OpenEuphoria

Re: Stumped by open("PRN","w")

• Posted by Dan B Moyer <DANMOYER at PRODIGY.NET> Jan 21, 2001
• 622 views

cense,

>From the Euphoria refmanual, on "open",

<begin quote>
Some typical devices that you can open are:

"CON" - the console (screen)
"AUX" - the serial auxiliary port
"COM1" - serial port 1
"COM2" - serial port 2
"PRN" - the printer on the parallel port
"NUL" - a non-existent device that accepts and discards output

<end quote>

So, "PRN" is a device definition of the printer on the parallel port.


Dan Moyer


----- Original Message -----
From: "cEnsE" <cense at MAIL.RU>
To: <EUPHORIA at LISTSERV.MUOHIO.EDU>
Sent: Sunday, January 21, 2001 7:15 PM
Subject: Re: Stumped by open("PRN","w")


> On Sun, 21 Jan 2001, Jim wrote:
> >> The following code snippet is from a Windows program using Win32Lib.ew.
If I run it with exw.exe, on a machine with no
> >> printer (or anything else) attached to the parallel port, it executes
the open("PRN","w") statement and assigns a valid
> >> file handle (4), where  I would have expected a -1.  It also continues
to the puts(ThePrinter,line) and executes that.
> >> In fact, under exw, the program runs to normal completion, when I would
have expected an abnormal termination.
> >>
> >> The very same code, copied to an .ex file, and run under ex.exe
executes in the same way, but then crashes with a DOS
> >> Critical Error when it hits the puts(ThePrinter,line) statement. In
both versions, I would have expected a -1 on the
> >> open for the non-existent printer.
> >>
> >> Can someone help me understand what I'm doing wrong here?
> >>
> >> Thanks.
> >>
> >> Totally perplexed.
> >>
> >> Jim
> >>
> >> ------------------- <begin code >
> >> object  line
> >> integer Patterns,ThePrinter,result
> >>
> >>           Patterns=open( "PATTERNS.TXT","rb" )        -- any text file
of 80 or more char.
> >>           if Patterns = -1  then
> >>              result = message_box( "Open Patterns.txt FAILED in
OnClick_ButtonPrint. Aborting. ","ERROR!", {} ) abort(1)
> >>
> >>           end if
> >>
> >>           ThePrinter = open("PRN","w")
>
> What exactly is this "PRN" ? the way you have it coded, if im not
mistaken,
> the open call will open a file in the current directory called PRN. I may
> very well be mistaked but from a quick look over this "PRN" stands out as
a
> possible  source of your problem.
>
>
> >>           if ThePrinter = -1  then
> >>              result = message_box( "Unable to find a printer;
skipping.", "ERROR!", {} )   -- never executed, although
> >> no printer
> >>           else
> >>              while 1 do
> >>                    line=gets(Patterns)
> >>                    if atom(line) then
> >>                       close(Patterns)
> >>                       close(ThePrinter)
> >>                       exit
> >>                    end if
> >>                    line=line[1..80]&"\n"
> >>                    puts(ThePrinter,line)    --   processed OK under
exw.exw ; crashes to DOS under ex.exe
> >>              end while
> >>           end if
> >> ---------< end code >
>
> I hope that helps, but if not, i tried.
>
> --
> evil, corruption and bad taste
> ^[cense]