Relatively new Perl programmer
Using gchar() and sleep() functions
to 'tickertape' the contents of a text file across the screen. (one char per second)

ie .. read a character from the file, print to screen, sleep, continue the loop.

Code I'm using ..
..
While !EOF(Infile)
{
$a=getc(infile) ;
print "$a" ;
sleep(1) :
}
..

But what happens is it seems to sleep for a while,
then suddenly print all chars to end of line
then sleep again,
then all of next line appears .. et seq.
Sleep time each time seems to be linelength.secs.


Am I using function wrongly,
or am I using wrong function?
especially if I want to do it at subsecond repeat rate,
eg 3 chars per second.

Advice appreciated.

Grif

Hi,

Perl buffers it's output by default, you need to turn that off first. I.e:

open(INFILE, $infile) or die "Cannot open $infile ($!)";
$| = 1; # make output unbuffered.

There are some other things in your code snippet that are not ok:
While !EOF(Infile) => while (<INFILE>)
sleep(1) : => sleep(1) ;

Hope this gets you going again.

It don't look much like perl, what's EOF?

What you are trying is actually quite awkward.
file reads/writes are generally buffered.
i.e. the OS likes to grab and print in blocks
to save disk/terminal operations as they are quite expensive.
output is usually line buffered. It likes to print a line
at a time.

you need to set auto flush otherwise printing is buffered
i.e. saves chars until a new line char

try this: