Errno (3)
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NAME
Errno - System errno constantsSYNOPSIS
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 allPOSIX
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 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;
}