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  • How to show percentage of 'memory used' in a win32 process?

    - by pj4533
    I know that memory usage is a very complex issue on Windows. I am trying to write a UI control for a large application that shows a 'percentage of memory used' number, in order to give the user an indication that it may be time to clear up some memory, or more likely restart the application. One implementation used ullAvailVirtual from MEMORYSTATUSEX as a base, then used HeapWalk() to walk the process heap looking for additional free memory. The HeapWalk() step was needed because we noticed that after a while of running the memory allocated and freed by the heap was never returned and reported by the ullAvailVirtual number. After hours of intensive working, the ullAvailVirtual number no longer would accurately report the amount of memory available. However, this method proved not ideal, due to occasional odd errors that HeapWalk() would return, even when the process heap was not corrupted. Further, since this is a UI control, the heap walking code was executing every 5-10 seconds. I tried contacting Microsoft about why HeapWalk() was failing, escalated a case via MSDN, but never got an answer other than "you probably shouldn't do that". So, as a second implementation, I used PagefileUsage from PROCESS_MEMORY_COUNTERS as a base. Then I used VirtualQueryEx to walk the virtual address space adding up all regions that weren't MEM_FREE and returned a value for GetMappedFileNameA(). My thinking was that the PageFileUsage was essentially 'private bytes' so if I added to that value the total size of the DLLs my process was using, it would be a good approximation of the amount of memory my process was using. This second method seems to (sorta) work, at least it doesn't cause crashes like the heap walker method. However, when both methods are enabled, the values are not the same. So one of the methods is wrong. So, StackOverflow world...how would you implement this? which method is more promising, or do you have a third, better method? should I go back to the original method, and further debug the odd errors? should I stay away from walking the heap every 5-10 seconds? Keep in mind the whole point is to indicate to the user that it is getting 'dangerous', and they should either free up memory or restart the application. Perhaps a 'percentage used' isn't the best solution to this problem? What is? Another idea I had was a color based system (red, yellow, green, which I could base on more factors than just a single number)

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  • Questions on about TDD or unit testing in ASP.NET MVC

    - by Diego
    I've been searching on how to do Unit testing and find thats is quite easy, but, what I want to know is, In a asp.net mvc application, what should be REALLY important to test and which methods you guys use? I just can't find a clear answer on about WHAT TO REALLY TEST when programming unit tests. I just don't want to make unecessary tests and loose developement time doing overkill tests.

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  • c++ class member functions selected by traits

    - by Jive Dadson
    I am reluctant to say I can't figure this out, but I can't figure this out. I've googled and searched stackoverflow, and come up empty. The abstract, and possibly overly vague form of the question is, how can I use the traits-pattern to instantiate non-virtual member functions? The question came up while modernizing a set of multivariate function optimizers that I wrote more than 10 years ago. The optimizers all operate by selecting a straight-line path through the parameter space away from the current best point (the "update"), then finding a better point on that line (the "line search"), then testing for the "done" condition, and if not done, iterating. There are different methods for doing the update, the line-search, and conceivably for the done test, and other things. Mix and match. Different update formulae require different state-variable data. For example, the LMQN update requires a vector, and the BFGS update requires a matrix. If evaluating gradients is cheap, the line-search should do so. If not, it should use function evaluations only. Some methods require more accurate line-searches than others. Those are just some examples. The original version instatiates several of the combinations by means of virtual functions. Some traits are selected by setting mode bits. Yuck. It would be trivial to define the traits with #define's and the member functions with #ifdef's and macros. But that's so twenty years ago. It bugs me that I cannot figure out a whiz-bang modern way. If there were only one trait that varied, I could use the curiously recurring template pattern. But I see no way to extend that to arbitrary combinations of traits. I tried doing it using boost::enable_if, etc.. The specialized state info was easy. I managed to get the functions done, but only by resorting to non-friend external functions that have the this-pointer as a parameter. I never even figured out how to make the functions friends, much less member functions. Perhaps tag-dispatch is the key. I haven't gotten very deeply into that. Surely it's possible, right? If so, what is best practice?

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  • is this possible in java or any other programming language

    - by drake
    public abstract class Master { public void printForAllMethodsInSubClass() { System.out.println ("Printing before subclass method executes"); } } public class Owner extends Master { public void printSomething () { System.out.println ("This printed from Owner"); } public int returnSomeCals () { return 5+5; } } Without messing with methods of subclass...is it possible to execute printForAllMethodsInSubClass() before the method of a subclass gets executed?

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  • How to provide KeyPress event to WebBrowser control?

    - by Pritorian
    Hi all, i really need to catch "ESC" key press while focus is on WebBrowser control. I tried something like this: (webControl as Control).KeyPress += new KeyPressEventHandler(MyKeyPressEventHandler); But it doesnt work. The method is not called. I tried some methods, described here, but dont get any result ( Help, please.

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  • HTTP GET: Same GET-Parameter multiple Times, is this allowed by RFCs?

    - by bernhard
    Hello, are all "Standard Compliant (HTTP RFC?)" Web-Servers forced to "somehow" provide some methods to get all Parameters with the same name as some kind of list/array? Or will will using the same parameter name lead to overwriting: Example: http://www.stackoverflow?myparam=value1&myparam=value2 Will this lead to myparam holding the values "value1,value2" or only "value2" (due to overwriting and only using the last one). Is this behaviour mandated by some standard? thanks bernhard

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  • How can I merge properties of two JavaScript objects dynamically?

    - by JC Grubbs
    I need to be able to merge two (very simple) JavaScript objects at runtime. For example I'd like to: var obj1 = { food: 'pizza', car: 'ford' } var obj2 = { animal: 'dog' } obj1.merge(obj2); //obj1 now has three properties: food, car, and animal Does anyone have a script for this or know of a built in way to do this? I do not need recursion, and I do not need to merge functions, just methods on flat objects.

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  • Are you human? (or How to prevent spam)

    - by pek
    What mechanisms do you know that prevent your site from being abused by anonymous spammers. For example, let's say that I have a site where people can vote something. But I don't want someone to spam something all the way to the top. So I found (a) creating an account and only allowed to vote once and (b) CAPTCHA to decrease spam. What other methods do you know and how good do they work?

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  • Dynamically calculate frequency value.

    - by MS Nathan
    Hi, In my app, I want to find/calculate the audio frequency as dynamically when i am recording an audio and no need to save, play and all. Now i am trying to do that with help of an aurioToch sample code. In that sample, inside FFTBufferManager class methods such as GrabAudioData and ComputeFFT,Here I am not able to find where they are calculating frequency value as dynamically depends on the audio sound and I spent more than 5 days.please help me.

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  • How should I avoid memoization causing bugs in Ruby?

    - by Andrew Grimm
    Is there a consensus on how to avoid memoization causing bugs due to mutable state? In this example, a cached result had its state mutated, and therefore gave the wrong result the second time it was called. class Greeter def initialize @greeting_cache = {} end def expensive_greeting_calculation(formality) case formality when :casual then "Hi" when :formal then "Hello" end end def greeting(formality) unless @greeting_cache.has_key?(formality) @greeting_cache[formality] = expensive_greeting_calculation(formality) end @greeting_cache[formality] end end def memoization_mutator greeter = Greeter.new first_person = "Bob" # Mildly contrived in this case, # but you could encounter this in more complex scenarios puts(greeter.greeting(:casual) << " " << first_person) # => Hi Bob second_person = "Sue" puts(greeter.greeting(:casual) << " " << second_person) # => Hi Bob Sue end memoization_mutator Approaches I can see to avoid this are: greeting could return a dup or clone of @greeting_cache[formality] greeting could freeze the result of @greeting_cache[formality]. That'd cause an exception to be raised when memoization_mutator appends strings to it. Check all code that uses the result of greeting to ensure none of it does any mutating of the string. Is there a consensus on the best approach? Is the only disadvantage of doing (1) or (2) decreased performance? (I also suspect freezing an object may not work fully if it has references to other objects) Side note: this problem doesn't affect the main application of memoization: as Fixnums are immutable, calculating Fibonacci sequences doesn't have problems with mutable state. :)

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  • Animations and MVVM in Silverlight

    - by user275561
    OK I have looked and searched all i want to do is fire a storyboard animation from my view model onto my view. The problem is there is just simply too much boilerplate code to get a simple thing like myStoryboard.Begin(); firing. So what are the methods that you use? Currently, I am using Silverlight 3, MVVM Light.

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  • Using Session in Silverlight using simple WebServices (NOT WCF)

    - by Syed
    Hi, I need to use Session variables in my Silverlight application ( Using Visual Studio 2008, and Silverlight 3). I am already using a webservice (not WCF service) and would like to know if I can add two methods say GetSessionVariable and SetSessionVariable in my existing WebService Class? Any assistance with sample code would be great! Regards and Thanks in advance, Nadeem.

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  • unistd.h related problem when compiling bison & flex program under vc++

    - by Eric
    I'm using bison & flex (downloaded via cygwin) with vc++. When I compile the program I got an error: ...: fatal error C1083: Cannot open include file: 'unistd.h': No such file or directory The corresponding code in the flex-generated file is: #ifndef YY_NO_UNISTD_H /* Special case for "unistd.h", since it is non-ANSI. We include it way * down here because we want the user's section 1 to have been scanned first. * The user has a chance to override it with an option. */ /* %if-c-only */ #include <unistd.h> /* %endif */ /* %if-c++-only */ /* %endif */ #endif If I define YY_NO_UNISTD_H in the flex file(.l) this error will disappear, but I get several other errors: ...: error C2447: '{' : missing function header (old-style formal list?) ...: warning C4018: '<' : signed/unsigned mismatch ...: error C3861: 'isatty': identifier not found How can I fix this problem? All these errors occur in the flex-generated scanner. I know it's because unistd.h doesn't exist in windows. Do I have to write my own unistd.h? If so how to write it in order to eliminate those errors?

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  • Java map / nio / NFS issue causing a VM fault: "a fault occurred in a recent unsafe memory access op

    - by Matthew Bloch
    I have written a parser class for a particular binary format (nfdump if anyone is interested) which uses java.nio's MappedByteBuffer to read through files of a few GB each. The binary format is just a series of headers and mostly fixed-size binary records, which are fed out to the called by calling nextRecord(), which pushes on the state machine, returning null when it's done. It performs well. It works on a development machine. On my production host, it can run for a few minutes or hours, but always seems to throw "java.lang.InternalError: a fault occurred in a recent unsafe memory access operation in compiled Java code", fingering one of the Map.getInt, getShort methods, i.e. a read operation in the map. The uncontroversial (?) code that sets up the map is this: /** Set up the map from the given filename and position */ protected void open() throws IOException { // Set up buffer, is this all the flexibility we'll need? channel = new FileInputStream(file).getChannel(); MappedByteBuffer map1 = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size()); map1.load(); // we want the whole thing, plus seems to reduce frequency of crashes? map = map1; // assumes the host writing the files is little-endian (x86), ought to be configurable map.order(java.nio.ByteOrder.LITTLE_ENDIAN); map.position(position); } and then I use the various map.get* methods to read shorts, ints, longs and other sequences of bytes, before hitting the end of the file and closing the map. I've never seen the exception thrown on my development host. But the significant point of difference between my production host and development is that on the former, I am reading sequences of these files over NFS (probably 6-8TB eventually, still growing). On my dev machine, I have a smaller selection of these files locally (60GB), but when it blows up on the production host it's usually well before it gets to 60GB of data. Both machines are running java 1.6.0_20-b02, though the production host is running Debian/lenny, the dev host is Ubuntu/karmic. I'm not convinced that will make any difference. Both machines have 16GB RAM, and are running with the same java heap settings. I take the view that if there is a bug in my code, there is enough of a bug in the JVM not to throw me a proper exception! But I think it is just a particular JVM implementation bug due to interactions between NFS and mmap, possibly a recurrence of 6244515 which is officially fixed. I already tried adding in a "load" call to force the MappedByteBuffer to load its contents into RAM - this seemed to delay the error in the one test run I've done, but not prevent it. Or it could be coincidence that was the longest it had gone before crashing! If you've read this far and have done this kind of thing with java.nio before, what would your instinct be? Right now mine is to rewrite it without nio :)

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  • Move from *this in an rvalue method?

    - by FredOverflow
    In C++0x, methods can be overloaded on whether or not the expression that denotes the object on which the method is called is an lvalue or an rvalue. If I return *this from a method called via an rvalue, do I need to explicitly move from *this or not? Foo Foo::method() && { return std::move(*this); // Is this move required or not? } Unfortunately, I can't simply test this on my compiler since g++ does not support this feature yet :(

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  • main vs initialize in Ruby

    - by Dave
    Okay, so I've looked through a couple of my ruby books and done some googling to no avail. What is the difference between main and initialize in Ruby? I've seen code that uses class Blahblah def main some logic here end #more methods... end and then calls it using Blahblah.new. Isn't new reserved only for initialize? if not, then what's the difference between the two?

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  • initWithCoder works, but init seems to be overwriting my objects properties?

    - by Zigrivers
    Hi guys, I've been trying to teach myself how to use the Archiving/Unarchiving methods of NSCoder, but I'm stumped. I have a Singleton class that I have defined with 8 NSInteger properties. I am trying to save this object to disk and then load from disk as needed. I've got the save part down and I have the load part down as well (according to NSLogs), but after my "initWithCoder:" method loads the object's properties appropriately, the "init" method runs and resets my object's properties back to zero. I'm probably missing something basic here, but would appreciate any help! My class methods for the Singleton class: + (Actor *)shareActorState { static Actor *actorState; @synchronized(self) { if (!actorState) { actorState = [[Actor alloc] init]; } } return actorState; } -(id)init { if (self = [super init]) { NSLog(@"New Init for Actor started...\nStrength: %d", self.strength); } return self; } -(id)initWithCoder:(NSCoder *)coder { if (self = [super init]) { strength = [coder decodeIntegerForKey:@"strength"]; dexterity = [coder decodeIntegerForKey:@"dexterity"]; stamina = [coder decodeIntegerForKey:@"stamina"]; will = [coder decodeIntegerForKey:@"will"]; intelligence = [coder decodeIntegerForKey:@"intelligence"]; agility = [coder decodeIntegerForKey:@"agility"]; aura = [coder decodeIntegerForKey:@"aura"]; eyesight = [coder decodeIntegerForKey:@"eyesight"]; NSLog(@"InitWithCoder executed....\nStrength: %d\nDexterity: %d", self.strength, self.dexterity); [self retain]; } return self; } -(void) encodeWithCoder:(NSCoder *)encoder { [encoder encodeInteger:strength forKey:@"strength"]; [encoder encodeInteger:dexterity forKey:@"dexterity"]; [encoder encodeInteger:stamina forKey:@"stamina"]; [encoder encodeInteger:will forKey:@"will"]; [encoder encodeInteger:intelligence forKey:@"intelligence"]; [encoder encodeInteger:agility forKey:@"agility"]; [encoder encodeInteger:aura forKey:@"aura"]; [encoder encodeInteger:eyesight forKey:@"eyesight"]; NSLog(@"encodeWithCoder executed...."); } -(void)dealloc { //My dealloc stuff goes here [super dealloc]; } I'm a noob when it comes to this stuff and have been trying to teach myself for the last month, so forgive anything obvious. Thanks for the help!

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  • Method Vs Property

    - by obsoleteattribute
    Hi, I'm a newbie to .NET. I have a class called Project, a project can have multiple forecasts.Now If I want to check if the projects has any forecasts or not should I use a readonly boolean property called HasForecast() or should I use a method named HasForecast() which basically returns a boolean value.From framework design guidelines I came to know that methods should be used when the operation is complex,since here I'm retrieving the value of forecasts from DB should I consider method, or since it is a logical data member should I use a property.If I use a property can I call a method in DBLayer from its getter.Please explain Regards, Ravi

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