Parse string to LPCWSTR

Question

I am working with boost-filesystem to search all the files in a concrete path. I also want to retrieve this file's creation data, last opening and last update so as I am working in Windows I need to use the GetFileTime (which requires a HANDLE that I will get by the CreateFile function.

The point is that by boost filesystem I get a string such as

string filename="C:\Users\MyUser\Desktop\PDN.pdf";

and I need to convert this string to a LPCWSTR.

Because of this I have done several tries which have all failed, for example:

HANDLE hFile = CreateFile((LPCWSTR)fileName.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL);

But when doing this, it succeded:

HANDLE hFile = CreateFile(L"C:\\Users\\MyUSer\\Desktop\\PDN.pdf", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL);

So my question is, how could I parse a string to a PWSTR using a string variable? And if possible (I guess no), is there any function that will change the original path adding a slash where finds another slash?

Thanks a lot

EDITED: This is the way I have done it after what I have read in here:

wstring fileFullPathWstring = winAPII.stringToWstring(iter->path().string());

HANDLE hFile = CreateFile(fileFullPathWstring.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL);

Using the function:

wstring WinAPIIteraction::stringToWstring(string stringName){
    int len;
    int slength = (int)stringName.length() + 1;
    len = MultiByteToWideChar(CP_ACP, 0, stringName.c_str(), slength, 0, 0);
    wchar_t* buf = new wchar_t[len];
    MultiByteToWideChar(CP_ACP, 0, stringName.c_str(), slength, buf, len);
    std::wstring r(buf);
    delete[] buf;
    return r;
}

Answer 1

You can use MultibyteToWideChar() function to perform the actual conversion (MSDN page). There is no need to add slashes - they are just escape sequences which represent a single '\' in your program code.

Answer 2

Simplest solution:

wstring filename="C:\Users\MyUser\Desktop\PDN.pdf";
HANDLE hFile = CreateFile(
    fileName.c_str(), // std::wstring::c_str returns wchar_t*
    GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL);

Answer 3

Use CA2W from ATL for that:

string filename="C:\Users\MyUser\Desktop\PDN.pdf";
HANDLE hFile = CreateFile(CA2W(fileName.c_str()), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL);

Answer 4

I know that it´s late but this is a method I am using to convert a string into LPCWSTR:

typedef long long long64;
/**Don´t forget to use delete*/
LPCWSTR convStringToLPCWSTR(string String)
{
    char *cString = &String[0u];
    long64 size = strlen(cString);
    wchar_t* wString = new wchar_t[size];
    for (long64 i = 0; i < size; i++)
    {
        wString[i] = cString[i];
    }
    wString[size] = 0; //important, otherwise Windows will print whatever next in memmory until it finds a zero.
    return wString;
}