FileVersion - Retrieve file version information

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Introduction

Getting the version information of a file is useful in many cases. Maybe you want to check the version of a library before you load it, to ensure not loading an old one which can result in unexpected software behaviour. Or you simply want to display the current version of your application in the About-box. This class allows you to do that in a very easy way.

Background

I'm going to develop an application which detects problems with duplicated libraries. It should notify me if an old library has been loaded instead of the new one because of the "Library Search Order". This class provides me the basic requirements for that, like determining or comparing file versions.

There are similar articles on the CodeProject already. I developed my own class to get a lightweight way to determine file versions without storing other information like company name, description, etc..

Using the code

The following samples demonstrate how to use this class.

Get the version of the current process

CString        strFileVersion;
FileVersion    cFileVersion;

// Get formated file version
cFileVersion.GetFileVersion( L"Version: %i.%i", strFileVersion );

Useful to keep your About dialog up-to-date:

Get the version of a specified file

CString        strFileVersion;
FileVersion    cFileVersion( L"C:\\Windows\\System32\\NativeHooks.dll" );

// Get file version
cFileVersion.GetFileVersion( strFileVersion );

MessageBox( strFileVersion );

Output:

Compare file versions

// Version is 6.1.7600.16385
FileVersion    cFileVersionNativeHooks( L"C:\\Windows\\System32\\NativeHooks.dll" );

// Version is 12.0.7600.16385
FileVersion    cFileVersionWmerror( L"C:\\Windows\\System32\\wmerror.dll" );

// Compare versions
bool bIsGreater =  ( cFileVersionNativeHooks > cFileVersionWmerror );  // false
bool bIsLess    =  ( cFileVersionNativeHooks < cFileVersionWmerror );  // true
bool bIsEqual    =  ( cFileVersionNativeHooks == cFileVersionWmerror ); // false

Interface

Constructors

• explicit FileVersion( const TCHAR * kstrFilePath ): Creates the FileVersion of the specified file.
• FileVersion() Creates the FileVersion: of the current process.

Methods

• bool IsValid() const: Returns whether the file version could be determined.
• unsigned short GetMajorVersion() const: Returns the Major Version.
• unsigned short GetMinorVersion() const: Returns the Minor Version.
• unsigned short GetReleaseNumber() const: Returns the Release Number.
• unsigned short GetBuildNumber() const: Returns the Build Number.
• bool GetFileVersion( const TCHAR* kstrFileFormat, CString& strFileVersion ) const: Gets the file version string. The order is Major, Minor, Release, and Build Number. The string can be formatted; for instance, L"Version: %i.%i.%i.%i" will return a string like "Version: 12.1.0.530".
• bool GetFileVersion( CString& strFileVersion ) const: Gets the file version string. The order is Major, Minor, Release, and Build number, with a dot in between. For example: "12.1.0.530".
• bool IsEqual( const FileVersion & krhs ) const: Returns true if the file version is equal to the passed file version.

Operations

• bool operator<( const FileVersion & krhs ) const: Returns true if the file version is less than the passed file version.
• bool operator>( const FileVersion & krhs ) const: Returns true if the file version is greater than the passed file version.
• bool operator==( const FileVersion & krhs ) const: Returns true if the file version is equal to the passed file version.

Implementation details

This is how the file version is determined:

bool FileVersion::DetermineFileVersion( const TCHAR* kstrFilePath )
{
    // Precondition
    if ( NULL == kstrFilePath )
        return false; // FilePath is empty, no file to determine version.

    DWORD    dwHandle;

    // Determines whether the operating system can retrieve version information
    // for a specified file.
    DWORD    dwFileVersionInfoSize = 
        GetFileVersionInfoSize( kstrFilePath, &dwHandle );

    if ( NULL == dwFileVersionInfoSize )
        return false;    // Can't retrieve version information size.

    // Allocate space to retrieve version information using vector to prevent
    // memory leaks
    std::vector<BYTE>    pData( dwFileVersionInfoSize );

    // Retrieves version information for the specified file.
    if ( false == GetFileVersionInfo( kstrFilePath
        , dwHandle
        , dwFileVersionInfoSize
        , static_cast<lpvoid>( &pData[0] ) ) )
        return false; // Can't retrieve version information.

    // The memory of ptFileInfo is freed when pData is freed.
    VS_FIXEDFILEINFO *ptFileInfo;
    UINT    uintSize;

    // Retrieves version information from the version-information resource
    if ( false == VerQueryValue( static_cast<lpvoid>( &pData[0] )
        , _T("\\")
        , reinterpret_cast<lpvoid*> ( &ptFileInfo )
        , &uintSize ) )
        return false; // Can't retrieve version information

    // Resolve major, minor, release and build number.
    musMajorVersion        = static_cast<unsigned>(  
        ( ptFileInfo->dwFileVersionMS >> 16 ) &0xffff );

    musMinorVersion        = static_cast<unsigned>( 
        ptFileInfo->dwFileVersionMS &0xffff );

    musReleaseNumber    = static_cast<unsigned>( 
        ( ptFileInfo->dwFileVersionLS >> 16 ) &0xffff);

    musBuildNumber        = static_cast<unsigned>( 
        ptFileInfo->dwFileVersionLS & 0xffff );

    return true;
}

Notes

This class compiles with UNICODE and ANSI at warning level 4.