Include statements included in target header files

[matanox]

This is a usage / feature question which I hope is trivial to answer. When the header file which we unleash the tool on contains #include statements itself, is it currently supported to seamlessly generate also for those referenced header files?

For example:

Header file XKBlib.h (/usr/include/X11/XKBlib.h) will typically contain the following includes:

#include <X11/Xlib.h>
#include <X11/extensions/XKBstr.h>

Unless I'm experiencing a very specific bug, by plainly running the tool on this header file, I think that these referenced header files will not be processed.

Rather I will need to manually follow the chain of includes contained within the header file, and invoke this tool on each of them, in order to get all the symbols of the library of interest ready for ctypes use in python (I mean the library of which XKBlib.h is the "core" include file for, if this kind of naive relationship typically makes sense). Put differently, unlike the C compiler/s, this tool will not seamlessly follow referenced headers.

I am happy to learn whether this is a feature request or already implemented.

Or maybe it's uncommon for libraries to require the upstream user code to directly use symbols from nested header files and hence doesn't make sense (?!).

Thanks!

[matanox]

I'm seeing the -I option, but I think it's not exactly the same or just doesn't help getting the referenced header files processed, in my case.

[Alan-R]

Not certain if this is behaving the way you stated or not. I'm fairly certain that I have code which works the way you want it to work, not the way you describe it as behaving.
Can you give a specific example (ideally on Linux) with the specific options (like -I) you included with the output you got, along with the output you expected.

The default system header files occur in wildly different places on different platforms and compilers - and they change over time. It is necessary to include -I directories for all the places you expect headers to be parsed.

[mara004]

To the OP: yes, all include statements should be expanded by the C preprocessor called by ctypesgen, but you will have to either pass the indirect headers to ctypesgen directly OR use --all-headers OR explicit include rules, AND add all libraries plus their directories to the ctypesgen cmd to expose e.g. X11 API functions.
If you don't, only direct dependencies like structs and typedefs get pulled into the output.

This branch of ctypesgen has that multilib support, but internally it's a bit of a messy matter IMHO.
Often it may be cleaner to create an independent binding to e.g. X11 first, and then use -m / --link-modules to use symbols from that binding.

Ctypesgen cannot traverse the dependency tree and create separate linked bindings to different libs automatically.
Similar to how C compilers can't automatically build dependency libraries.

See also #86 (comment) and pypdfium2-team#1 for considerations.