🚀 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

Thanks for the Info!

You got me thinking about why the GetEnvironmentVariable wouldn't work... I
did a little searching and found that there is a name conflict between
Microsoft API and Borland's SysUtils.  In the process though, I found a
shorter version of your GetEnvVar in a post by Jeff Overcash (TeamB):

AnsiString __fastcall MyGetEnvironmentVariable(const AnsiString Name)
{
  int Len = GetEnvironmentVariable(Name.c_str(), NULL, 0);
  AnsiString Result;
  if (Len > 0)
  {
    Result.SetLength(Len - 1);
    GetEnvironmentVariable(Name.c_str(), Result.c_str(), Len);
  }
  return Result;
}



"Giuliano" <gcardinali@remove.adhoc.net> wrote in message
news:9e22cvsvi3d21vqgf4st59e9u1cr5r4luc@4ax.com...
> 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

"Bruce Henderson" <Bruce@CreativeControlSystems.com> wrote in message
news:3ec1031f@newsgroups.borland.com...
> What is the best way to resolve variables like
> %SystemRoot%, %HomeDrive%, %Temp%,
> %UserName%, etc?

Use the ExpandEnvironmentStrings() function.


Gambit

Thanks Remy!

I stumbled upon that one too...  But I also found out that if I use
ShellExecuteEx instead of ShellExecute, there is a fMask that can be set to
SEE_MASK_DOENVSUBST, that does it automatically.


"Remy Lebeau (TeamB)" <gambit47@yahoo.com> wrote in message
news:3ec11f4d$1@newsgroups.borland.com...
>
> "Bruce Henderson" <Bruce@CreativeControlSystems.com> wrote in message
> news:3ec1031f@newsgroups.borland.com...
> > What is the best way to resolve variables like
> > %SystemRoot%, %HomeDrive%, %Temp%,
> > %UserName%, etc?
>
> Use the ExpandEnvironmentStrings() function.
>
>
> Gambit
>
>