There is a common mechanism for all descriptors, to check whether a descriptor is ready for reading/writing, please check out IO::Select.
The main point is to call can_read or can_write before you really go reading/writing. This way, you even don't need to bother blocking/non-blocking mode. More important, you gain a better control.
On the other hand, I attached a simple sample to show pipe:
parn.pl:
use strict;
use warnings;
$| ++;
print "Entering parn.pl...\n";
my $chld;
open($chld, "perl -w chld.pl|") || die "failed to open child process\n
+";
my @ready;
while (1) {
my $from_chld = <$chld>;
print $from_chld * 2, "\n";
}
chld.pl:
use strict;
use warnings;
$| ++;
while (<>) {
if ($_ < 100) {
print "$_";
}
}
Update: for getc, although it returns one char a time, but unfortunately, this only happens after return is hit. An alternative way is presented in perlfunc under getc.