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Don't use __has_include() to test for C++11 headers

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This is unnecessary as we know that we have them in C++11 mode and we can't
compile them in non-C++11 mode even if they exist.

Not doing it simplifies the code and works around a bug in clang 3.2.

Closes https://github.com/wxWidgets/wxWidgets/pull/247
This commit is contained in:
Vadim Zeitlin
2016-03-07 02:09:07 +01:00
parent b0445661b1
commit c32fad09b8
1 changed files with 11 additions and 36 deletions
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47
include/wx/defs.h
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@@ -367,7 +367,8 @@ typedef short int WXTYPE;
/*
Check for C++11 compilers, it is important to do it before the
__has_include() checks because of g++ 4.9.2+ complications below.
__has_include() checks because at least g++ 4.9.2+ __has_include() returns
true for C++11 headers which can't be compiled in non-C++11 mode.
*/
#if __cplusplus >= 201103L || wxCHECK_VISUALC_VERSION(10)
#ifndef HAVE_TYPE_TRAITS
@@ -381,46 +382,20 @@ typedef short int WXTYPE;
#endif
#elif defined(__has_include)
/*
Notice that we trust our configure tests more than __has_include(),
notably the latter can return true even if the header exists but isn't
actually usable, as it happens with <type_traits> in non C++11 mode.
So if configure already detected at least one working alternative,
just use it.
We're in non-C++11 mode here, so only test for pre-C++11 headers. As
mentioned above, using __has_include() to test for C++11 would wrongly
detect them even though they can't be used in this case, don't do it.
*/
/*
Since 4.9.2, g++ provides __has_include() but, unlike clang, refuses to
compile the C++11 headers in C++98 mode (and we are sure we use the
latter because we explicitly checked for C++11 above).
*/
#if defined(__GNUC__) && !defined(__clang__)
#define wx_has_cpp11_include(h) 0
#else
#define wx_has_cpp11_include(h) __has_include(h)
#if !defined(HAVE_TR1_TYPE_TRAITS) && __has_include(<tr1/type_traits>)
#define HAVE_TR1_TYPE_TRAITS
#endif
#if !defined(HAVE_TYPE_TRAITS) && !defined(HAVE_TR1_TYPE_TRAITS)
#if wx_has_cpp11_include(<type_traits>)
#define HAVE_TYPE_TRAITS
#elif __has_include(<tr1/type_traits>)
#define HAVE_TR1_TYPE_TRAITS
#endif
#if !defined(HAVE_TR1_UNORDERED_MAP) && __has_include(<tr1/unordered_map>)
#define HAVE_TR1_UNORDERED_MAP
#endif
#if !defined(HAVE_STD_UNORDERED_MAP) && !defined(HAVE_TR1_UNORDERED_MAP)
#if wx_has_cpp11_include(<unordered_map>)
#define HAVE_STD_UNORDERED_MAP
#elif __has_include(<tr1/unordered_map>)
#define HAVE_TR1_UNORDERED_MAP
#endif
#endif
#if !defined(HAVE_STD_UNORDERED_SET) && !defined(HAVE_TR1_UNORDERED_SET)
#if wx_has_cpp11_include(<unordered_set>)
#define HAVE_STD_UNORDERED_SET
#elif __has_include(<tr1/unordered_set>)
#define HAVE_TR1_UNORDERED_SET
#endif
#if !defined(HAVE_TR1_UNORDERED_SET) && __has_include(<tr1/unordered_set>)
#define HAVE_TR1_UNORDERED_SET
#endif
#endif /* defined(__has_include) */