLevelIPKcEEvibT_z]+0xae): undefined reference to `_ZN7Logging8writeLogIJPKcEEEvDpT_'
/root/.platformio/packages/toolchain-xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld: ArduinoLog/src/ArduinoLog.h:454:(.text._ZN7Logging10printLevelIPKcEEvibT_z[_ZN7Logging10printLevelIPKcEEvibT_z]+0xc3): undefined reference to `_ZN7Logging8writeLogIJcEEEvDpT_'
/root/.platformio/packages/toolchain-xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld: ArduinoLog/src/ArduinoLog.h:455:(.text._ZN7Logging10printLevelIPKcEEvibT_z[_ZN7Logging10printLevelIPKcEEvibT_z]+0xce): undefined reference to `_ZN7Logging8writeLogIJPKcEEEvDpT_'
/root/.platformio/packages/toolchain-xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld: ArduinoLog/src/ArduinoLog.h:475:(.text._ZN7Logging10printLevelIPKcEEvibT_z[_ZN7Logging10printLevelIPKcEEvibT_z]+0xea): undefined reference to `_ZN7Logging8writeLogIJPKcEEEvDpT_'
/root/.platformio/packages/toolchain-xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld: ArduinoLog/src/ArduinoLog.h:433:(.text._ZN7Logging10printLevelIPKcEEvibT_z[_ZN7Logging10printLevelIPKcEEvibT_z]+0xfa): undefined reference to `_ZN7Logging8writeLogIJPKcEEEvDpT_'
/root/.platformio/packages/toolchain-xtensa-esp-elf/bin/../lib/gcc/xtensa-esp-elf/14.2.0/../../../../xtensa-esp-elf/bin/ld: ArduinoLog/src/ArduinoLog.h:430:(.text._ZN7Logging10printLevelIPKcEEvibT_z[_ZN7Logging10printLevelIPKcEEvibT_z]+0x116): undefined reference to `_ZN7Logging8writeLogIJPKcEEEvDpT_'

I think the issue is that for some reason the toolchain-riscv32-esp @ 14 links differently somhow and does not see the writeLog template definition in the cpp file.

// ArduinoLog.cpp
template<typename... Args> void Logging::writeLog(Args... args) {
    for (int i = 0; i < _handlerCount; i++) {
        if (_logOutputs[i]) {
            _logOutputs[i]->print(args...);
        }
    }
}

If I move the writeLog within the class in declaration file compilation works.

// ArduinoLog.h
// ... 
private:

    template<typename... Args>
    void writeLog(Args... args) {
        for (int i = 0; i < _handlerCount; i++) {
            if (_logOutputs[i]) {
                _logOutputs[i]->print(args...);
            }
        }
    }
//...

[Abasz]

I did some test and I realised that the issue presents because I use more aggressive optimisation (-O3) instead of the default -Os and the under lighter optimisations the compiler happens to instantiate it and pull it in, but once I turn on aggressive inlining/section‐merging (-O3), the compiler never emits a strong definition, so I get a linker error.

The solution is clearly moving the definition into the header. I created a pull request for this.