C/C++ Copy file with automatic recursive folder/directory creation

Question

In Win32 API, there is CopyFile that literally copies a file. However, this API doesn't create folders. For example, I'd like to copy C:\Data\output.txt to D:\Temp\Data\output.txt. But, the target folders, D:\Temp and D:\Temp\Data', do not exist. In this case, this API just fails.

Is there a handy API that can automatically and recursively create directory structure on copy? Definitely, I can make such function, but I expect someone already made the function.

Answer 1

SHFileOperation should do the trick. From MSDN:

Copy and Move operations can specify destination directories that do not exist. In those cases, the system attempts to create them and normally displays a dialog box to ask the user if they want to create the new directory. To suppress this dialog box and have the directories created silently, set the FOF_NOCONFIRMMKDIR flag in fFlags.

Answer 2

You can achieve desired result using SHCreateDirectoryEx. Here is an example:

inline void EnsureDirExists(const std::wstring& fullDirPath)
{
    HWND hwnd = NULL;
    const SECURITY_ATTRIBUTES *psa = NULL;
    int retval = SHCreateDirectoryEx(hwnd, fullDirPath.c_str(), psa);
    if (retval == ERROR_SUCCESS || retval == ERROR_FILE_EXISTS || retval == ERROR_ALREADY_EXISTS)
    return; //success

    throw boost::str(boost::wformat(L"Error accessing directory path: %1%; win32 error code: %2%") 
       % fullDirPath
       % boost::lexical_cast<std::wstring>(retval));

    //TODO *djg* must do error handling here, this can fail for permissions and that sort of thing
}