Re: Reading/writing LPT1

[tmoran@bix.com]

>Does anyone know how to read /write from the parallellport in Ada?  I
>have a program written in Basic that modifys the some bit's on LPTx but
>I want to re-write this program to Ada.
   I presume you are running under DOS or perhaps Windows xx or OS/2 or
Linux on an Intel box?  So we will assume your hardware is the standard
sort of LPT port for such a box, and your OS allows you direct IO
operations to the port, as opposed to, say, a machine running the flight
controls on a jet.  Since IO is so widely varied across different
systems, it's not included in the Ada standard.  Your compiler vendor,
however, almost surely supplies a library that will do hardware level IO
on your target platform.  If that's not the case, then you can a) link
in appropriate subroutines written in asm or C or perhaps even Basic and
call them from your Ada program, or b) use your compiler's
implementation of standard package System.Machine_Code.  For handling
the bits in, eg, the status result, either use a record representation
clause to give names to individual bits or bit fields, or (more error
prone) use type "mod 256" and do "and"s and "or"s.