When a connection is in asynchronous mode, failing operations (search,

	scan, etc.) no longer throw exceptions.  This is because the
	event-loop in asychronous applications needs to check for
	errors anyway, in case the server has returned high-level
	diagnostics such as "unsupported use attribute".  So this
	check within the event-loop is now the only place where
	error-checking need be done.
Add new public ZOOM::Connection() function, check(), which throws an
	exception if an error is pending (even if the connection is
	asynchronous).
New YAZ logging level, "zoom_check", notes when errors are detected
	and either left unreported (asynchronous connections) or
	thrown as exception (synchronous).

diff --git a/lib/ZOOM.pm b/lib/ZOOM.pm
index e99ddc7..a571872 100644 (file)
--- a/lib/ZOOM.pm
+++ b/lib/ZOOM.pm
@@ -1,4 +1,4 @@
-# $Id: ZOOM.pm,v 1.45 2007-02-13 15:31:26 mike Exp $
+# $Id: ZOOM.pm,v 1.46 2007-02-26 14:36:55 mike Exp $
 
 use strict;
 use warnings;
@@ -337,20 +337,34 @@ sub _conn {
 
 sub _check {
     my $this = shift();
+    my($always_die_on_error) = @_;
 
     my($errcode, $errmsg, $addinfo, $diagset) = (undef, "x", "x", "x");
     $errcode = Net::Z3950::ZOOM::connection_error_x($this->_conn(), $errmsg,
                                                    $addinfo, $diagset);
     if ($errcode) {
-       if ($this->option("_check_debug")) {
-           print STDERR "ZOOM WARNING!  $this->check() failed with error $diagset:$errcode ($errmsg) $addinfo\n";
-           print STDERR "SIG{SEGV} ", (defined $SIG{SEGV} ? ("= '" . $SIG{SEGV} . "'") : "undefined"), "'\n";
-           print STDERR "SIG{__DIE__} ", (defined $SIG{__DIE__} ? ("= '" . $SIG{__DIE__} , "'") : "undefined"), "'\n";
+       my $exception = new ZOOM::Exception($errcode, $errmsg, $addinfo,
+                                           $diagset);
+       if (!$this->option("async") || $always_die_on_error) {
+           ZOOM::Log::log("zoom_check", "throwing error $exception");
+           die $exception;
+       } else {
+           ZOOM::Log::log("zoom_check", "not reporting error $exception");
        }
-       die new ZOOM::Exception($errcode, $errmsg, $addinfo, $diagset);
     }
 }
 
+# This wrapper for _check() is called only from outside the ZOOM
+# module, and therefore only in situations where an asynchronous
+# application is actively asking for an exception to be thrown if an
+# error has been detected.  So it passed always_die_on_error=1 to the
+# underlying _check() method.
+#
+sub check {
+    my $this = shift();
+    return $this->_check(1);
+}
+
 sub create {
     my $class = shift();
     my(@options) = @_;