std::wstring_convert<Codecvt,Elem,Wide_alloc,Byte_alloc>::wstring_convert
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< cpp | locale | wstring convert
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String and stream conversions Unicode conversion facets C library locales
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std::wstring_convert
Member functions
wstring_convert::wstring_convert
wstring_convert() : wstring_convert( new Codecvt ) {}
(1)
explicit wstring_convert( Codecvt* pcvt );
(2)
wstring_convert( Codecvt* pcvt, state_type state );
(3)
explicit wstring_convert( const byte_string& byte_err,
const wide_string& wide_err = wide_string() );
(4)
const wide_string& wide_err = wide_string() );
wstring_convert( const std::wstring_convert & ) = delete;
(5)
(since C++14)
| Overload | Data members | ||||
|---|---|---|---|---|---|
byte_err_string
|
wide_err_string
|
cvtptr
|
cvtstate
|
cvtcount
| |
| (1) | default-initialized | new Codecvt | default-initialized | uninitialized | |
| (2) | pcvt | ||||
| (3) | state | ||||
| (4) | byte_err | wide_err | new Codecvt | state_type() | |
2,3) If pcvt is a null pointer, the behavior is undefined.
[edit] Parameters
pcvt
-
pointer to the conversion facet
state
-
initial value of the conversion shift state
byte_err
-
narrow string to display on errors
wide_err
-
wide string to display on errors
[edit] Example
Run this code
#include <codecvt> #include <locale> #include <utility> // utility wrapper to adapt locale-bound facets for wstring/wbuffer convert template<class Facet> struct deletable_facet : Facet { using Facet::Facet; // inherit constructors ~deletable_facet() {} }; int main() { // UTF-16le / UCS4 conversion std::wstring_convert <std::codecvt_utf16 <char32_t, 0x10ffff, std::little_endian >> u16to32; // UTF-8 / wide string conversion with custom messages std::wstring_convert <std::codecvt_utf8 <wchar_t>> u8towide("Error!", L"Error!"); // GB18030 / wide string conversion facet using F = deletable_facet<std::codecvt_byname <wchar_t, char, std::mbstate_t >>; std::wstring_convert <F> gbtowide(new F("zh_CN.gb18030")); }
[edit] Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior |
|---|---|---|---|
| LWG 2175 | C++11 | pcvt could be a null pointer | the behavior is undefined in this case |
| LWG 2176 | C++11 | constructors accepting single argument were implicit | made explicit |
| P0935R0 | C++11 | the default constructor was explicit | made implicit |