mifflin has asked for the wisdom of the Perl Monks concerning the following question:
I have a program that may try to get data from the command line using
However, there may not be any input. How do I detect if there is any input so the read will not block? Something like...while (<>) { }
UPDATE:if (data is available then) { while (<>) { } } else { # do something else }
Here is what I ended up doing get the behavior I was looking for...
Now, now matter how the user wants to give my prog the data like...my $stdin = IO::Select->new(\*STDIN); open my $fh, '|-', $cmd or die $!; if (@ARGV || $stdin->can_read(0)) { while (<>) { print {$fh} $_ or die $!; } } else { print {$fh} "\n" or die $!; } close $fh or die $!;
or$ echo "text" | myprog
or$ myprog <<EOT some text EOT
I get text without blocking.$ myprog afile
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