error compiling on c-ares AIX

[amandeepgautam]

When trying to compile on AIX, I see the following error:

In file included from /tmp/aix_softwares/cares-1.14.0/ares_parse_a_reply.c:34:
/usr/include/arpa/nameser_compat.h:244:3: error: conflicting types for 'HEADER'
 } HEADER;
   ^~~~~~
In file included from /usr/include/arpa/nameser.h:645,
                 from /tmp/aix_softwares/cares-1.14.0/ares_parse_a_reply.c:29:
/usr/include/arpa/onameser_compat.h:265:3: note: previous declaration of 'HEADER' was here
 } HEADER;
   ^~~~~~

To compile, I did the following:

cd /path/to/cmake/source
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local/cares ..

Any suggestions on how to solve the problem? I would be willing to send a PR for this, if suggestion is given. Problem seems to be that on AIX both these HEADER is defined in both .h files. Please let me know.

[bradh352]

What version of AIX are you running? What version of c-ares are you testing (e.g. official 1.14.0 release, git master, etc)?

In my AIX version, at the top of nameser.h is a #define BIND_4_COMPAT which causes nameser_compat.h to be included if _USE_IRS is also defined. That said, I don't see anything setting _USE_IRS so onameser_compat.h would be included.

#ifdef _USE_IRS
#ifdef BIND_4_COMPAT
#include <arpa/nameser_compat.h>
#endif /* BIND_4_COMPAT */
#else /* _USE_IRS */
#include <arpa/onameser_compat.h>
#endif /* _USE_IRS */

So if things have changed on more recent versions of AIX we'd need to know how. Its possible it simply isn't appropriate to include arpa/nameser_compat.h manually any longer on AIX. Either that or previously we really should have just done
#define _USE_IRS
rather than manually including nameser_compat.h.

[amandeepgautam]

I am using AIX 7200-01-03-1720 and official release 1.14.0 release.
Following is how the two files look on this versions of AIX:
https://pastebin.com/c9VZPwGn
https://pastebin.com/WcjMnffk

[bradh352]

basically looks the same, not sure why I'm not seeing that same issue on AIX 5. I really think the solution is to set _USE_IRS on AIX. I wonder if autotools doesn't already set that flag and its just something we ned to add to cmake.

[amandeepgautam]

@bradh352 I am very unfamiliar with the code base but if you could explain in more detail, i could give it a try and test it.

[bradh352]

If you try the current git master, I've made the change for the CMakeLists.txt to define _USE_IRS on AIX.

[amandeepgautam]

@bradh352 yes that compiles. Thanks for fixing this.
However, it only generates 32-bit lib? How could we generate 64-bit libs?

[bradh352]

That's just whatever your compiler and tools default to. No build system ever builds both 32bit and 64bit.

From what I recall though, on AIX, pretty much everything honors the OBJECT_MODE environment variable and the valid values are/were 32 or 64.