MFC CString Format gives weird behaviour

I am having a weird problem with CString I have the following code which gives an unexpected result:

CString sourcePath = _T("C:\\some\\path\\file.ext");
CString log;
log.Format(_T("Path = %s"), sourcePath);

the result string shows Path = (null).

I am not sure what is going on under the hood there, I have tried casting the sourcePath to an LPCTSTR and got a valid pointer and when viewing the content o开发者_如何转开发f that memory address in the memory view window of MSVC everything seems valid.

this annoys me as I have tried the same method in previous projects and it worked pretty well.

Thanks.

P.S. Please, before people start commenting here asking about what is a CString, as it happened in an earlier post of mine, please check here first: MSDN CString

Edit: sorry about the slash thingy.. and yes the original code does have double slashes..

---

As your MSDN CString link also mentions, you cannot pass the CString itself to the Format function.

Use:

  log.Format(_T("Path = %s"), sourcePath.GetString());

---

The string "C:\some\path\file.ext" should be "C:\some\path\file.ext" - otherwise you will read control characters (\s \p \f) instead.

---

Depending on the MFC version and whether your app is built for win32 or x64, you might have to cast the CString:

log.Format(_T("Path = %s"), (LPCTSTR)sourcePath);

---

There is a problem in your sourcePath initialization. The character \ is a special character in C/C++. You should replace it with \ (double ) So the first line of code should be: CString sourcePath = _T("C:\\some\\path\\file.ext");

Hope this helps.