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

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.

       On Windows, "Errno" also	defines	and conditionally exports all the
       Winsock error constants defined in your system WinError.h include file.
       These are included in a second export tag, ":WINSOCK".

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

	   my $fh;
	   unless (open($fh, "<", "/fangorn/spouse")) {
	       if ($!{ENOENT}) {
		   warn	"Get a wife!\n";
	       } 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.

       Perl automatically loads	"Errno"	the first time you use "%!", so	you
       don't need an explicit "use".

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 v5.26.0			  2017-07-03			      Errno(3)

NAME | SYNOPSIS | DESCRIPTION | CAVEATS | AUTHOR | COPYRIGHT

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