How to use replaygain.dll in Microsoft VC++

Hi,

I'm using version 1.4.3

I have successfuly compiled replaygain.dll and I called
ChangeGainOfMP3File that works ok, because there is
file parameter in function.

But , for example I want to use function
InitGainAnalysis, but there is no file parameter?!

What I dont understand, how to use other function from
dll as is declared in replaygaindll.def, because I can't see
that those function are working with file handles.
How to use those function when ther is no file paramater
declared in function to open Mp3's.

I would like to know for howmuch I need to adjust
volume and how to do that with replaygain dll.
Is this possible at all, and how to do that?

Can I write Mp3Gain tags with this dll?
Some real example would be nice.

Thanks in advance

InitGainAnalysis @1
InitGainAnalysisAsInt @8
ResetSampleFrequency @9
AnalyzeSamples @2
AnalyzeSamplesInterleaved @5
GetRadioGain @3
GetTitleGain @6
GetAudiophileGain @4
GetAlbumGain @7
attachmsgpump @302
GetMP3GainErrorStrLen @303