IPersistFile::Save method keeps failing to save the shortcut - c++

Question

I am trying to save a shortcut to my application in the startup folder. It all compiles, but it fails to actually save the game. The error seems to occur at hres = ppf->Save(wsz, TRUE);, where hres is set to -2147024891. If that means something specific, I haven't discovered what yet. My code is copied almost verbatim from MSDN, so I'm pretty confused why it isn't working. Perhaps I don't have permission to save a shortcut to the startup folder? Then again, I am also fairly new to all this, so it might be some basic error I am making. I am copying in all my #includes as well in case that is the problem.
Edit:
First, to avoid confusion, this is CLI based C++.
Checking hres for errors is just part of the MDSN code. This is really almost the exact same code from the website example. I have put in breakpoints, which is how I know that hres becomes -2147024891 right after the line hres = ppf->Save(wsz, TRUE); is run.
In case these are wrong, mediaMaestroLocation is set to "C:\Users\Keith\Documents\Visual Studio 2012\Projects\MediaMaestro\Debug\MediaMaestro.exe" and startupDestination is "C:\Users\Keith\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup". While the exe location looks great, I wonder if it matters that there isn't a \ after the destination folder path. I would have checked it already, but I need to spend a couple minutes figure out how to do it first.
#include <windows.h>
#include <string>
#include <stdio.h>
#include <shobjidl.h>
#include <shlobj.h>
#include "objbase.h"
#include <objidl.h>
#include <shlguid.h>
#include <winnls.h>
#using <System.dll>
#using <System.Windows.Forms.dll>
using namespace System;
using namespace System::Windows::Forms;
char startupDestination[MAX_PATH];
char mediaMaestroLocation[MAX_PATH];
DWORD nChars = 0;
BOOL yChars = 0;
HRESULT CreateLink()
{
CoInitializeEx( NULL, 0 );
HRESULT hres = 0;
IShellLink* psl;
if (SUCCEEDED(hres))
{
// Get a pointer to the IShellLink interface. It is assumed that CoInitialize
// has already been called.
hres = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER, IID_IShellLink, (LPVOID*)&psl);
if (SUCCEEDED(hres))
{
IPersistFile* ppf;
// Set the path to the shortcut target and add the description.
psl->SetPath(mediaMaestroLocation);
psl->SetDescription("Media Maestro");
// Query IShellLink for the IPersistFile interface, used for saving the
// shortcut in persistent storage.
hres = psl->QueryInterface(IID_IPersistFile, (LPVOID*)&ppf);
if (SUCCEEDED(hres))
{
WCHAR wsz[MAX_PATH];
// Ensure that the string is Unicode.
MultiByteToWideChar(CP_ACP, 0, startupDestination, -1, wsz, MAX_PATH);
// Add code here to check return value from MultiByteWideChar
// for success.
// Save the link by calling IPersistFile::Save.
hres = ppf->Save(wsz, TRUE);
ppf->Release();
}
psl->Release();
}
}
CoUninitialize();
return hres;
}
Here is the click event in the UI that calls the function:
void settingsLaunchOnStart_Click( Object^ Sender, EventArgs^ e )
{
if (settingsLaunchOnStart->Checked == false)
{
HRESULT r;
nChars = GetModuleFileName( NULL, mediaMaestroLocation, sizeof(mediaMaestroLocation) );
yChars = SHGetFolderPath( NULL, CSIDL_STARTUP, NULL, SHGFP_TYPE_CURRENT, startupDestination);
r = CreateLink();
}
else if (settingsLaunchOnStart->Checked == true)
{
//code to remove the shortcut
}
}
Is there something I am missing?

Answer 1

It turns out that it wasn't enough to name the output folder path, I had to name the file and extension as well. It seems strange to me, considering I don't think I have seen a single other example doing this. Anyway, here is my updated working code:
HRESULT CreateLink()
{
CoInitializeEx( NULL, 0 );
HRESULT hres = 0;
IShellLink* psl;
if (SUCCEEDED(hres))
{
// Get a pointer to the IShellLink interface. It is assumed that CoInitialize
// has already been called.
hres = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_ALL, IID_IShellLink, (LPVOID*)&psl); //CLSCTX_ALL CLSCTX_INPROC_SERVER (void**)&psl (LPVOID*)&psl
if (SUCCEEDED(hres))
{
IPersistFile* ppf;
// Set the path to the shortcut target and add the description.
psl->SetPath(mediaMaestroLocation);
psl->SetDescription(L"Media Maestro");
psl->SetIconLocation(mediaMaestroLocation, 0);
// Query IShellLink for the IPersistFile interface, used for saving the
// shortcut in persistent storage.
hres = psl->QueryInterface(IID_IPersistFile, (LPVOID*)&ppf); //(void**)&psl (LPVOID*)&ppf
if (SUCCEEDED(hres))
{
WCHAR wsz[MAX_PATH];
// Save the link by calling IPersistFile::Save.
hres = _wmakepath_s( wsz, _MAX_PATH, NULL, startupDestination,
L"MediaMaestro", L"lnk" );
hres = ppf->Save(wsz, TRUE);
ppf->Release();
}
psl->Release();
}
}
CoUninitialize();
return hres;
}
The addition of _wmakepath_s lets me append the name of my program and its extension onto the filepath I got from SHGetFolderPath. Once I feed that into the IPersistFile interface it saves as it should.

Answer 2

you have only initialized hres to 0 and then ur checking if it succeded ? u are never realling declaring it somewhere, and -2147024891 probably means that the variable is not initialized yet.
a wild guess is that it never even reahes the: hres = ppf->Save(wsz, TRUE); line and therefore it is not initialized :P try putting out some breakpoints when debugging and maybe use some watches to peek into variables :)
Best regards.