Converting LPSTR to LPCWSTR

Question

I have two functions! The first one is

GetUserName(LPSTR buffer, LPDWORD size);

And

SetInfo(LPCWSTR user, int secret);

I have to take the output from GetUserName which is buffer as an LPSTR

Then I have to use that string in the SetInfo function as an LPCWSTR

My question is; What is the safest and best approach to doing this?

Can MultiByteToWideChar be used here? Thanks!

But the answer there doesn't demonstrate the use of `MultiByteToWideChar`. — Sebastian Redl, Oct 21 '14 at 08:01
Yes, you can use `MultiByteToWideChar`. Just look at the MSDN page for how to use it. — MicroVirus, Oct 21 '14 at 08:05

score 3 · Accepted Answer · answered Oct 21 '14 at 08:00

3

If the GetUserName function is the Windows API function then you can just explicitly call the wide version:

wchar_t buffer[100];
GetUserNameW(buffer,100);

answered Oct 21 '14 at 08:00

Sean

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I'm so silly for not opening up my eyes to this. It's what you get for hours of no sleep. Thanks man! – user3251225 Oct 21 '14 at 08:07

score 3 · Answer 2 · answered Oct 21 '14 at 08:30

The proper way to call many Windows API is to make a first call supplying an empty buffer and requesting the size. Then allocate the buffer and make the call.

Here is an example for GetUserNameW.

DWORD size = 0;
wstring name;

auto ret = GetUserNameW(nullptr, &size);
if(!ret && ERROR_INSUFFICIENT_BUFFER == ::GetLastError() && size > 0)
{
   wstring.resize(size);
   ret = GetUserNameW(&name[0], size);
}

Converting LPSTR to LPCWSTR

2 Answers2