| Localization library | |||||||||||||||||||||||||
| Regular expressions library(C++11) | |||||||||||||||||||||||||
| Formatting library(C++20) | |||||||||||||||||||||||||
| Null-terminated sequence utilities | |||||||||||||||||||||||||
| Byte strings | |||||||||||||||||||||||||
| Multibyte strings | |||||||||||||||||||||||||
| Wide strings | |||||||||||||||||||||||||
| Primitive numeric conversions | |||||||||||||||||||||||||
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| Text encoding identifications | |||||||||||||||||||||||||
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| Functions | ||||||||||||||||||||||||||
| Character classification | ||||||||||||||||||||||||||
| Character manipulation | ||||||||||||||||||||||||||
| Conversions to numeric formats | ||||||||||||||||||||||||||
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| String manipulation | ||||||||||||||||||||||||||
| String examination | ||||||||||||||||||||||||||
| Array manipulation | ||||||||||||||||||||||||||
Defined in header <cwchar> | ||
std::size_t wcsxfrm(wchar_t* dest,constwchar_t* src,std::size_t count); | ||
Transforms the null-terminated wide string pointed to bysrc into the implementation-defined form such that comparing two transformed strings withstd::wcscmp gives the same result as comparing the original strings withstd::wcscoll, in the current C locale.
The firstcount characters of the transformed string are written to destination, including the terminating null character, and the length of the full transformed string is returned, excluding the terminating null character.
Ifcount is0, thendest is allowed to be a null pointer.
Contents |
The correct length of the buffer that can receive the entire transformed string is1+ std::wcsxfrm(nullptr, src,0).
This function is used when making multiple locale-dependent comparisons using the same wide string or set of wide strings, because it is more efficient to usestd::wcsxfrm to transform all the strings just once, and subsequently compare the transformed wide strings withstd::wcscmp.
| dest | - | pointer to the first element of a wide null-terminated string to write the transformed string to |
| src | - | pointer to the null-terminated wide character string to transform |
| count | - | maximum number of characters to output |
The length of the transformed wide string, not including the terminating null-character.
#include <cwchar>#include <iostream> int main(){std::setlocale(LC_ALL,"sv_SE.utf8"); std::wstring in1= L"\u00e5r";std::wstring out1(1+ std::wcsxfrm(nullptr, in1.c_str(),0), L' ');std::wstring in2= L"\u00e4ngel";std::wstring out2(1+ std::wcsxfrm(nullptr, in2.c_str(),0), L' '); std::wcsxfrm(&out1[0], in1.c_str(), out1.size()); std::wcsxfrm(&out2[0], in2.c_str(), out2.size()); std::wcout<<"In the Swedish locale: ";if(out1< out2)std::wcout<< in1<<" before "<< in2<<'\n';elsestd::wcout<< in2<<" before "<< in1<<'\n'; std::wcout<<"In lexicographical comparison: ";if(in1< in2)std::wcout<< in1<<" before "<< in2<<'\n';elsestd::wcout<< in2<<" before "<< in1<<'\n'; }
Output:
In the Swedish locale: år before ängelIn lexicographical comparison: ängel before år
transform a string so thatstrcmp would produce the same result asstrcoll(function)[edit] | |
[virtual] | transforms a string so that collation can be replaced by comparison (virtual protected member function of std::collate<CharT>)[edit] |
| compares two wide strings in accordance to the current locale (function)[edit] | |
C documentation forwcsxfrm | |
