Errno

use Errno; unless (open(FH, $pathname)) {
 if ($!{ENOENT}) {
 # We don't need an import for this! warn "$pathname does not exist\n";
}
else {
 warn "open failed on `$pathname': $!";
}
} use Errno qw(EINTR EIO :POSIX); if ($! == ENOENT) {
 .... }

The Errno module makes available the symbolic names for the error status values set when a syscall fails, but does not export them by default. The module has a single export tag, ":POSIX", which exports only those symbols defined by the POSIX 1003.1 standard. The module also makes the global %! variable magical using tie. You can subscript into the %! hash using any valid errno on your system, not just the POSIX ones, and its value is true only if that's the current error.