NAME

       IO::CaptureOutput - capture STDOUT and STDERR from Perl code, subprocesses or XS

VERSION

       version 1.1104

SYNOPSIS

           use IO::CaptureOutput qw(capture qxx qxy);

           # STDOUT and STDERR separately
           capture { noisy_sub(@args) } \$stdout, \$stderr;

           # STDOUT and STDERR together
           capture { noisy_sub(@args) } \$combined, \$combined;

           # STDOUT and STDERR from external command
           ($stdout, $stderr, $success) = qxx( @cmd );

           # STDOUT and STDERR together from external command
           ($combined, $success) = qxy( @cmd );

DESCRIPTION

       This module is no longer recommended by the maintainer - see Capture::Tiny instead.

       This module provides routines for capturing STDOUT and STDERR from perl subroutines,
       forked system calls (e.g. "system()", "fork()") and from XS or C modules.

NAME

FUNCTIONS

       The following functions will be exported on demand.

   capture()
           capture \&subroutine, \$stdout, \$stderr;

       Captures everything printed to "STDOUT" and "STDERR" for the duration of &subroutine.
       $stdout and $stderr are optional scalars that will contain "STDOUT" and "STDERR"
       respectively.

       "capture()" uses a code prototype so the first argument can be specified directly within
       brackets if desired.

           # shorthand with prototype
           capture C< print __PACKAGE__ > \$stdout, \$stderr;

       Returns the return value(s) of &subroutine. The sub is called in the same context as
       "capture()" was called e.g.:

           @rv = capture C< wantarray > ; # returns true
           $rv = capture C< wantarray > ; # returns defined, but not true
           capture C< wantarray >;       # void, returns undef

       "capture()" is able to capture output from subprocesses and C code, which traditional
       "tie()" methods of output capture are unable to do.

       Note: "capture()" will only capture output that has been written or flushed to the
       filehandle.

       If the two scalar references refer to the same scalar, then "STDERR" will be merged to
       "STDOUT" before capturing and the scalar will hold the combined output of both.

           capture \&subroutine, \$combined, \$combined;

       Normally, "capture()" uses anonymous, temporary files for capturing output.  If desired,
       specific file names may be provided instead as additional options.

           capture \&subroutine, \$stdout, \$stderr, $out_file, $err_file;

       Files provided will be clobbered, overwriting any previous data, but will persist after
       the call to "capture()" for inspection or other manipulation.

       By default, when no references are provided to hold STDOUT or STDERR, output is captured
       and silently discarded.

           # Capture STDOUT, discard STDERR
           capture \&subroutine, \$stdout;

           # Discard STDOUT, capture STDERR
           capture \&subroutine, undef, \$stderr;

       However, even when using "undef", output can be captured to specific files.

           # Capture STDOUT to a specific file, discard STDERR
           capture \&subroutine, \$stdout, undef, $outfile;

           # Discard STDOUT, capture STDERR to a specific file
           capture \&subroutine, undef, \$stderr, undef, $err_file;

           # Discard both, capture merged output to a specific file
           capture \&subroutine, undef, undef, $mergedfile;

       It is a fatal error to merge STDOUT and STDERR and request separate, specific files for
       capture.

           # ERROR:
           capture \&subroutine, \$stdout, \$stdout, $out_file, $err_file;
           capture \&subroutine, undef, undef, $out_file, $err_file;

       If either STDOUT or STDERR should be passed through to the terminal instead of captured,
       provide a reference to undef -- "\undef" -- instead of a capture variable.

           # Capture STDOUT, display STDERR
           capture \&subroutine, \$stdout, \undef;

           # Display STDOUT, capture STDERR
           capture \&subroutine, \undef, \$stderr;

   capture_exec()
           ($stdout, $stderr, $success, $exit_code) = capture_exec(@args);

       Captures and returns the output from "system(@args)". In scalar context, "capture_exec()"
       will return what was printed to "STDOUT". In list context, it returns what was printed to
       "STDOUT" and "STDERR" as well as a success flag and the exit value.

           $stdout = capture_exec('perl', '-e', 'print "hello world"');

           ($stdout, $stderr, $success, $exit_code) =
               capture_exec('perl', '-e', 'warn "Test"');

       "capture_exec" passes its arguments to "system()" and on MSWin32 will protect arguments
       with shell quotes if necessary.  This makes it a handy and slightly more portable
       alternative to backticks, piped "open()" and "IPC::Open3".

       The $success flag returned will be true if the command ran successfully and false if it
       did not (if the command could not be run or if it ran and returned a non-zero exit value).
       On failure, the raw exit value of the "system()" call is available both in the $exit_code
       returned and in the $? variable.

         ($stdout, $stderr, $success, $exit_code) =
             capture_exec('perl', '-e', 'warn "Test" and exit 1');

         if ( ! $success ) {
             print "The exit code was " . ($exit_code >> 8) . "\n";
         }

       See perlvar for more information on interpreting a child process exit code.

   capture_exec_combined()
           ($combined, $success, $exit_code) = capture_exec_combined(
               'perl', '-e', 'print "hello\n"', 'warn "Test\n"
           );

       This is just like "capture_exec()", except that it merges "STDERR" with "STDOUT" before
       capturing output.

       Note: there is no guarantee that text printed to "STDOUT" and "STDERR" in the subprocess
       will be appear in order. The actual order will depend on how IO buffering is handled in
       the subprocess.

   qxx()
       This is an alias for "capture_exec()".

   qxy()
       This is an alias for "capture_exec_combined()".

SEE ALSO

       •   Capture::Tiny

       •   IPC::Open3

       •   IO::Capture

       •   IO::Utils

       •   IPC::System::Simple

SUPPORT

   Bugs / Feature Requests
       Please report any bugs or feature requests through the issue tracker at
       <https://github.com/dagolden/IO-CaptureOutput/issues>.  You will be notified automatically
       of any progress on your issue.

   Source Code
       This is open source software.  The code repository is available for public review and
       contribution under the terms of the license.

       <https://github.com/dagolden/IO-CaptureOutput>

         git clone https://github.com/dagolden/IO-CaptureOutput.git

AUTHORS

       •   Simon Flack <simonflk@cpan.org>

       •   David Golden <dagolden@cpan.org>

CONTRIBUTORS

       •   Mike Latimer <mlatimer@suse.com>

       •   Olivier Mengue <dolmen@cpan.org>

       •   Tony Cook <tony@develop-help.com>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2015 by Simon Flack and David Golden.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.