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Defined in header <filesystem> | ||
template<class Source> std::filesystem::path u8path(const Source& source); | (1) | (since C++17) (deprecated in C++20) |
template<class InputIt> std::filesystem::path u8path( InputIt first, InputIt last); | (2) | (since C++17) (deprecated in C++20) |
Constructs a pathp from a UTF-8 encoded sequence ofchars orchar8_ts(since C++20), supplied either as anstd::string, or asstd::string_view, or as a null-terminated multibyte string, or as a[first, last) iterator pair.
path::value_type ischar and native encoding is UTF-8, constructs a path directly as if bypath(source) orpath(first, last). Note: this is the typical situation of a POSIX system that uses Unicode, such as Linux.path::value_type iswchar_t and native encoding is UTF-16 (this is the situation on Windows), or ifpath::value_type ischar16_t (native encoding guaranteed UTF-16) orchar32_t (native encoding guaranteed UTF-32), then first converts the UTF-8 character sequence to a temporary stringtmp of typepath::string_type and then the new path is constructed as if bypath(tmp).tmp of typestd::u32string, and then the new path is constructed as if bypath(tmp) (this path is taken on a POSIX system with a non-Unicode multibyte or single-byte encoded filesystem).Contents |
| source | - | a UTF-8 encodedstd::string,std::string_view, a pointer to a null-terminated multibyte string, or an input iterator with char value type that points to a null-terminated multibyte string |
| first, last | - | pair ofLegacyInputIterators that specify a UTF-8 encoded character sequence |
| Type requirements | ||
-InputIt must meet the requirements ofLegacyInputIterator. | ||
-The value type ofSource orInputIt must becharorchar8_t.(since C++20) | ||
The path constructed from the input string after conversion from UTF-8 to the filesystem's native character encoding.
May throwstd::bad_alloc if memory allocation fails.
On systems where native path format differs from the generic path format (neither Windows nor POSIX systems are examples of such OSes), if the argument to this function is using generic format, it will be converted to native.
#include <cstdio>#ifdef _MSC_VER#include <fcntl.h>#include <io.h>#else#include <clocale>#include <locale>#endif#include <filesystem>#include <fstream> int main(){#ifdef _MSC_VER _setmode(_fileno(stderr), _O_WTEXT);#elsestd::setlocale(LC_ALL,"");std::locale::global(std::locale(""));#endif std::filesystem::path p(u8"要らない.txt");std::ofstream(p)<<"File contents";// Prior to LWG2676 uses operator string_type()// on MSVC, where string_type is wstring, only// works due to non-standard extension.// Post-LWG2676 uses new fstream constructors // Native string representation can be used with OS-specific APIs#ifdef _MSC_VERif(std::FILE* f= _wfopen(p.c_str(), L"r"))#elseif(std::FILE* f=std::fopen(p.c_str(),"r"))#endif{for(int ch;(ch= fgetc(f))!=EOF;std::putchar(ch)){}std::fclose(f);} std::filesystem::remove(p);}
Possible output:
File contents
(C++17) | represents a path (class)[edit] |
