How to convert std::string to LPCWSTR in C++ (Unicode)

If you are in an ATL/MFC environment, You can use the ATL conversion macro:

#include <atlbase.h>
#include <atlconv.h>

. . .

string myStr("My string");
CA2W unicodeStr(myStr);

You can then use unicodeStr as an LPCWSTR. The memory for the unicode string is created on the stack and released then the destructor for unicodeStr executes.

I prefer using standard converters:

#include <codecvt>

std::string s = "Hi";
std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>> converter;
std::wstring wide = converter.from_bytes(s);
LPCWSTR result = wide.c_str();

Please find more details in this answer: https://stackoverflow.com/a/18597384/592651

Update 12/21/2020 : My answer was commented on by @Andreas H . I thought his comment is valuable, so I updated my answer accordingly:

1. codecvt_utf8_utf16 is deprecated in C++17.
2. Also the code implies that source encoding is UTF-8 which it usually isn't.
3. In C++20 there is a separate type std::u8string for UTF-8 because of that.

But it worked for me because I am still using an old version of C++ and it happened that my source encoding was UTF-8 .

• After knowing that, the C++11-standard has rules for .c_str() method (maybe .data() too), which allows us to use const_cast,

(I mean, normally using const_cast may be dangerous)

• we can safely take "const" input parameter.
• Then finally, use "const_cast" instead of any unnecessary allocation and deletion.

std::wstring s2ws(const std::string &s, bool isUtf8 = true)
{
    int len;
    int slength = (int)s.length() + 1;
    len = MultiByteToWideChar(isUtf8 ? CP_UTF8 : CP_ACP, 0, s.c_str(), slength, 0, 0);
    std::wstring buf;
    buf.resize(len);
    MultiByteToWideChar(isUtf8 ? CP_UTF8 : CP_ACP, 0, s.c_str(), slength,
           const_cast<wchar_t *>(buf.c_str()), len);
    return buf;
}

std::wstring wrapper = s2ws(u8"My UTF8 string!");
LPCWSTR result = wrapper.c_str();

Note that we should use CP_UTF8 for C++'s string-literal, but in some cases you may need to instead use CP_ACP (by setting second parameter to false).

If you are using QT then you can convert to QString and then myqstring.toStdWString() will do the trick.

It's so easy, no need to apply any custom method. Try with this:

string s = "So Easy Bro"
LPCWSTR wide_string;

wide_string = CA2T(s.c_str());

I think, it will works.