[MacPerl] Afraid to ask...

["Jay Bedsole" <rwdd30@email.sps.mot.com>]

This seems like a newbie question, but I can't seem to
find any documentation that will help me out. So at the
risk of ridicule, here goes. I've got this bit of code
that looks something like this:


while (<IN>) {           #IN is an arbitrary text file
    chomp;
    print "$_\n";        #STDOUT has been redirected
}


I know it's lame, but it's just to illustrate a point. My
(possibly naive) understanding is that perl should read
one line at a time into $_ each time through the loop. I'm
pretty sure I don't have a line end problem, BTW. That was
the first thing I checked.

My problem seems to be with input buffering. This works OK
for reasonably small files (I've run it successfully on a 2MB
file). However, for sufficiently large files (on a 45MB file in
particular), I get a problem. MacPerl runs out of memory and
terminates the script, but the output file will only contain a
few hundred lines. It seems that MacPerl is trying to read the
whole file into a buffer asynchronously, even though the script
is processing only one line at a time...

I know how to turn off output buffering, but what about
input buffering? Changing MacPerl's partition will probably
work, but doesn't seem the right solution and wouldn't work
for any arbitrary length file. I'm pretty sure I wouldn't
have this problem with sysread (right?), but that will add
quite a bit of complexity to my code, I think. Is there a
simple answer that I've just overlooked?

I've tried to see if perl on one of our unix boxes has the
same problem, but it's a bit difficult to emulate with a
GByte of RAM and virtual memory to boot!!!

jay

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