[BuildTools] Question regarding header and type detection in CoinUtils

[Stefan Vigerske]

Hi,

defining and exporting COINUTILS_HAS_CINTTYPES and 
COINUTILS_HAS_INTTYPES_H and thus including the (c)inttypes(.h) header 
in CoinTypes.h sounds best to me.
It's a bit complicated, as we already have HAVE_CINTTYPES and 
HAVE_INTTYPES_H, but it seems to be clean and safe.

While doing so, you could then also introduce COINUTILS_HAS_CSTDINT :-).
COINUTILS_HAS_STDINT_H was indeed added a year ago to fix some specific 
issues.

Stefan


On 10/03/2014 04:47 PM, Ted Ralphs wrote:
> Hi everyone,
>
> This e-mail is probably directed mostly at Stefan, but if anyone else has
> an opinion, feel free to weigh in.
>
> I'm trying to build CoinAll with Visual Studio 9 (we still need to support
> it because of Python extensions) on a new laptop running Windows 8 that
> also has Visual Studio 12 installed (yes, I know I'm asking for trouble).
> For reasons I cannot discern, the compiler is using a combination of the
> headers from both compiler versions (9 and 12), which may or may not be
> related to the issues I'm seeing. In a nutshell, code that builds fine on
> my old laptop now fails to build with the exact same compiler.This has
> caused me to dig into some stuff that I found does not completely make
> sense to me.
>
> The problem arises from the check for the type int64_t in the configure
> script for CoinUtils, which is done as so.
>
> AC_CHECK_TYPE([int64_t],[CoinInt64=int64_t ; CoinUInt64=uint64_t],[],[
> #ifdef HAVE_CINTTYPES
> # include <cinttypes>
> #else
> # ifdef HAVE_INTTYPES_H
> #  include <inttypes.h>
> # endif
> #endif
> ])
>
> The type int64_t is found at configure time (I think in the header
> cintypes), but only because the inttypes headers have been manually
> included for the test. In CoinTypes.hpp, these headers are *not* currently
> included and thus, the type is not found at compile time, which leads to an
> error.
>
> Adding the same block of code from the test above to CoinTypes.hpp fixes
> the problem for CoinUtils, but building Cbc then fails because the symbols
> HAVE_CINTTYPES and HAVE_INTTYPES_H are not exported to config_coinutils.h.
> If I export the symbols
>
> COINUTILS_HAS_CINTTYPES
> COINUTILS_HAS_INTTYPES_H
>
> then everything is fine. I have no idea why this was working fine in the
> recent past and now it suddenly causes a problem or why everything is fine
> on Linux and OS X. I suppose that type must be found in a different header
> on those OS's.
>
> Now my questions:
>
> 1. Another solution would be to check for the type int64_t without
> including the headers manually, which would then not require including them
> in CoinTypes.hpp. We would then just use long long instead of int64_t I
> suppose. I don't think this is the right solution, but I wanted to see if
> anyone had a different opinion.
>
> 2. This all made me realize that we have a block like this in CoinTypes.hpp.
>
> #ifdef COINUTILS_HAS_STDINT_H
> #include <stdint.h>
> #endif
>
> Why do we only check for stdint.h and not cstdint (as we do with inttypes).
> With the Visual Studio build, it is finding cstdint, not stdint.h, but then
> not including it. Of course, this is not causing a problem at the moment,
> but should we also export COINUTILS_HAS_CSTDINT? I haven't checked for
> blame, but I'm sure that code was inserted in there to solve some specific
> issue with finding types on some platform, but I guess that it would be
> more portable and correct if cstdint were also included when it's
> available.
>
> If you read this far, let me know what you think and sorry for the long and
> detailed mail!
>
> Cheers,
>
> Ted
>
>
>
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