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Converting wostringstream to wchar_t* Garbles Values


Converting wostringstream to wchar_t* Garbles Values

By : user2955639
Date : November 22 2020, 10:40 AM
will help you The wostringstream::str() method returns a std::wstring by value. You are not assigning that to anything, so its lifetime is temporary and ends when the expression is finished. You are calling std::wstring::c_str() to save a pointer to the temporary's data, then the temporary gets destructed afterwards, leaving you with a stray pointer, thus causing undefined behavior in your subsequent code.
Instead of saving the std::wstring's data pointer, save the actual std::wstring object, and retrieve its data pointer only when actually needed.
code :


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Converting wchar_t* to char* on iOS

Converting wchar_t* to char* on iOS


By : DudeFromMars
Date : March 29 2020, 07:55 AM
This might help you Seems the issue was that the source string was encoded with a non-standard encoding (two ASCII characters for each wide character), which looked fine in the debugger, but clearly internally was sour. The error code produced is clearly not documented, but it's the equivalent to simply not being able to decode said piece of text.
Converting a UTF-8 text to wchar_t

Converting a UTF-8 text to wchar_t


By : Alozik
Date : March 29 2020, 07:55 AM
I hope this helps you . C does not define what encoding the char and wchar_t types are and the standard library only mandates some functions that translate between the two without saying how. If the implementation-dependent encoding of char is not UTF-8 then mbstowcs will result in data corruption.
As noted in the rationale for the C99 standard:
cannot convert argument 1 from 'ATL::CStringT<wchar_t,ATL::StrTraitATL<wchar_t,ATL::ChTraitsCRT<wchar_t>>

cannot convert argument 1 from 'ATL::CStringT<wchar_t,ATL::StrTraitATL<wchar_t,ATL::ChTraitsCRT<wchar_t>>


By : hector
Date : March 29 2020, 07:55 AM
help you fix your problem The variable 'csIndex' is a unicoce string(wchar_t), while the macro LPCSTR is for the ansi string (char).
So you should use Unicode functions, the code will be:
code :
lIndex = _wtoi((LPCWSTR)csIndex.Mid(3));
csIndex = (LPCSTR)(_bstr_t)vtIndex;
C++ Converting string to wchar_t

C++ Converting string to wchar_t


By : LiLei
Date : March 29 2020, 07:55 AM
it helps some times Re: your updated code;
There is a difference in lifetime between an automatic variable and a temporary.
code :
testing = "Two Two";
const wchar_t* buf = convert::stringToWideChar("leveljjj").c_str();
path.AddString(buf, wcslen(buf), &gFontFamily, FontStyleBold, 72, ptOrg, &strFormat);
testing = "Two Two";
std::wstring value = convert::stringToWideChar("leveljjj");
const wchar_t* buf = value.c_str();
path.AddString(buf, wcslen(buf), &gFontFamily, FontStyleBold, 72, ptOrg, &strFormat);
C++ Issue, Converting wchar_t* to string

C++ Issue, Converting wchar_t* to string


By : Lluvia Altan
Date : March 29 2020, 07:55 AM
help you fix your problem I am having a problem here. This is in Unicode. I have a stringtable that has values in it, separated by ;. I've been at this all day and I always end up with immediate runtime errors. , This statement:
code :
line = wcstok(readMap,L";");
line = wcstok(NULL,L";");
line = wcstok(readMap,L";"); // <-- reads the first line

while (line != NULL) {

    line = wcstok(NULL,L";"); // <-- 1st iteration throws away the first line
    wstring wstr(line); // <-- line will be NULL on last iteration

    //...
}
wchar_t* line = wcstok(readMap, L";");

while (line != NULL)
{
    // use line as needed...

    line = wcstok(NULL, L";");
}
for (wchar_t* line = wcstok(readMap, L";"); (line != NULL); line = wcstok(NULL, L";"))
{
    // use line as needed...
}
#include <string>
#include <sstream>

// after LoadString() exits, resid contains the
// number of character copied into readMap...
std::wistringstream iss(std::wstring(readMap, resid));

std::wstring line;
while (std::getline(iss, line, L';'))
{
    // use line as needed...
}
string str(wstr.begin(), wstr.end()); // Problem
std::wstring line;
while (std::getline(iss, line, L';'))
{
    std::string str;

    // optionally substitute CP_UTF8 with any ANSI codepage you want...
    int len = WideCharToMultiByte(CP_UTF8, 0, line.c_str(), line.length(), NULL, 0, NULL, NULL);
    if (len > 0)
    {
        str.resize(len);
        WideCharToMultiByte(CP_UTF8, 0, line.c_str(), line.length(), &str[0], len, NULL, NULL);
    }

    // use str as needed...
    MessageBoxW(0, line.c_str(), L"line", 0);
    MessageBoxA(0, str.c_str(), "str", 0);
}
#include <locale> 

std::wstring line;
while (std::getline(iss, line, L';'))
{
    std::wstring_convert<std::codecvt_utf8<wchar_t>, wchar_t> conv;
    std::string str = conv.to_bytes(line);

    // use str as needed...
    MessageBoxW(0, line.c_str(), L"line", 0);
    MessageBoxA(0, str.c_str(), "str", 0);
}
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