errno5.18(3pm) [mojave man page]

Errno(3pm)						 Perl Programmers Reference Guide						Errno(3pm)

NAME

       Errno - System errno constants

SYNOPSIS

	   use Errno qw(EINTR EIO :POSIX);

DESCRIPTION

       "Errno" defines and conditionally exports all the error constants defined in your system "errno.h" include file. It has a single export
       tag, ":POSIX", which will export all POSIX defined error numbers.

       "Errno" also makes "%!" magic such that each element of "%!" has a non-zero value only if $! is set to that value. For example:

	   use Errno;

	   unless (open(FH, "/fangorn/spouse")) {
	       if ($!{ENOENT}) {
		   warn "Get a wife!
";
	       } else {
		   warn "This path is barred: $!";
	       }
	   }

       If a specified constant "EFOO" does not exist on the system, $!{EFOO} returns "".  You may use "exists $!{EFOO}" to check whether the
       constant is available on the system.

CAVEATS

       Importing a particular constant may not be very portable, because the import will fail on platforms that do not have that constant.  A more
       portable way to set $! to a valid value is to use:

	   if (exists &Errno::EFOO) {
	       $! = &Errno::EFOO;
	   }

AUTHOR

       Graham Barr <gbarr@pobox.com>

COPYRIGHT

       Copyright (c) 1997-8 Graham Barr. All rights reserved.  This program is free software; you can redistribute it and/or modify it under the
       same terms as Perl itself.

perl v5.18.2							    2017-10-07								Errno(3pm)

IO::Pipe(3pm)						 Perl Programmers Reference Guide					     IO::Pipe(3pm)

NAME

       IO::Pipe - supply object methods for pipes

SYNOPSIS

	       use IO::Pipe;

	       $pipe = IO::Pipe->new();

	       if($pid = fork()) { # Parent
		   $pipe->reader();

		   while(<$pipe>) {
		       ...
		   }

	       }
	       elsif(defined $pid) { # Child
		   $pipe->writer();

		   print $pipe ...
	       }

	       or

	       $pipe = IO::Pipe->new();

	       $pipe->reader(qw(ls -l));

	       while(<$pipe>) {
		   ...
	       }

DESCRIPTION

       "IO::Pipe" provides an interface to creating pipes between processes.

CONSTRUCTOR

       new ( [READER, WRITER] )
	   Creates an "IO::Pipe", which is a reference to a newly created symbol (see the "Symbol" package). "IO::Pipe::new" optionally takes two
	   arguments, which should be objects blessed into "IO::Handle", or a subclass thereof. These two objects will be used for the system call
	   to "pipe". If no arguments are given then method "handles" is called on the new "IO::Pipe" object.

	   These two handles are held in the array part of the GLOB until either "reader" or "writer" is called.

METHODS

       reader ([ARGS])
	   The object is re-blessed into a sub-class of "IO::Handle", and becomes a handle at the reading end of the pipe. If "ARGS" are given
	   then "fork" is called and "ARGS" are passed to exec.

       writer ([ARGS])
	   The object is re-blessed into a sub-class of "IO::Handle", and becomes a handle at the writing end of the pipe. If "ARGS" are given
	   then "fork" is called and "ARGS" are passed to exec.

       handles ()
	   This method is called during construction by "IO::Pipe::new" on the newly created "IO::Pipe" object. It returns an array of two objects
	   blessed into "IO::Pipe::End", or a subclass thereof.

SEE ALSO

       IO::Handle

AUTHOR

       Graham Barr. Currently maintained by the Perl Porters.  Please report all bugs to <perlbug@perl.org>.

COPYRIGHT

       Copyright (c) 1996-8 Graham Barr <gbarr@pobox.com>. All rights reserved.  This program is free software; you can redistribute it and/or
       modify it under the same terms as Perl itself.

perl v5.18.2							    2013-11-04							     IO::Pipe(3pm)