ifdef Doxygen guard in SPI_Master - why???

[SlowTypist]

modm/src/modm/architecture/interface/spi_master.hpp

Line 33 in f01fd0a

#ifdef __DOXYGEN__

Why? What for? I am building a project, not a documentation. What for I need a doxygen here?

[salkinium]

Some of our interfaces are not "real", they are only there to document the signature of the implementation. However, some signatures are slightly different on different platforms, for example, on AVR we prefer to use smaller integers to pass arguments, since that reduces code size often quite significantly.

In modern times, you would perhaps use C++20 concepts to define them with a bunch of platform specific type aliases. But when we started these interfaces, we didn't have concepts yet.

[rleh]

In addition to the answer above: The actual (platform-dependent) implementations of the SPI master is located in modm/src/modm/platform/spi/*/, e.g.:

modm/src/modm/platform/spi/stm32/spi_master.hpp.in

Line 41 in f01fd0a

class SpiMaster{{ id }} : public modm::SpiMaster, public SpiLock<SpiMaster{{ id }}>