std::codecvt::encoding, std::codecvt::do_encoding
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<tbody> </tbody> public: int encoding() const |
(1) | |
protected: int do_encoding() const |
(2) | |
1)
-,
do_encoding - .:
public member function, calls the member function
do_encoding of the most derived class.2) if the encoding represented by this codecvt facet maps each internal character to the same, constant number of external characters, returns that number. If the encoding is variable-length (e.g. UTF-8 or UTF-16), returns 0. If the encoding is state-dependent, returns -1.
The exact number of externT characters that correspond to one internT character, if constant. 0 if the number varies, -1 if the encoding is state-dependent.
std::codecvt<char, char, std::mbstate_t> 1 noexcept:
noexcept#include <locale>
#include <iostream>
int main()
{
std::cout << "en_US.utf8 is a variable-length encoding, encoding() returns "
<< std::use_facet<std::codecvt<wchar_t, char, std::mbstate_t>>(
std::locale("en_US.utf8")
).encoding() << '\n';
std::cout << "zh_CN.gb18030 is also variable-length, encoding() == "
<< std::use_facet<std::codecvt<wchar_t, char, std::mbstate_t>>(
std::locale("zh_CN.gb18030")
).encoding() << '\n';
std::cout << "ru_RU.koi8r is a single-byte encoding encoding() == "
<< std::use_facet<std::codecvt<wchar_t, char, std::mbstate_t>>(
std::locale("ru_RU.koi8r")
).encoding() << '\n';
}
:
en_US.utf8 is a variable-length encoding, encoding() returns 0
zh_CN.gb18030 is also variable-length, encoding() == 0
ru_RU.koi8r is a single-byte encoding encoding() == 1
.
MB_CUR_MAX |
C () |
[virtual] |
externT , internT : returns the maximum number of externT characters that could be converted into a single internT character (virtual protected -) |