sub FETCH {
my ($self, $errname) = @_;
my $proto = prototype("Errno::$errname");
+ my $errno = "";
if (defined($proto) && $proto eq "") {
no strict 'refs';
- return $! == &$errname;
+ $errno = &$errname;
+ $errno = 0 unless $! == $errno;
}
- return "";
+ return $errno;
}
sub STORE {
}
sub FIRSTKEY {
- my $s = scalar keys %Errno::;
+ my $s = scalar keys %Errno::; # initialize iterator
goto &NEXTKEY;
}
tag, C<:POSIX>, which will export all POSIX defined error numbers.
C<Errno> also makes C<%!> magic such that each element of C<%!> has a
-non-zero value only if C<$!> is set to that value, eg
+non-zero value only if C<$!> is set to that value. For example:
use Errno;
-
+
unless (open(FH, "/fangorn/spouse")) {
if ($!{ENOENT}) {
warn "Get a wife!\n";
}
}
-If a specified constant C<EFOO> doesn't exist on the system, C<$!{EFOO}>
-has a false value. You may use C<exists $!{EFOO}> to check whether the
+If a specified constant C<EFOO> does not exist on the system, C<$!{EFOO}>
+returns C<"">. You may use C<exists $!{EFOO}> to check whether the
constant is available on the system.
+=head1 CAVEATS
+
+Importing a particular constant may not be very portable, because the
+import will fail on platforms that do not have that constant. A more
+portable way to set C<$!> to a valid value is to use:
+
+ if (exists &Errno::EFOO) {
+ $! = &Errno::EFOO;
+ }
+
=head1 AUTHOR
Graham Barr <gbarr@pobox.com>