Turn off BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS for clang++

[hia3]

No description provided.

[jeking3]

We should probably switch to Boost.Predef here and detect dinkumware itself...

[hia3]

I have two variants:

1. Similar to this.

   #include <boost/predef.h>
   ...
   // I have no idea when Dinkumware added it, probably a lot
   // earlier than this check.
   #if defined(BOOST_LIB_STD_DINKUMWARE) && (BOOST_LIB_STD_DINKUMWARE >= BOOST_VERSION_NUMBER(6, 50, 0))

2. Or:

   #include <boost/predef.h>
   ...
   #if defined(BOOST_LIB_STD_DINKUMWARE) && (_MSVC_STL_VERSION >= 141)

Trying to summon @BillyONeal

[BillyONeal]

Hi there, my original PR didn't guard for compiler at all. I think this is a library property and _MSVC_STL_VERSION should be sufficient to identify but some maintainers were unhappy with that...

[BillyONeal]

We should probably switch to Boost.Predef here and detect dinkumware itself...

The difficulty here is that MSVC++'s standard library is a Dinkumware derivative but is no longer actually Dinkumware; so using a Dinkumware test to detect us will likely do the wrong thing on other Dinkumware licensees (e.g. I've heard rumors that Playstation still uses Dinkumware?).

[jeking3]

So _CPPLIB_VER identifies dinkumware, or a dinkumware derivitive, however we only want to set this BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS on MSVC if STL is version 140 or earlier, is that correct? And the change here is that MSVC started shipping with clang support built-in, so this change accounts for that case which was missing?

[BillyONeal]

BOOST_IOSTREAMS_HAS_DINKUMWARE_FPOS on MSVC if STL is version 140 or earlier, is that correct?

Right; other Dinkumware licensees likely still have the bigger-than-2-GiB file handling bugs we fixed.

[pdimov]

I see no reason to check the compiler macros here. _MSVC_STL_VERSION >= 141 should be enough.

edit: or rather, defined(_MSVC_STL_VERSION) && _MSVC_STL_VERSION >= 141 should be enough, to avoid a warning when _MSVC_STL_VERSION isn't defined.

[pdimov]

Original PR for reference: #57

[jeking3]

That's what I was thinking, but I wanted to clarify. Thanks @pdimov!

[jeking3]

Can we simplify this entire expression down to:

#if defined(_CPPLIB_VER) && (!defined(_MSVC_STL_VERSION) || _MSVC_STL_VERSION < 141)

perhaps?

[pdimov]

_YVALS is probably obsolete; I don't think we support pre-_CPPLIB_VER Dinkumware. Checking __SGI_STL_PORT or _STLPORT_VERSION seems redundant; I don't see how you can use both Dinkumware and STLport at the same time. Although who knows what happens on esoteric platforms. __QNX__ and __VXWORKS__ are probably checked because they use Dinkumware too? Not sure.

[pdimov]

#13 and #49 introduce the checks for VxWorks. Presumably QNX uses a similar Dinkumware version.

The STLPort checks come from 2d11830, without much of a history.

[pdimov]

Some more history: 3a18bc4, ccf8548

[codecov]

Codecov Report

Merging #77 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop      #77   +/-   ##
========================================
  Coverage    64.73%   64.73%           
========================================
  Files           81       81           
  Lines         3547     3547           
  Branches       950      950           
========================================
  Hits          2296     2296           
  Misses         461      461           
  Partials       790      790

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[jeking3]

Sadly we cannot test these platforms in our CI environment, so the safest thing to do is leave what's there and make the smallest modification possible.

[K-M-Ibrahim-Khalilullah]

@BillyONeal
I installed boost with pcl. Now how can I turn off for making it usable in my project