Possible to obtain netinet/in.h using gnulib-tool?

Question

I sort of ended up in the same problem as Getting started with gnulib on MinGW and not familiar (enough) with autotools - that is, wanting to include headers like netinet/in.h in a MinGW Windows project; and that is where I first heard of gnulib.

As the above post notes, the primary intention of gnulib is to sort of "patch" an existing autoconf project with the right files; however I work with a project whose build system I don't really understand - so at first, I thought of just copying headers.

Now, I'm not really sure, but it seems to me as if gnulib will generate these headers based on the system it is ran on - which is why instead of containing netinet/in.h verbatim, it in fact contains:

gnulib_git$ find . -name '*.h' | grep netinet
./lib/netinet_in.in.h

Indeed, this file has stuff like @PRAGMA_SYSTEM_HEADER@, which I can only assume are some macros.

So, I found there is a command --create-testdir, so I tried it like this:

rm -rf /tmp/AA # erase previous, else it won't run
./gnulib-tool --create-testdir --dir=/tmp/AA getsockname getsockopt setsockopt socket socketlib sockets socklen sys_socket arpa_inet inet_ntop inet_pton netinet_in
cd /tmp/AA
./configure
make

I've tried this on Linux, it runs fine, however:

$ find /tmp/AA -name '*.h' | grep netinet
/tmp/AA/gllib/netinet_in.in.h

... I still don't get any headers verbatim (and that one still has macros inside)? Turns out I cannot try this on my MinGW-w64, as there is no aclocal program there...

So could anyone explain whether full headers can ever be generated using --create-testdir, or how/when in the process can one expect to obtain the actual headers (and whether it is host OS dependent)?

Answer 1

gnulib will not create a netinet/in.h file of its own when it finds that the system's include file of the same name is fully functional - which is fortunately the case on glibc systems.

But on other platforms, like mingw, there likely will be a netinet/in.h file created by gnulib, and it will reference the system's include file of the same name. Yes, @PRAGMA_SYSTEM_HEADER@ is part of the macrology that makes this possible.

You don't need to have the Autotools on the target system (here: mingw). The idea of the GNU build system is that you create configure, Makefile.in, and config.h files on a machine with the Autotools. Then you can transport the resulting package to the target machine. On the target machine, per GNU standards, you only need the basic shell utilities (such as coreutils, sed, gawk).