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• How to get at TCP RTT on Windows (Linux TCP_INFO) as an user

  - by FredAlkin

  I am porting a streaming TCP app from Linux to Windows. The app streams real-time audio data using a preexisting TCP protocol (so switching to UDP isn't an option). Further, I wish to avoid being "part of the problem" and requiring Administrator rights. The Linux code uses getsockopt(... ,SOL_TCP, TCP_INFO, ..) to get the RTT (round trip time) information from the TCP connection. The application level uses this to throttle the amount of data sent over the connection (apparently to balance quality with latency). Is there an equivalent to TCP_INFO on WIndows? (google tells me that Win2K and later supports "TCP Timestamps" which would provide this information, but I've yet to find a way to get at it. Thanks in advance.

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• iPhone view architecture question

  - by Joe

  So I have (for instance) three views: A: root view B: a view functionally identical to root C: a data entry view which collects a few piece of info What I'm trying to do is reuse C to supply the data it collects to either A or B. It should supply the data to whichever of the two it is pushed onto. The data for A is similar, but functionally distinct, to what collects for B. Right now, I'm passing data from C to A or B via a singleton class. What I'm trying to avoid is having two instances of C, one to supply data to A and B (because, in actuality, the program will have 5 total views like C. Does the question make sense?

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• How to address thread-safety of service data used for maintaining static local variables in C++?

  - by sharptooth

  Consider the following scenario. We have a C++ function with a static local variable: void function() { static int variable = obtain(); //blahblablah } the function needs to be called from multiple threads concurrently, so we add a critical section to avoid concurrent access to the static local: void functionThreadSafe() { CriticalSectionLockClass lock( criticalSection ); static int variable = obtain(); //blahblablah } but will this be enough? I mean there's some magic that makes the variable being initialized no more than once. So there's some service data maintained by the runtime that indicates whether each static local has already been initialized. Will the critical section in the above code protect that service data as well? Is any extra protection required for this scenario?

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• exactly what does rake db:migrate do?

  - by happythenewsad

  Does rake db:migrate only add new migrations, or does it drop all migrations/changes and build everything new? I think rake is throwing an error because it is trying to access a table attribute in migration 040 that was deleted in migration 042. somehow my DB and rake are out of synch and I want to fix them. for you experts out there - is it common for rake to get out of synch with migrations? how can I avoid this (no, I do not hand-edit my schema or rake files).

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• Override decimal ToString() method

  - by Jimbo

  I have a decimal datatype with a precision of (18, 8) in my database and even if its value is simply 14.765 it will still get displayed as 14.76500000 when I use Response.Write to return its value into a webpage. Is it possible to override its default ToString method to return the number in the format #,###,##0.######## so that it only displays relevant decimal places? UPDATE I'm assuming that when one outputs number on a page like <%= item.price %> (where item.price is a number) that the number's ToString method is being called? I'm trying to avoid having to change every instance where the value is displayed by defaulting the ToString() format somehow.

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• Submit multiple forms as one

  - by Stephen Sarcsam Kamenar

  I have two forms on the page. To the user it looks like 1 form, and I actually wish it was one form. But the way I'm trying to reuse code and include things, I can't avoid two forms in the source code... trying to act as one. I don't want to do ajax submit, I want a normal post submit, my form handler has redirects in it. How can I submit both of these, and get values that make sense on the server side. something like $_POST['form1]['whatever'] $_POST['form2]['thing'] Maybe take all the inputs from form 2, rename all of them with a prefix, and append them to form 1? I can't find a non-messy way of doing this. I don't think I need code, just a plan. Least messy idea wins.

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• Thread Suicide on Shutdown?

  - by yar

  I have a java.util.Timer running at a fixed interval. I have added a Runtime#addShutdownHook and it shuts down when the VM ends normally or abnormally. However, it keeps the VM alive when a main terminates, unless I insist by doing a System.exit in the main. Is there any way for me to check if I'm the last Thread standing, or some other way to avoid altering a main that would exit normally on finish? Note: I know a lot of people believe that java.util.Timer is deprecated (it's not), but unless your alternative helps me solve this problem...

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• maintain formatting entered into an html form?

  - by NickG77

  Im setting up a web form, and I'm trying to have it where visitors can paste their resumes into a text area. Then I want to email the info using php mail(). But the resume info is just stored in the variable as one long string with no formatting. Is there a way I can send the pasted resume text to the client in the resume format? Maintaining all the line breaks and stuff? He wants to avoid having people upload resumes.

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• Best way of obfuscating / encrypting form data on the iPhone

  - by cannyboy

  I want to create an app which holds sensitive information (imagine it's bank account details, thought it's not). The user enters this information on a form the first time the app starts up. I want this info to be saved, and available, any time the user uses the app (without having to enter a password). However, if the iPhone has a password lock on it, and is stolen, I don't want the data to be easily accessible from the file system. What is the best way of encrypting or obfuscating the data? There is not a lot of data, just a dozen NSStrings from the UITextFields on the form. I'm aware there are encryption export restrictions on the iPhone for non-US developers (I am in UK), so I would prefer to avoid going jumping through any of Apple's app submission hoops to get it on the store.

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• How do I automatically reset a boolean when any method other is called in C#?

  - by gtaborga

  Hey everyone, Using C#, I need to do some extra work if function A() was called right before function C(). If any other function was called in between A() and C() then I don't want to do that extra work. Any ideas that would require the least amount of code duplication? I'm trying to avoid adding lines like "flag = false;" into every function B1..BN. Here is a very basic example: bool flag = false; void A() { flag = true; } void B1() { ... } void B2() { ... } void C() { if (flag) { //do something } } The above example was just using a simple case but I'm open to using something other than booleans. The important thing is that I want to be able to set and reset a flag of sorts so that C() knows how to behave accordingly. Thank you for your help. If you require clarification I will edit my post.

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• Can I reproduce Scala's behavior for == ?

  - by JPP

  In Programming in Scala, I can read that the == operator behaves as if it was defined like this: final def == (that: Any): Boolean = if (null eq this) {null eq that} else {this equals that} But there must actually be compiler magic to avoid null pointer exceptions, right? Is there any way for me to replicate this behavior with pure Scala; i.e., have an operator/method return one thing if the receiver is null and another one if it isn't? What I mean is an actual implementation of null eq this. I suppose I can write a "pimp" and then define the method on the wrapper class, but is there a more direct way to do this?

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• How do you send an array as part of an (jquery) ajax request

  - by Ankur

  I tried to send an array as part of an ajax request like this: var query = []; // in between I add some values to 'query' $.ajax({ url: "MyServlet", data: query, dataType: "json", success: function(noOfResults) { alert(noOfResults); } }); } I wanted to see what I get back in the servlet, so I used this line: System.out.println(request.getParameterMap().toString()); Which returned {} suggesting an empty map. Firebug tells me I am getting a 400 bad request error If I send a queryString like attribute=value as the 'data' then everything works fine, so it has to do with not being able to send an array as is. What do I have to do to get that data into the servlet for further processing. I don't want to pull it out and turn it into a queryString in the JS if I can avoid it. EDIT: I used the .serializeArray() (jQuery) function before sending the data. I don't get the 400 but nothing useful is being sent through.

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• can ping but cannot browse.Can you help

  - by user231465

  Hi all I have winxp with the latest service pack on my old laptop. I have a situation where I can Ping and status says connected but cannot browse. I have seen various post on the net proposing solutions that works for some and not for others I have tried reseting winsock but nothing. If I vpn to my work then I can browse. I would like to avoid reformatting the computer and not take such a drastic action. Any suggestions?

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• strategy to allocate/free lots of small objects

  - by aaa

  hello I am toying with certain caching algorithm, which is challenging somewhat. Basically, it needs to allocate lots of small objects (double arrays, < 256 elements), with objects accessible through mapped value, map[key] = array. time to initialized array may be quite large, generally more than 10 thousand cpu cycles. By lots I mean around gigabyte in total. objects may need to be popped/pushed as needed, generally in random places, one object at a time. lifetime of an object is generally long, minutes or more, however, object may be subject to allocation/deallocation several times during duration of program. What would be good strategy to avoid memory fragmentation, while still maintaining reasonable allocate deallocate speed? I am using C++, so I can use new and malloc. Thanks. I know there a similar questions on website, http://stackoverflow.com/questions/2156745/efficiently-allocating-many-short-lived-small-objects, are somewhat different, thread safety is not immediate issue for me.

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• this pointer to base class constructor?

  - by Rolle

  I want to implement a derived class that should also implement an interface, that have a function that the base class can call. The following gives a warning as it is not safe to pass a this pointer to the base class constructor: struct IInterface { void FuncToCall() = 0; }; struct Base { Base(IInterface* inter) { m_inter = inter; } void SomeFunc() { inter->FuncToCall(); } IInterface* m_inter; }; struct Derived : Base, IInterface { Derived() : Base(this) {} FuncToCall() {} }; What is the best way around this? I need to supply the interface as an argument to the base constructor, as it is not always the dervied class that is the interface; sometimes it may be a totally different class. I could add a function to the base class, SetInterface(IInterface* inter), but I would like to avoid that.

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• facelet - nested <ui:insert>

  - by user321350

  I have multiple templates which differs with each other only by few containers. The most complex one contains superset of all containers used in all other one thus to avoid creating multiple templates I created the most complex one in following format some layout stuff (div and all) defining nested insert for each container and content. Now in client template based on what is needed I turn off container which is not needed as else if container is needed, just define content as doSomething Please let me know if you guys see any issues with this approach, any potential problem or alternate approach for similar scenario. thanks a lot. Maddy

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• How to manage member variable in C++

  - by rhapsodyn

  In brief, my question is about member variables as pointers in unmanaged C++. In java or c#, we have "advanced pointer". In fact, we can't aware the "pointer" in them. We usually initialize the member of a class like this: member = new Member(); or member = null; But in c++, it becomes more confusing. I have seen many styles: using new, or leave the member variable in stack. In my point of view, using boost::shared_ptr seems friendly, but in boost itself source code there are news everywhere. It's the matter of efficiency,isn't it? Is there a guildline like "try your best to avoid new" or something?

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• I18n translation problem

  - by kshchepelin

  I'm about to translate all time zones to Russian and I've done such things: model: # lib/i18n_time_zone.rb class I18nTimeZone < ActiveSupport::TimeZone def self.all super.map { |z| create(z.name, z.utc_offset) } end def to_s translated_name = I18n.t(name, :scope => :timezones, :default => name) "(GMT#{formatted_offset}) #{translated_name}" end end view: <%= time_zone_select :user, :time_zone, nil, :model => I18nTimeZone %> locale file (/config/locales/ru.yml): ru: timezones: "Midway Island": "??????" "Samoa": "?????" .... But there are cases when original string includes some dots (".") Like "St. Petersburg" And I18n.t() tells me that translation is missing. How can I avoid it?

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• formatting european characters from JSON results

  - by mlecho

  hi, i am building an application that imports JSON results and parses the objects to a table cell. Nothing fancy, but in my results, many of the terms/names are European with characters such as è or ú which come out as \u00E9 or \u00FA. I think these are ASCII ? or unicode? ( i can never keep em staight). Anyway, like all good NSSTring's, i figured there must be a method to fix this, but i am not finding it....any ideas? I am trying to avoid doing something like this: this posting. Thanks all.

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• How to define an array inside a function in C?

  - by Arunav Dev

  So in my source file I have the folowin function: void update(state* old_state, state* measurement, uint32_t size) { state new_state[size]; //some function using measurement and old_state and returning the result in newstate arm_fadd_32(measurement,old_state,newstate,size); // rest of the code } Now the compiler throws an error saying that error#28:expression must have a constant value. I think it's due to the fact that even though inside the method the size local variable is not changing the compiler is expecting a constant while defining the size. I have tried the following: int const a = size; and then tried to reinitialize it says constant value is not known. I did some research in internet and it appears that there is no easier way without using malloc, which I don't want to since I am using the code for some embedded application. Is there a way to avoid this problem without really using malloc? Thanks in advance guys!

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• Header files in C++

  - by user269037

  Hi, I am making a simulator and have written lots of files and headers. The problem is whenever I include a file I give the relative path of the particular file. For example a typical code in my application would begin like ifndef AI_H define AI_H include include "../world/world.h" include "pathPlan.h" include "skills/tryskill.h" include "../info/condition.h" include "dataStructures/destination.h" include "../params/gamePlay.h" include "../modules/controlModule.h" class ai { public: etc etc I want to avoid using the relative paths. For example I want to directly include "tryskill.h" and "destination.h" without giving the absolute paths. That way I wont need to bother if I change the location of any particular file. I am using Ubuntu 9.10. Any help would be highly appreciated.

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• Is there a way to test if a scalar has been stringified or not?

  - by Yobert

  I am writing a thing to output something similar to JSON, from a perl structure. I want the quoting to behave like this: "string" outputs "string" "05" outputs "05" "5" outputs "5" 5 outputs 5 05 outputs 5, or 05 would be acceptable JSON::XS handles this by testing if a scalar has been "stringified" or not, which I think is very cool. But I can't find a way to do this test myself without writing XS, which I'd rather avoid. Is this possible? I can't find this anywhere on CPAN without finding vast pedantry about Scalar::Util::looks_like_number, etc which completely isn't what I want. The only stopgap I can find is Devel::Peek, which feels evil. And also, just like JSON::XS, I'm fine with this secenario: my $a = 5; print $a."\n"; # now $a outputs "5" instead of 5)

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• Aptana Open Resource Key Binding

  - by yagudaev

  The default keyboard shortcut for open resource in Eclipse is Ctrl+Shift+R. It is also the case in Aptana, but there also seems to be a conflicting key since when clicked it brings up a context menu with 2 options "Run" and "Open Resource". How to I avoid having this context menu pop up? I tried to go to the preferences and look for conflicting key-bindings but I could not find it. I am also not sure what "Run" command is actually bound (I tried searching based on the key combination, that did not seem to have worked).

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• Querying Postgresql with a very large result set

  - by sanity

  In an application I need to query a Postgres DB where I expect tens or even hundreds of millions of rows in the result set. I might do this query once a day, or even more frequently. The query itself is relatively simple, although may involve a few JOINs. My question is: How smart is Postgres with respect to avoiding having to seek around the disk for each row of the result set? Given the time required for a hard disk seek, this could be extremely expensive. If this isn't an issue, how does Postgres avoid it? How does it know how to lay out data on the disk such that it can be streamed out in an efficient manner in response to this query?

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• Does jquery require timestamp on GET Calls in IE7?

  - by Mithun P

  Please see the jQuery code below, it used to paginate some search results paginate: function() { $("#wishlistPage .results").html("<div id='snakeSpinner'><img src='"+BASE_URL+"images/snake.gif' title='Loading' alt='...'/></div>"); var url = BASE_URL+"wishlist/wishlist_paginated/"; $.ajax({ type: "GET", url: url, data: { sort_by:$('#componentSortOrder input:hidden').val(), offset:My.WishList.offset, per_page: 10, timestamp: new Date().getTime() }, success: function(transport){ $("#wishlistPage .results").html(transport); } }); }, My issue is not with the pagination, issue is when i need to call this same function when something happed to other part of the page which remove some search results, it brings the old results in IE7, other browsers works fine. So added the timestamp: new Date().getTime() part. That fixed the IE issue. I want o know why this happens in jQuery? Do I need to include a timestamp parameter to URL to avoid caching in all jQuery Ajax calls?

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