My Documents et al --- success

[Angus Leeming]

It turns out that Jürgen's suggested way to ascertain the different 
Windows folders is straightforward to implement. No need to use the .net 
framework; it all exists in the standard WinAPI.

Question. What should we do in the unlikely event that these calls fail? 
  Post a warning or terminate?

Angus
$g++ -o trial trial.C
$ ./trial
APPDATA is C:\Documents and Settings\Angus\Application Data
COMMON_APPDATA is C:\Documents and Settings\All Users\Application Data
PERSONAL is C:\Documents and Settings\Angus\My Documents
$ cat trial.C
#include <shlobj.h>
#include <iostream>
#include <string>
// Needed for MinGW:
#ifndef SHGFP_TYPE_CURRENT
# define SHGFP_TYPE_CURRENT 0
#endif
std::string const folder_path(int folder_id)
{
        char folder_path[MAX_PATH + 1];
        if (SUCCEEDED(SHGetFolderPath(0, folder_id, 0,
                                      SHGFP_TYPE_CURRENT, folder_path)))
                return folder_path;
        return std::string();
}
std::string const id_as_string(int folder_id)
{
        if (folder_id == CSIDL_APPDATA)
                return "APPDATA";
        if (folder_id == CSIDL_COMMON_APPDATA)
                return "COMMON_APPDATA";
        if (folder_id == CSIDL_PERSONAL)
                return "PERSONAL";
        return std::string();
}
void print_success(int folder_id)
{
        std::string const folder_name = folder_path(folder_id);
        std::string const id_str = id_as_string(folder_id);
        if (folder_name.empty())
                std::cout << "Unable to ascertain " << id_str
                          << " folder\n";
        else
                std::cout << id_str << " is " << folder_name << '\n';
}
int main()
{
        print_success(CSIDL_APPDATA);
        print_success(CSIDL_COMMON_APPDATA);
        print_success(CSIDL_PERSONAL);
        return 0;
}