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| author | Jonathan Wakely <jwakely@redhat.com> | 2020-11-01 10:56:36 +0000 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2020-11-01 11:39:07 +0000 |
| commit | 29e418485848c4a6943d8561cd8fb0b1abf14015 (patch) | |
| tree | a407e74705910515e38c711a08313bfb0b3d5551 | |
| parent | de77abee118f1900fceb25c34b0cc1ef7261c9ce (diff) | |
| download | gcc-29e418485848c4a6943d8561cd8fb0b1abf14015.zip gcc-29e418485848c4a6943d8561cd8fb0b1abf14015.tar.gz gcc-29e418485848c4a6943d8561cd8fb0b1abf14015.tar.bz2 | |
libstdc++: Define type traits for wchar_t even when libc support missing
This meets the requirement that std::is_integral_v<wchar_t> is true,
even when full library support for wchar_t via specializations of
char_traits etc. is not provided. This is done by checking
__WCHAR_TYPE__ to see if the compiler knows about the type, rather than
checking the library's own _GLIBCXX_USE_WCHAR_T autoconf macro.
This assumes that the C++ compiler correctly defines wchar_t as a
distinct type, not a typedef for one of the other integeral types. This
is always true for G++ and should be true for any supported non-GNU
compilers.
Similarly, the std::make_unsigned and std::make_signed traits and the
internal helpers std::__is_integer and std::__is_char are also changed
to depend on the same macro.
libstdc++-v3/ChangeLog:
* include/std/type_traits (is_integral<wchar_t>)
(make_unsigned<wchar_t>, make_signed<wchar_t>): Define based
on #ifdef __WCHAR_TYPE__ instead of _GLIBCXX_USE_WCHAR_T.
* include/bits/cpp_type_traits.h (__is_integer<wchar_t>)
(__is_char<wchar_t>): Likewise.
| -rw-r--r-- | libstdc++-v3/include/bits/cpp_type_traits.h | 4 | ||||
| -rw-r--r-- | libstdc++-v3/include/std/type_traits | 9 |
2 files changed, 8 insertions, 5 deletions
diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h b/libstdc++-v3/include/bits/cpp_type_traits.h index b48d1ad..433a2d7 100644 --- a/libstdc++-v3/include/bits/cpp_type_traits.h +++ b/libstdc++-v3/include/bits/cpp_type_traits.h @@ -162,7 +162,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION typedef __true_type __type; }; -# ifdef _GLIBCXX_USE_WCHAR_T +# ifdef __WCHAR_TYPE__ template<> struct __is_integer<wchar_t> { @@ -363,7 +363,7 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3) typedef __true_type __type; }; -#ifdef _GLIBCXX_USE_WCHAR_T +#ifdef __WCHAR_TYPE__ template<> struct __is_char<wchar_t> { diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits index e9a0f55..34e068b 100644 --- a/libstdc++-v3/include/std/type_traits +++ b/libstdc++-v3/include/std/type_traits @@ -269,7 +269,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION struct __is_integral_helper<unsigned char> : public true_type { }; -#ifdef _GLIBCXX_USE_WCHAR_T + // We want is_integral<wchar_t> to be true (and make_signed/unsigned to work) + // even when libc doesn't provide working <wchar.h> and related functions, + // so check __WCHAR_TYPE__ instead of _GLIBCXX_USE_WCHAR_T. +#ifdef __WCHAR_TYPE__ template<> struct __is_integral_helper<wchar_t> : public true_type { }; @@ -1742,7 +1745,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // neither signed integer types nor unsigned integer types, so must be // transformed to the unsigned integer type with the smallest rank. // Use the partial specialization for enumeration types to do that. -#if defined(_GLIBCXX_USE_WCHAR_T) +#ifdef __WCHAR_TYPE__ template<> struct __make_unsigned<wchar_t> { @@ -1868,7 +1871,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // signed integer types nor unsigned integer types, so must be // transformed to the signed integer type with the smallest rank. // Use the partial specialization for enumeration types to do that. -#if defined(_GLIBCXX_USE_WCHAR_T) +#if defined(__WCHAR_TYPE__) template<> struct __make_signed<wchar_t> { |