std::wbuffer_convert<Codecvt,Elem,Tr>::wbuffer_convert
From cppreference.com
wbuffer_convert() : wbuffer_convert(nullptr) {} |
(1) | |
explicit wbuffer_convert( std::streambuf* bytebuf, Codecvt* pcvt = new Codecvt, state_type state = state_type() ); |
(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 |