TFDDs - customizing `writeln' (Was: Legal Change in GPC ?)

Sat, 3 May 1997 23:44:55 +0200 (MET DST)

According to Frank Heckenbach:
> 
> Indeed, I'd like to have something like this in gpc, too. I'm not at all
> familiar with the internals of "Text" files (or other files) in gpc.
> (ISTR, it has something to do with "bindable" variables, but I don't know
> much about those, either.)
>
> [...]
>
> The particular syntax (and other things) BP uses for this is, IMHO, not very
> nice (it was introduced after the "good days" of Borland, but before the
> introduction of OOP, which could have simplified things), so I don't vote
> for copying BP's mechanism. But any way to do such things would be good.

If somebody who knows C wants to implement this for GPC, here are
some ideas:

GPC's run time system (RTS) defines a function `_p_write' which
is responsible for all output to text files.  The C source is in
`rts/rts-write.c'.

I already modified this function to call `cprintf' instead of `printf'
on the DOS platform if the variable `_p_directvideo' has a nonzero value.
This is done through some preprocessor macros PRINTF1, ... PRINTF4,
CFWRITE and serves the purpose to make a `CRT' Unit for DOS possible.

If you replace my macro calls by a call to `sprintf' followed by an
indirect call to an output function, we've got it.  (Note that Pascal
allows `chr ( 0 )' characters in Strings.)

Happy hacking,

    Peter

  Dipl.-Phys. Peter Gerwinski, Essen, Germany, free physicist and programmer
peter.gerwinski@uni-essen.de - http://home.pages.de/~peter.gerwinski/ [970201]
 maintainer GNU Pascal [970420] - http://home.pages.de/~gnu-pascal/ [970125]

Peter Gerwinski (peter@agnes.dida.physik.uni-essen.de)