C++ compiler has issues with developer scoped functions being passed as void* to the eUI object array

[Scottapotamas]

C++ compiler has issues with developer scoped functions being passed as void* to the eUI object array

[Scottapotamas]

Legitimately not sure if this is doable with a strict C++ compiler, as member functions in C++ get the additional definition of their class' *this as an invisible argument, which isn't compatible with the normal function pointer syntax.

[Scottapotamas]

https://stackoverflow.com/a/39176329 seems to cover the general issue reasonably well.

The easy way to resolve this seems to be passing in a data pointer, which is actually a pointer to the function (misdirection to trick the compiler).

The following snippet seems to compile fine:

void function_test()
{
  // do the thing
}

eui_cb_t user_callback = &function_test;

eui_message_t tracked_vars[] = 
{
  EUI_FUNC( "test", user_callback ),
};

• Test the implementation for AVR compiled programs
• Test Atmel ARM32
• Test ESP32 compatibility
• Test a 'pure' gcc C platform with STM32 or something
• See if it can be dressed in a macro?
• Documentation/example sketches