gnu@perl has asked for the wisdom of the Perl Monks concerning the following question:

I have a situation where a program sends notifications in a number of methods (STDOUT, mailx, to a log file). Any one of a any combination of methods could be selected for the output under various circumstances.

What I was wondering is if I could use one print statement and specify multiple file handles to direct the print to?

I do realize that I could put the file handles into and array and loop over it, but I want to know if there is truly a way to do it with one execution of one command. Thanks.

  • Comment on Printing to multiple file handles with one request

Replies are listed 'Best First'.
Re: Printing to multiple file handles with one request
by tadman (Prior) on Nov 19, 2002 at 15:36 UTC
    You should create a sub-routine that handles these for you. For example: 
    sub mprint
{
        my @fh;
        push(@fh, shift) while (ref($_[0]) eq 'GLOB');

        print $_ @_ foreach (@fh);
}

open($so, ">&STDOUT");
open($se, ">&STDERR");

mprint $se, $so, "This tests\n";

    [download]
    It's not quite as clean as the builtin, but it's pretty close. You could even group your filehandles together into array packages, so that it's tidier: 
    my @default = ($so);
my @log_and_print = ($log, $so);

mprint @default, "Standard message\n";
mprint @log_and_print, "This goes to log and screen\n";

    [download]
    Update:
    IO::Tee looks like a great way to do this as well, provided you can install your own modules.
[reply]
[d/l]
[select]
      Yeah, this is pretty much what I had done, I was hoping there was a way 'built in' to standard perl. Installing modules is a little difficult due to the position of management.

      Sometimes I don't state what I have already done because it seems to taint the responses from time to time. I like to see fresh ideas and very often some really cool stuff come up.

      Thanks for your help!

[reply]
Re: Printing to multiple file handles with one request
by RMGir (Prior) on Nov 19, 2002 at 15:35 UTC
    That looks like a job for IO::Tee.
    --
    Mike
[reply]
Re: Printing to multiple file handles with one request
by John M. Dlugosz (Monsignor) on Nov 19, 2002 at 15:53 UTC
    I usually use a sub, like tadman explains.

    But, if you have code that writes to a single file already, you can retrofit by using a tie'd file handle. Just implement the WRITE, PRINT, and PRINTF hooks to send to your multiple sources.

[reply]
Re: Printing to multiple file handles with one request
by jdporter (Paladin) on Nov 19, 2002 at 19:17 UTC
[reply]

Back to Seekers of Perl Wisdom