Delphi string formatting in API header

I have a record field "devDesc.VendorIdOffset", a Cardinal (ULONG) value
translated from an API hearder. It is the byte offset to a zero-terminated
ascii string containing the device's vendor id string.
The string length is 8.

I'm using a record pointer so the value at @pdevDesc.VendorIdOffset is what
I want to get into string variable 'VendorID'.

I have tried
        VendorID := Copy(Pchar(@PdevDesc.VendorIdOffset),
PdevDesc.VendorIdOffset, 8)
and
        VendorID := Format('%p', [@PdevDesc.VendorIdOffset, 8,
@PdevDesc.VendorIdOffset])
neither produces a name ... the format() one results in a string of
charaters, the other one makes a blank.

These C/C++ routines work.
I can't figure out how to translate them into Delphi/pascal.

VOID DebugPrint( USHORT DebugPrintLevel, PCHAR DebugMessage, ... )
{
    va_list args;

    va_start(args, DebugMessage);

    if (DebugPrintLevel <= DebugLevel) {
        char buffer[128];
        (VOID) vsprintf(buffer, DebugMessage, args);
        printf( "%s", buffer );
    }

    va_end(args);
}

// this uses the function above to format 'devDesc.VendorIdOffset'
if ( devDesc->VendorIdOffset && p[devDesc->VendorIdOffset] ) {
                DebugPrint( 1, "Vendor ID       : " );
                for ( i = devDesc->VendorIdOffset; p[i] != (UCHAR) NULL && i
< returnedLength; i++ ) {
                    DebugPrint( 1, "%c", p[i] );
                }
                DebugPrint( 1, "
");
            }

Thanks for any help,

Bill Mudd