🚀 go-pugleaf

On Tue, 13 May 2003 09:36:51 -0500, "Bruce Henderson"
<Bruce@CreativeControlSystems.com> wrote:

>What is the best way to resolve variables like %SystemRoot%, %HomeDrive%,
>%Temp%, %UserName%, etc?
>
>Is there an API to do this?  Do I have to pull them out of the Registry?
>What about different version of Windows?
>

Hi,

    you can use the Windows' API GetEnvironmentVariable.

For example, you can write an utility function like the following:

AnsiString GetEnvVar( AnsiString VarName )
{
    const int Len = GetEnvironmentVariable( VarName.c_str(), 0, 0 );
    if ( Len ) {
        class TBuffer {
        public:
            TBuffer( int Len ) : Buffer_( new char[Len] ) {}
            ~TBuffer() throw() { delete [] Buffer_; }
            char* const operator()( void ) const { return Buffer_; }
        private:
            TBuffer( const TBuffer& );
            TBuffer& operator=( const TBuffer& );
            char* const Buffer_;
        } Buffer( Len );

        GetEnvironmentVariable( VarName.c_str(), Buffer(), Len );
        return Buffer();
    }
    return AnsiString();
}

then using it in the following manner:

    ShowMessage( GetEnvVar( "SystemRoot" ) );

Note, you have to strip out the % signs for variable like %SystemRoot%,
%HomeDrive%, %Temp%, %UserName%, etc.

There's also a GetEnvironmentVariable at VCL level

AnsiString__fastcall GetEnvironmentVariable(const AnsiString Name);

but, AFAIK, you can't link to it with BCB6.

Hope this helps.

Giuliano