.\" Automatically generated by Pod::Man 4.11 (Pod::Simple 3.35) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "IO::Pager::Buffered 3pm" .TH IO::Pager::Buffered 3pm "2020-11-07" "perl v5.30.3" "User Contributed Perl Documentation" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" IO::Pager::Buffered \- Pipe deferred output to PAGER if destination is a TTY .SH "SYNOPSIS" .IX Header "SYNOPSIS" .Vb 8 \& use IO::Pager::Buffered; \& { \& local $token = IO::Pager::Buffered::open local *STDOUT; \& print <<" HEREDOC" ; \& ... \& A bunch of text later \& HEREDOC \& } \& \& { \& # You can also use scalar filehandles... \& my $token = IO::Pager::Buffered::open($FH) or warn($!); \& print $FH "No globs or barewords for us thanks!\en" while 1; \& } \& \& { \& # ...or an object interface \& my $token = new IO::Pager::Buffered; \& \& $token\->print("OO shiny...\en") while 1; \& } .Ve .SH "DESCRIPTION" .IX Header "DESCRIPTION" IO::Pager subclasses are designed to programmatically decide whether or not to pipe a filehandle's output to a program specified in \fI\s-1PAGER\s0\fR; determined and set by IO::Pager at runtime if not yet defined. .PP This subclass buffers all output for display until execution returns to the parent scope or a manual flush occurs. If this is not what you want look at another subclass such as IO::Pager::Unbuffered. While probably not common, this may be useful in some cases, such as buffering all output to \s-1STDOUT\s0 while the process occurs so that warnings on \s-1STDERR\s0 are more visible, then displaying the less urgent output from \s-1STDOUT\s0 after. Or, alternately, letting output to \s-1STDOUT\s0 slide by and defer warnings for later perusal. .SH "METHODS" .IX Header "METHODS" Class-specific method specifics below, others are inherited from IO::Pager. .SS "open( [\s-1FILEHANDLE\s0] )" .IX Subsection "open( [FILEHANDLE] )" Instantiate a new IO::Pager to paginate \s-1FILEHANDLE\s0 if necessary. \&\fIAssign the return value to a scoped variable\fR. Output does not occur until the filehandle is flushed or closed. .SS "new( [\s-1FILEHANDLE\s0] )" .IX Subsection "new( [FILEHANDLE] )" Almost identical to open, except that you will get an IO::Handle back if there's no \s-1TTY\s0 to allow for IO::Pager agnostic programming. .SS "close( \s-1FILEHANDLE\s0 )" .IX Subsection "close( FILEHANDLE )" Flushes the buffer to the pager and closes the filehandle for writing. Normally, when using a lexically or locally scoped variable to hold the token supplied by open, explicit calls to close are unnecessary. However, if you are using IO::Pager::Buffered with an unlocalized \s-1STDOUT\s0 or \s-1STDERR\s0 you close the filehandle to display the buffered content or wait for global garbage cleaning upon program termination. .PP Alternatively, you might prefer to use a non-core filehandle with IO::Pager, and call \*(L"select\*(R" in perlfunc to make it the default for output. .SS "tell( \s-1FILEHANDLE\s0 )" .IX Subsection "tell( FILEHANDLE )" Returns the size of the buffer in bytes. .SS "flush( \s-1FILEHANDLE\s0 )" .IX Subsection "flush( FILEHANDLE )" Immediately flushes the contents of the buffer. .PP If the last print did not end with a newline, the text from the preceding newline to the end of the buffer will be flushed but is unlikely to display until a newline is printed and flushed. .SH "CAVEATS" .IX Header "CAVEATS" If you mix buffered and unbuffered operations the output order is unspecified, and will probably differ for a \s-1TTY\s0 vs. a file. See perlfunc. .PP \&\fI$,\fR is used see perlvar. .PP You probably want to do something with \s-1SIGPIPE\s0 eg; .PP .Vb 3 \& eval { \& local $SIG{PIPE} = sub { die }; \& local $STDOUT = IO::Pager::open(*STDOUT); \& \& while (1) { \& # Do something \& } \& } \& \& # Do something else .Ve .SH "SEE ALSO" .IX Header "SEE ALSO" IO::Pager, IO::Pager::Unbuffered, IO::Pager::Page, .SH "AUTHOR" .IX Header "AUTHOR" Jerrad Pierce .PP Florent Angly .PP This module was inspired by Monte Mitzelfelt's IO::Page 0.02 .SH "COPYRIGHT AND LICENSE" .IX Header "COPYRIGHT AND LICENSE" Copyright (C) 2003\-2018 Jerrad Pierce .IP "\(bu" 4 Thou shalt not claim ownership of unmodified materials. .IP "\(bu" 4 Thou shalt not claim whole ownership of modified materials. .IP "\(bu" 4 Thou shalt grant the indemnity of the provider of materials. .IP "\(bu" 4 Thou shalt use and dispense freely without other restrictions. .PP Or, if you prefer: .PP This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.0 or, at your option, any later version of Perl 5 you may have available.