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!\n";
               } else {
                   warn "This path is barred: $!";
               }
           }

       If a specified constant `EFOO' does not exist on the sys­
       tem, `$!{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.


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