How to convert string to LPWSTR in c++

Question

Can anyone help in converting string to LPWSTR

string command=obj.getInstallationPath()+"<some string appended>"  

Now i wat to pass it as parameter for CreateProcessW(xx,command,x...)

But createProcessW() accepts only LPWSTR so i need to cast string to LPWSTR

Thanks in Advance

Answer 1

If you have an ANSI string, then have you considered calling CreateProcessA instead? If there is a specific reason you need to call CreateProcessW then you will need to convert the string. Try the MultiByteToWideChar function.

Answer 2

Another way:

mbstowcs_s

use with string.c_str(), you can find example here or here

OR

USES_CONVERSION_EX;

std::string text = "text";
LPWSTR lp = A2W_EX(text.c_str(), text.length());

OR

{
    std::string str = "String to LPWSTR";
    BSTR b = _com_util::ConvertStringToBSTR(str.c_str());
    LPWSTR lp = b;
    Use lp before SysFreeString...
    SysFreeString(b);
}

Answer 3

The easiest way to convert an ansi string to a wide (unicode) string is to use the string conversion macros .

To use these, put USES_CONVERSION at the top of your function, then you can use macros like A2W() to perform the conversion very easily.

eg.

char* sz = "tadaaa";
CreateProcessW(A2W(sz), ...);

The macros allocate space on the stack, perform the conversion and return the converted string.

Answer 4

Also, you might want to consider using TCHAR throughout... If I'm correct, the idea would be something like this:

typedef std::basic_string<TCHAR> tstring

// Make any methods you control return tstring values. Thus, you could write:
tstring command = obj.getInstallationPath();
CreateProcess(x, command.c_str(), ...);

Note that we use CreateProcess instead of CreateProcessW or CreateProcessA . The idea is that if UNICODE is defined, then TCHAR is typedef ed to WCHAR and CreateProcess is #define d to be CreateProcessW , which accepts a LPWSTR ; but if UNICODE is not defined, then TCHAR becomes char , and CreateProcess becomes CreateProcessA , which accepts a LPSTR . But I might not have the details right here... this stuff seems somewhat needlessly complicated :(.

Answer 5

You could store it in a CString and call the LPWSTR operator on it:

const char* sz = "tadaaa";
const CString s( sz );
LPCWSTR ws = static_cast<LPCWSTR>( s ); //calling CString::operator (LPCWSTR)()const;

Note that the WSTR cast operator is only defined for unicode builds.

Answer 6

Here is another option. I've been using this function to do the conversion.

//C++ string to WINDOWS UNICODE string
std::wstring s2ws(const std::string& s)
{
   int len;
   int slength = (int)s.length() + 1;
   len = MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, 0, 0); 
   wchar_t* buf = new wchar_t[len];
   MultiByteToWideChar(CP_ACP, 0, s.c_str(), slength, buf, len);
   std::wstring r(buf);
   delete[] buf;
   return r;
}

And wrap your string like this. s2ws( volume.c_str())

Answer 7

#include "vcclr.h" //for PtrToStringChars

// Convert function
LPWSTR S2W(String^ string) {
    pin_ptr<const wchar_t> wstr = PtrToStringChars(string);
    return (LPWSTR)wstr;
}

// Example
String^ s = "10.0.0.1";
LPWSTR psz = S2W(s);