Olivier Langlois's blog - Last commentshttp://blog.olivierlanglois.net/index.php?tempskin=_atom&disp=commentsb2evolution2024-03-19T10:16:09ZIn response to: Optimizing C++ code for Intel processors (and possibly many others)Maurizio [Visitor]http://blog.olivierlanglois.net/index.php/2007/11/25/optimizing_c_code_for_intel_processors_a#c44592012-08-15T03:02:02Z2012-08-15T03:02:02Z
{
delete ptr;
ptr = NULL;
}
should be changed to:
delete ptr;
ptr = NULL;
This is plainly wrong when talking optimizations as the "delete ptr" statement will most likely turn into a function call to the delete operator, which will at the bare minimum check that ptr is not null before looking into the memory heap data structures.]]>In response to: Linksys Wireless-N Gaming Router WRT330N model reviewRMP [Visitor]http://blog.olivierlanglois.net/index.php/2010/12/05/linksys_wireless_n_gaming_router_wrt330n#c10422011-09-02T06:18:40Z2011-09-02T06:18:40ZIn response to: Distributed Systems: Concepts and Design (4th Edition)marwan ahmed abdelhady [Visitor]http://blog.olivierlanglois.net/index.php/2010/03/28/distributed_systems_concepts_and_design_#c8632011-05-24T22:55:39Z2011-05-24T22:55:39ZIn response to: Compiler Design in CTurbo Pascal Fan [Visitor]http://turbopascal.org/http://blog.olivierlanglois.net/index.php/2007/06/02/compiler_design_in_c#c8562011-05-17T14:01:19Z2011-05-17T14:01:19Z
http://turbopascal.org/]]>In response to: NAT traversal for the dummies and the best NAT router for online gaminglano1106 [Member]http://blog.olivierlanglois.net/index.php/2007/05/23/nat_traversal_for_the_dummies_and_the_be#c7142011-03-21T06:49:52Z2011-03-21T06:49:52Z
http://blog.olivierlanglois.net/index.php/2010/12/05/linksys_wireless_n_gaming_router_wrt330n
IMO, Netgear products are of higher quality.
]]>In response to: NAT traversal for the dummies and the best NAT router for online gamingXBox Repair Chicago [Visitor]http://www.xboxrepairchicago.nethttp://blog.olivierlanglois.net/index.php/2007/05/23/nat_traversal_for_the_dummies_and_the_be#c7132011-03-21T01:21:51Z2011-03-21T01:21:51ZIn response to: NAT traversal for the dummies and the best NAT router for online gamingEducational Games Online [Visitor]http://www.funeducationalgamesonline.comhttp://blog.olivierlanglois.net/index.php/2007/05/23/nat_traversal_for_the_dummies_and_the_be#c6762011-02-15T14:32:39Z2011-02-15T14:32:39ZIn response to: Graph breadth-first traversal algorithm C++ implementationstephen [Visitor]http://blog.olivierlanglois.net/index.php/2010/08/24/graph_breadth_first_traversal_algorithm_#c3962010-10-12T06:10:58Z2010-10-12T06:10:58Z
]]>In response to: Graph breadth-first traversal algorithm C++ implementationlano1106 [Member]http://blog.olivierlanglois.net/index.php/2010/08/24/graph_breadth_first_traversal_algorithm_#c3942010-10-11T19:18:17Z2010-10-11T19:18:17Z
You have about 30 minutes, maybe less than that to produce the program. That being said, I am not even sure that I had a working program during the alloted time. and no, they do not pay you for your time like any interviews in any company that I know and IMO, this is the right thing to do.
I have considerably embellished the program once I decided that I would publish it on my website. With all the comments, and all the cool STL usages within the program, I would say that I spent a good evening to bring the program as it is now.
]]>In response to: Graph breadth-first traversal algorithm C++ implementationStephen Reis [Visitor]http://www.terminalserverprinting.org/http://blog.olivierlanglois.net/index.php/2010/08/24/graph_breadth_first_traversal_algorithm_#c3932010-10-11T15:01:52Z2010-10-11T15:01:52ZIn response to: Logitech Quickcam Fusionendorphin [Visitor]http://blog.olivierlanglois.net/index.php/2007/10/30/logitech_quickcam_fusion#c2492010-04-03T17:28:47Z2010-04-03T17:28:47Z
Now, trying fix this not welcome problem]]>In response to: TCP RST flag subtletiesJoe Beckner [Visitor]http://www.UniplexNetworks.comhttp://blog.olivierlanglois.net/index.php/2010/02/06/tcp_rst_flag_subtleties#c2462010-03-26T12:42:29Z2010-03-26T12:42:29ZIn response to: TCP RST flag subtletieslano1106 [Member]http://blog.olivierlanglois.net/index.php/2010/02/06/tcp_rst_flag_subtleties#c2442010-03-26T10:47:39Z2010-03-26T10:47:39Z
it seems to be different. In the scenario I am describing, the client TCP/IP stack do receive the server reply. It is the application that do not sees it because a RST is immediately following the reply and is received by the TCP/IP stack before the application has the chance to read the reply from the stack.
This is not the problem that you have because if it was, you would see the reply precedes the RST segment with Wireshark.
In your situation, if you were asking me my opinion, I would suspect your router to be a NAT device and gmail server must have an internal limit that makes it refuse a single IP address to initiate more than a certain number of connections to protect itself against spammers.
I see some avenues to solve the problem:
1. If possible, configure your router to have more than 1 public IP address on the external NIC and make the router NAT module load balance the connections among the available public IP addresses.
2. Here is what my DNS server returns me for gmail.com:
You could tweek your DNS server to let it do the load balance for your users.
Please report back here if this has helped you to fix the problem.
]]>In response to: TCP RST flag subtletiesJoe Beckner [Visitor]http://www.UniplexNetworks.comhttp://blog.olivierlanglois.net/index.php/2010/02/06/tcp_rst_flag_subtleties#c2432010-03-26T09:59:42Z2010-03-26T09:59:42Z
I should preface my comment by stating that I am not a software programmer, I am a network hardware person who sells, install and maintains Cisco network switches, routers and firewalls for small and medium businesses.
I am troubleshooting an intermittent problem for a client who has about 100 users on gmail. They experiencing intermittent periods where one or more users cannot access their gmail. All other internet traffic (web, etc.)is ok. Resetting the Cisco3825 router firewall on the T1 line clears the problem. I did not believe that this was really a router problem. All sessions are terminated when the router restarts which is probably why it clears.
I have some Wireshark captures from when users are experiencing problems. What I am seeing is an immediate TCP RST coming back from the Google gmail server after the successfull TCP 3 way session initiation for HTTPS. There are no HTTP codes coming back from the server. This repeats over and over.]]>In response to: What is the C++ SFINAE principle ?lano1106 [Member]http://blog.olivierlanglois.net/index.php/2007/09/01/what_is_the_c_sfinae_principle#c2122009-08-31T20:22:24Z2009-08-31T20:22:24Z
To be honest, I had an intellectual understanding of the example I was giving but I have
never bothered to compile it to see if it works until today.
I have tried to compile it with gcc 3.4.4 and I get the same error message. I will try to
find an answer and post it if possible.
Thank you for the comment.
]]>In response to: What is the C++ SFINAE principle ?Michal [Visitor]http://blog.olivierlanglois.net/index.php/2007/09/01/what_is_the_c_sfinae_principle#c2112009-08-31T01:29:18Z2009-08-31T01:29:18Z
Thank You for Your example.
So far I am trying to understand how it works.
Unfortunatelly I have problem with preliminary step: it does not compile on my linux box (g++ (GCC) 4.3.0 20080428 (Red Hat 4.3.0-8)).
I get the following error:
p41.cpp:12: error: expected primary-expression before ">" token
(sorry for modifications in line above, but I couldn't put template parameter T in Your page, because they have a format of tag).
have You got idea why doesn't it compile?
best regards
Michal]]>In response to: CLOSE_WAIT vs TIME_WAITAltosAce [Visitor]http://blog.olivierlanglois.net/index.php/2008/06/05/close_wait_vs_time_wait#c2052009-05-14T16:36:21Z2009-05-14T16:36:21ZIn response to: UNIX Network Programming: Networking APIs: Sockets and XTI; Volume 1, Second editionlano1106 [Member]http://blog.olivierlanglois.net/index.php/2008/07/06/unix_network_programming_networking_apis#c1902009-03-12T19:39:48Z2009-03-12T19:39:48Z
]]>In response to: UNIX Network Programming: Networking APIs: Sockets and XTI; Volume 1, Second editiontanixmukherzee [Visitor]http://blog.olivierlanglois.net/index.php/2008/07/06/unix_network_programming_networking_apis#c1892009-03-10T00:44:32Z2009-03-10T00:44:32Z
i dont know why...
i m giving u the code here..plz help me...
the problem is i am having an error like...socket operation on non-socket...
can u help me out...the server program is okay...)]]>In response to: XML Schema - The W3C's Object-Oriented Descriptions for XMLSimon Sprott [Visitor]http://www.liquid-technologies.comhttp://blog.olivierlanglois.net/index.php/2008/08/04/xml_schema_the_w3c_s_object_oriented_des#c1842009-01-06T11:39:03Z2009-01-06T11:39:03Z
Couple this with a good XML Schema Editor like Liquid XML Studio, and you'll learn the basics of the standard in no time.
The split code/diagram view provides the feedback required to quickly learn the effects on the XSD code as the documents structure changes.]]>