Run Time Error #0 MSVS 2003, with COM

[grommit99]

Hi all,

This is my first post here. I am new to COM, but I have read through many postings trying to get to the bottom of this, to no avail. Here is my problem.

I get the error Run Time Error #0, value of ESP not properly saved.......

From what I can tell, there are two possible causes.

1. In the advanced tab, there are the calling options. cdecl, stdcall, etc....
Everything in every project is set to cdecl, so I don't think that is it.

2. Typecasting or otherwise improper variable initialization/casting.
Maybe. I don't know the first thing about COM, so maybe this is really dumb. This is code that used to work, and all of a sudden doesn't.

void GetPFPSDataPaths(std::vector<std::string> &aDataPaths)
    {
        aDataPaths.clear();
        CoInitialize(0);
        bool ComEstablished(true);
        try
        {
                      HRESULT hr;
 
        // Create our COM objects
        IMapSeriesRowsetPtr spMapSeries;
        hr = spMapSeries.CreateInstance(__uuidof(MapSeriesRowset));
        if (hr != S_OK)
                         throw _com_error(hr);        
 
        ICoverageRowsetPtr spCoverage;
        hr = spCoverage.CreateInstance(__uuidof(CoverageRowset));
        if (hr != S_OK)
                         throw _com_error(hr);        
 
        IDataSourcesRowsetPtr spDataSources;
    hr = spDataSources.CreateInstance(__uuidof(DataSourcesRowset));
                    if (hr != S_OK)
                   throw _com_error(hr);
 
I use the spDataSources for lots of things, and all is well. Then, these few lines happen:
 
   // attempt to grab all paths from the map data manager
           spCoverage->Initialize("cadrg");
 
           hr = spDataSources->SelectAll(TRUE);

The SelectAll is where it dies.

Is there a problem with how I initialized the spDataSources?
Any other ideas?

Thanks,
Grommit.

[weaknessforcats]

spCoverage->Initialize("cadrg");

"cadrg" is a char char string. COM uses Unicode. I would be suprised to see a method have a char* argument, I would expect to see an LPWSTR instead.

You don't check the HRESULT from spCoverage->Initialize("cadrg") to see if it worked.

Maybe try:

LPWSTR str = SysAllocString("cadrg");
spCoverage->Initialize(str);
 

If you use SysAllocString(), don't forget to use SysFreeString() to release the allocation.