LPCSTR, TCHAR, String

Question

I am use next type of strings: LPCSTR, TCHAR, String i want to convert:

1. from TCHAR to LPCSTR
2. from String to char

I convert from TCHAR to LPCSTR by that code:

RunPath = TEXT("C:\\1");
LPCSTR Path = (LPCSTR)RunPath;

From String to char i convert by that code:

SaveFileDialog^ saveFileDialog1 = gcnew SaveFileDialog;
saveFileDialog1->Title = "Сохранение файла-настроек";
saveFileDialog1->Filter = "bck files (*.bck)|*.bck";
saveFileDialog1->RestoreDirectory = true;
pin_ptr<const wchar_t> wch = TEXT("");
if ( saveFileDialog1->ShowDialog() == System::Windows::Forms::DialogResult::OK ) {  
    wch = PtrToStringChars(saveFileDialog1->FileName);
} else return;
ofstream os(wch, ios::binary);

My problem is that when i set "Configuration Properties -> General Character Set in "Use Multi-Byte Character Set" the first part of code work correctly. But the second part of code return error C2440. When i set "Configuration Properties -> General Character Set in "Use Unicode" the second part of code work correctly. But the first part of code return the only first character from TCHAR to LPCSTR.

Answer 1

I'd suggest you need to be using Unicode the whole way through.

LPCSTR is a "Long Pointer to a C-type String". That's typically not what you want when you're dealing with .Net methods. The char type in .Net is 16bits wide.

You also should not use the TEXT("") macro unless you're planning multiple builds using various character encodings. Try wrapping all your string literals with the _W("") macro instead and a pure unicode build if you can.

See if that helps.

PS. std::wstring is very handy in your scenario.

EDIT

You see only one character because the string is now unicode but you cast it as a regular string. Many or most of the Unicode characters in the ASCII range has their same number as in ASCII but have the second of their 2 bytes set to zero. So when a unicode string is read as a C-string you only see the first character because C-strings are null ( zero ) terminated. The easy ( and wrong ) way to deal with this is to use std:wstring to cast as a std:string then pull the C-String out of that. This is not the safe approach because Unicode has a much large character space then your standard encoding.