IO::Pager::Unbuffered - Pipe output to a pager if output is to a TTY

IO-Pager documentation Contained in the IO-Pager distribution.

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NAME

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IO::Pager::Unbuffered - Pipe output to a pager if output is to a TTY

SYNOPSIS

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  use IO::Pager::Unbuffered;
  {
    #local $STDOUT =     IO::Pager::Unbuffered::open *STDOUT;
    local  $STDOUT = new IO::Pager::Unbuffered       *STDOUT;
    print <<"  HEREDOC" ;
    ...
    A bunch of text later
    HEREDOC
  }

DESCRIPTION

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IO::Pager is designed to programmaticly decide whether or not to point the STDOUT file handle into a pipe to program specified in $ENV{PAGER} or one of a standard list of pagers.

new( [FILEHANDLE] )

Instantiate a new IO::Pager to paginate FILEHANDLE if necessary. Assign the return value to a scoped variable.

FILEHANDLE

Defaults to currently select()-ed FILEHANDLE.

open( [FILEHANDLE] )

An alias for new.

close( FILEHANDLE )

Explicitly close the filehandle, if a pager was deemed necessary this will kill it. Normally you'd just wait for the user to exit the pager and the object to pass out of scope.

This does not default to the current filehandle.

CAVEATS

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You probably want to do something with SIGPIPE eg;

  eval{
    $SIG{PIPE} = sub{ die };
    local $STDOUT = IO::Pager::open(*STDOUT);

    while(1){
      #Do something
    }
  }

  #Do something else

SEE ALSO

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IO::Pager, IO::Pager::Buffered, IO::Pager::Page

AUTHOR

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Jerrad Pierce <jpierce@cpan.org>

This module is forked from IO::Page 0.02 by Monte Mitzelfelt

Significant proddage provided by Tye McQueen.

LICENSE

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* Thou shalt not claim ownership of unmodified materials.
* Thou shalt not claim whole ownership of modified materials.
* Thou shalt grant the indemnity of the provider of materials.
* Thou shalt use and dispense freely without other restrictions.
IO-Pager documentation Contained in the IO-Pager distribution. 
package IO::Pager::Unbuffered;

use 5;
use strict;
use vars qw( $VERSION );
use Tie::Handle;

$VERSION = 0.05;

sub new(;$){
  no strict 'refs';
  my $FH = $_[1] || *{select()};

  #STDOUT & STDERR are seperately bound to tty
  if( defined( my $FHn = fileno($FH) ) ){
    if( $FHn == fileno(STDOUT) ){
      return 0 unless -t $FH;
    }
    if( $FHn == fileno(STDERR) ){
      return 0 unless -t $FH;
    }
  }
  #This allows us to have multiple pseudo-STDOUT
  return 0 unless -t STDOUT;

  tie($FH, $_[0], $FH) or die "Can't tie $$FH";
}

sub open(;$){
  new IO::Pager::Unbuffered;
}

sub TIEHANDLE{
  my $PAGER;

  unless( CORE::open($PAGER, "| $ENV{PAGER}") ){
    warn "Can't pipe to $ENV{PAGER}: $!\n";
    return 0;
  }

  bless [$_[1], $PAGER, 0], $_[0];
}

sub PRINT{
  my $ref = shift;
  CORE::print {$ref->[1]} @_;
}

sub PRINTF{
  PRINT shift, sprintf shift, @_;
}

sub WRITE{
  PRINT shift, substr $_[0], $_[2]||0, $_[1];
}


*DESTROY = *CLOSE;
sub CLOSE{
  local $^W = 0;
  my $ref = $_[0];
  return if $ref->[2]++;
  untie $ref->[0];

  close($ref->[1]);
}

1;
__END__