Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!sdd.hp.com!hplabs!hpcc05!hpyhde4!hpycla!hpcuhc!hpcupt3!defaria@hpcupt3.cup.hp.com
From: defaria@hpcupt3.cup.hp.com (Andy DeFaria)
Newsgroups: comp.lang.pascal
Subject: Re: Text Files, I/O Redirection
Message-ID: <45670018@hpcupt3.cup.hp.com>
Date: 22 May 91 16:46:52 GMT
References: <45670017@hpcupt3.cup.hp.com>
Organization: Hewlett Packard, Cupertino
Lines: 34

>/ hpcupt3:comp.lang.pascal / defaria@hpcupt3.cup.hp.com (Andy DeFaria) / 10:44 am  May 21, 1991 /
>I have been having three problems lately in TP:
>
>	1) How do you perform I/O redirection using  Exec?  I remember this
>	   being discussed  and had thought  that  my home-brewed shell did
>	   this properly  then  found out it doesn't and   the  posting has
>	   since timed out.   I thought that  I needed to  Exec Command.Com
>	   and specify the ">" or "|" options  in the Options parameter but
>	   this not working.
>
>	2) How do you get the name  of an open text file  from AFile : Text
>	   variable?
>
>	3) The  FileSize function  doesn't work on  Text files.  How  can I
>	   easily and  efficiently  get the FileSize  (in bytes) of  a Text
>	   file? 

I have solved #2 and #3.  The solution for #2 is to cast the Text file to a
TextRec  and extract  the Name field.   Unfortunately this Name field is an
ASCIIZ string (smells like a C string).  So:

	FileName := ASCIIZToString (TextRec (TextFile).Name);

Where ASCIIZToString is a function that converts the ASCIIZ  string to a TP
String. 

The solution to #3 is a little bit uglier but works.  Basically, I take the
Text file, get its name (see above), assign  it to a  File of Byte and call
FileSize  on that file (Oh  and don't forget to Close  the file).   I would
like to  come up  with a better method for  this.  I don't like opening and
closing files if  I can avoid it.  Perhaps  a  FindFirst would give me  the
information but I'm not sure if FindFirst would incur more overhead than an
Open/Filesize/Close.  Does anybody know?

Oh, and I'm still waiting for an answer to #1.