std::wbuffer_convert<Codecvt,Elem,Tr>::wbuffer_convert
From cppreference.com
< cpp | locale | wbuffer convert
| wbuffer_convert() : wbuffer_convert(nullptr) {} |
(1) | |
| explicit wbuffer_convert( std::streambuf* bytebuf, Codecvt* pcvt = new Codecvt, |
(2) | |
| wbuffer_convert( const std::wbuffer_convert& ) = delete; |
(3) | (since C++14) |
| Overload | Data members | ||
|---|---|---|---|
bufptr
|
cvtptr
|
cvtstate
| |
| (1) | nullptr | new Codecvt | state_type() |
| (2) | bytebuf | pcvt | state |
2) If pcvt is a null pointer, the behavior is undefined.
Parameters
| bytebuf | - | pointer to the underlying buffer |
| pcvt | - | pointer to a standalone (not managed by a locale) facet |
| state | - | the initial value of the character conversion state |
Example
Run this code
#include <codecvt> #include <iostream> #include <locale> #include <sstream> int main() { // Wrap a UTF-8 string stream in a UCS4 wbuffer_convert std::stringbuf utf8buf("z\u00df\u6c34\U0001f34c"); // or "\x7a\xc3\x9f\xe6\xb0\xb4\xf0\x9f\x8d\x8c" // or u8"zß水🍌" std::wbuffer_convert<std::codecvt_utf8<wchar_t>> conv_in(&utf8buf); std::wistream ucsbuf(&conv_in); std::cout << "Reading from a UTF-8 stringbuf via wbuffer_convert: " << std::hex << std::showbase; for (wchar_t c; ucsbuf.get(c);) std::cout << static_cast<std::wint_t>(c) << ' '; // Wrap a UTF-8 aware std::cout in a UCS4 wbuffer_convert to output UCS4 std::wbuffer_convert<std::codecvt_utf8<wchar_t>> conv_out(std::cout.rdbuf()); std::wostream out(&conv_out); std::cout << "\nSending UCS4 data to std::cout via wbuffer_convert: "; out << L"z\u00df\u6c34\U0001f34c\n"; }
Output:
Reading from a UTF-8 stringbuf via wbuffer_convert: 0x7a 0xdf 0x6c34 0x1f34c Sending UCS4 data to std::cout via wbuffer_convert: zß水🍌
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 |