Jenda -
Thank you for you very clear explanation.
Dick Fell
Jenda Krynicky wrote:
>
> From: richard noel fell <[EMAIL PROTECTED]>
>
> > Here is an abridged version of what I am trying to do which is:
> > 1) write to a file in one subroutine
> > 2) write the contents of the original file to another file in a
> > separate subroutine.
> >
> > However, I get the error message:
> >
> > Use of uninitialized value in string at ./scratch2.pl line 24, <In1>
> > line 1. Use of uninitialized value in string at ./scratch2.pl line 24,
> > <In1> line 2. ...
> >
> > I cannot figure out what is happening. Can anyone explain this
> > behavior to me? Thanks, Dick Fell
> >
> > sub print_out{
> > open In1,"/home/rfell/tutoring/beaven/webproject/tmp/in.tmp"
> > or die "Cannot open in.tmp:$!";
> > open Out1, ">/home/rfell/tutoring/beaven/webproject/tmp/out.tmp"
> > or die "Cannot open out.tmp:$!";
> > while(defined<In1>){
> > print Out1 "$_"; }
> > }
>
> The problem is in the while() { line.
> If you write this :
>
> while (<In1>) {
>
> then the lines are read from In1 one by one and stored in $_.
> As soon as there is nothing more to read, the loop ends.
>
> But the automatic assignment to $_ ONLY works if there is nothing
> else in the loop condition but the <FILEHANDLE>. So the
>
> while (defined <In1>) {
>
> reads a line from In1, tests whether there was a line to read and
> throws away the line it read. And $_ is not even touched.
>
> Jenda
>
> P.S.: DO NOT USE
> print "$_";
> or
> print "$variable";
> Do not enclose variable names in quotes unless there is some
> more text into which you want to insert the variable value.
>
> =========== [EMAIL PROTECTED] == http://Jenda.Krynicky.cz ==========
> There is a reason for living. There must be. I've seen it somewhere.
> It's just that in the mess on my table ... and in my brain
> I can't find it.
> --- me
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