src/*/Submakefile: Why do we copy header files to a common include directory?

[smoe]

Hello in src/emc/Submakefile and its siblings, we are copying header files from the subdirectories to a common include directory:

INCLUDES += emc

$(patsubst ./emc/%,../include/%,$(wildcard ./emc/*.h)): ../include/%.h: ./emc/%.h
        cp $^ $@

$(patsubst ./emc/%,../include/%,$(wildcard ./emc/*.hh)): ../include/%.hh: ./emc/%.hh
        cp $^ $@

I have not fully grasped why we are doing this. These files are truly copied, not symlinked. And I am not an ultimate fan seeing all the many header files from different parts of the source tree coming together into a single namespace.

[andypugh]

It looks like @petterreinholdtsen did it in 2021.

Values not detected at compile time, ie LINELEN, BUFFERLEN, MM_PER_INCH
and INCH_PER_MM, are moved into a new file linuxchc.h.

To avoid having to install the architecture specific config.h file,
restructure includes and introduce linuxcnc.h for definitions used
across the code.  Drop the redundant MM_PER_INCH from
interp_internal.hh and CMS_CONFIG_LINELEN from cms_cfg.hh and use the
value from linuxcnc.h instead.  Made sure all C files depending on
config.h values include it directly.  Make sure no header file include
config.h.

As uspace_common.h is not exposed to API clients, and is a code
fragment and not a normal include file, the use of config.h is left
as it is there.

Which doesn't answer the question for me, but maybe does for you?

[rmu75]

Those include files go into the -dev .deb file and should be sufficient to build external stuff interfacing with linuxcnc without requiring full source.