DLL Versions from C and VB

Listing 1: verres.c — Version extractor for C

//==============================================================
//
//  VerRes.cpp
//
//      GetDllVersion() - Returns the load path and version
//                        of a given file.
//      main() - test entry point
//      
//
//==============================================================

#include <windows.h>

//-- Windows Dynamic Data structure;  defined for what we know
typedef struct _VS_VERSIONINFO { 
WORD wLength; 
WORD wValueLength; 
WORD wType; 
WCHAR szKey[15];        //-- WCHAR / UNICODE string
WORD Padding1[1];       //-- this is actually dynamic
}VS_VERSIONINFO;

//--------------------------------------------------------------
//  GetDllVersion()
//      Returns the load path and version of the given file.
//
//      filename [in]  - root file name to get the version
//      loadpath [out] - buffer to write the full path
//      maxloadpath [in] - max size of loadpath[]
//      maj      [out]  - version major 
//      min      [out]  - version minor
//      rev      [out]  - version revision
//      bld      [out]  - version build number
//
//--------------------------------------------------------------
int GetDllVersion( char * filename, char * loadpath,
                    int maxloadpath, int *maj, int *min,
                    int *rev, int *bld )
{
    int bRetval = 0;    //-- 0 = failure
        HRSRC hRes;
        HGLOBAL hGbl;
        void * lpRes;
        char * p;
        VS_VERSIONINFO * pInf;
        VS_FIXEDFILEINFO * pInfo ;

    HINSTANCE hDll = LoadLibrary( filename );

    if( hDll )
    {
        //-- get the library's full path
        GetModuleFileName( hDll, loadpath, maxloadpath );

        //-- find the resource 
        hRes = FindResource( hDll, "#1", RT_VERSION);

        if( hRes )
        {
            hGbl = LoadResource( hDll, hRes );

            if( hGbl )
            {
                lpRes = LockResource( hGbl );

                if (lpRes )
                {    //--type cast to a version info
                     pInf = (VS_VERSIONINFO *)lpRes; 

                     if( pInf->wValueLength > 0 )
                     {
                         p = (char *) pInf->Padding1;

                         //-- cast to a VS_FIXEDFILEINFO
                         pInfo = (VS_FIXEDFILEINFO *)p;

                         while( (((long)p)&0x04) != 0 )
                         {
                             p++;
                             pInfo = (VS_FIXEDFILEINFO *)p;
                         }

                         //-- extract the version!

                         *maj = HIWORD(pInfo->dwFileVersionMS);
                         *min = LOWORD(pInfo->dwFileVersionMS);
                         *rev = HIWORD(pInfo->dwFileVersionLS);
                         *bld = LOWORD(pInfo->dwFileVersionLS);

                         bRetval = 1;   //-- 1 = success
                     }
                }
            }
        }

        FreeLibrary( hDll );
    }

    return bRetval;
}

//--------------------------------------------------------------
// main() for testing
//--------------------------------------------------------------

#include <stdio.h>

int main(int argc, char* argv[])
{
    char * pFilename;
    int maj, min, rev, bld;
    char loadpath[MAX_PATH];

    if( argc <= 1)
    {
        printf( "VerRes requires a filename ");
        printf( "as a parameter\r\n" );
        return -1;
    }

    pFilename = (char *)malloc( strlen(argv[1])+1 );

    if( pFilename )
    {
        //-- copy the filename argument
        strcpy( pFilename, argv[1] );   

        if (GetDllVersion( pFilename, loadpath, MAX_PATH,
                           &maj, &min, &rev, &bld ))
            printf( "Loaded version %d.%d.%d.%d from %s\r\n",
                     maj, min, rev, bld, loadpath );
        else
            printf( "error loading file %s\r\n", pFilename );

        free( pFilename );

    }
    else
        printf( "error allocating memory for file buffer\r\n" );


    return 0;
}

//End of File