[英]how to convert const WCHAR * to const char *
CString output ;
const WCHAR* wc = L"Hellow World" ;
if( wc != NULL )
{
output.Append(wc);
}
printf( "output: %s\n",output.GetBuffer(0) );
你也可以試試這個:
#include <comdef.h> // you will need this
const WCHAR* wc = L"Hello World" ;
_bstr_t b(wc);
const char* c = b;
printf("Output: %s\n", c);
_bstr_t
實現了以下轉換操作符,我覺得這很方便:
operator const wchar_t*( ) const throw( );
operator wchar_t*( ) const throw( );
operator const char*( ) const;
operator char*( ) const;
編輯:關於回答評論的澄清: line const char* c = b;
導致字符串的窄字符副本由_bstr_t
實例創建和管理,該實例將在銷毀時釋放一次。 運算符只返回一個指向該副本的指針。 因此,無需復制此字符串。 此外,在問題中, CString::GetBuffer
返回LPTSTR
(即TCHAR*
)而不是LPCTSTR
(即const TCHAR*
)。
另一種選擇是使用轉換宏:
USES_CONVERSION;
const WCHAR* wc = L"Hello World" ;
const char* c = W2A(wc);
這種方法的問題是轉換后的字符串的內存是在棧上分配的,所以字符串的長度是有限的。 但是,這一系列轉換宏允許您選擇用於轉換的代碼頁,如果寬字符串包含非 ANSI 字符,則通常需要這樣做。
為此,您可以使用sprintf
:
const char output[256];
const WCHAR* wc = L"Hellow World" ;
sprintf(output, "%ws", wc );
我的 Linux 代碼
// Debian GNU/Linux 8 "Jessie" (amd64)
#include <locale.h>
#include <stdlib.h>
#include <stdio.h>
// Use wcstombs(3) to convert Unicode-string (wchar_t *) to UTF-8 (char *)
// http://man7.org/linux/man-pages/man3/wcstombs.3.html
int f(const wchar_t *wcs) {
setlocale(LC_ALL,"ru_RU.UTF-8");
printf("Sizeof wchar_t: %d\n", sizeof(wchar_t));
// on Windows, UTF-16 is internal Unicode encoding (UCS2 before WinXP)
// on Linux, UCS4 is internal Unicode encoding
for (int i = 0; wcs[i] > 0; i++) printf("%2d %08X\n",i,wcs[i]);
char s[256];
size_t len = wcstombs(s,wcs,sizeof(s));
if (len > 0) {
s[len] = '\0';
printf("mbs: %s\n",s);
for (int i = 0; i < len; i++)
printf("%2d %02X\n",i,(unsigned char)s[i]);
printf("Size of mbs, in bytes: %d\n",len);
return 0;
}
else return -1;
}
int main() {
f(L"Привет"); // 6 symbols
return 0;
}
如何構建
#!/bin/sh
NAME=`basename $0 .sh`
CC=/usr/bin/g++-4.9
INCS="-I."
LIBS="-L."
$CC ${NAME}.c -o _${NAME} $INCS $LIBS
輸出
$ ./_test
Sizeof wchar_t: 4
0 0000041F
1 00000440
2 00000438
3 00000432
4 00000435
5 00000442
mbs: Привет
0 D0
1 9F
2 D1
3 80
4 D0
5 B8
6 D0
7 B2
8 D0
9 B5
10 D1
11 82
Size of mbs, in bytes: 12
你可以這樣做,或者你可以做一些更清潔的事情:
std::wcout << L"output: " << output.GetString() << std::endl;
這很容易,因為CString
只是CStringT
,並且您還可以訪問CStringA
和CStringW
(您應該閱讀有關差異的文檔)。
CStringW myString = L"Hello World";
CString myConvertedString = myString;
您可以為此目的使用sprintf
,正如@l0pan 所提到的(但我使用了%ls
而不是%ws
):
char output[256];
const WCHAR* wc = L"Hello World" ;
sprintf(output, "%ws", wc ); // did not work for me (Windows, C++ Builder)
sprintf(output, "%ls", wc ); // works
您可以使用std::wcsrtombs
函數。
這是用於轉換的C++17重載集:
#include <iostream> // not required for the conversion function
// required for conversion
#include <cuchar>
#include <cwchar>
#include <stdexcept>
#include <string>
#include <string_view> // for std::wstring_view overload
std::string to_string(wchar_t const* wcstr){
auto s = std::mbstate_t();
auto const target_char_count = std::wcsrtombs(nullptr, &wcstr, 0, &s);
if(target_char_count == static_cast<std::size_t>(-1)){
throw std::logic_error("Illegal byte sequence");
}
// +1 because std::string adds a null terminator which isn't part of size
auto str = std::string(target_char_count, '\0');
std::wcsrtombs(str.data(), &wcstr, str.size() + 1, &s);
return str;
}
std::string to_string(std::wstring const& wstr){
return to_string(wstr.c_str());
}
std::string to_string(std::wstring_view const& view){
// wstring because wstring_view is not required to be null-terminated!
return to_string(std::wstring(view));
}
int main(){
using namespace std::literals;
std::cout
<< to_string(L"wchar_t const*") << "\n"
<< to_string(L"std::wstring"s) << "\n"
<< to_string(L"std::wstring_view"sv) << "\n";
}
如果你使用 Pre-C++17,你應該緊急更新你的編譯器! ;-)
如果這真的不可能,這里有一個 C++11 版本:
#include <iostream> // not required for the conversion function
// required for conversion
#include <cwchar>
#include <stdexcept>
#include <string>
std::string to_string(wchar_t const* wcstr){
auto s = std::mbstate_t();
auto const target_char_count = std::wcsrtombs(nullptr, &wcstr, 0, &s);
if(target_char_count == static_cast<std::size_t>(-1)){
throw std::logic_error("Illegal byte sequence");
}
// +1 because std::string adds a null terminator which isn't part of size
auto str = std::string(target_char_count, '\0');
std::wcsrtombs(const_cast<char*>(str.data()), &wcstr, str.size() + 1, &s);
return str;
}
std::string to_string(std::wstring const& wstr){
return to_string(wstr.c_str());
}
int main(){
std::cout
<< to_string(L"wchar_t const*") << "\n"
<< to_string(std::wstring(L"std::wstring")) << "\n";
}
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