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Search found 633 results on 26 pages for 'charles anderson'.

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  • File descriptor limits and default stack sizes

    - by Charles
    Where I work we build and distribute a library and a couple complex programs built on that library. All code is written in C and is available on most 'standard' systems like Windows, Linux, Aix, Solaris, Darwin. I started in the QA department and while running tests recently I have been reminded several times that I need to remember to set the file descriptor limits and default stack sizes higher or bad things will happen. This is particularly the case with Solaris and now Darwin. Now this is very strange to me because I am a believer in 0 required environment fiddling to make a product work. So I am wondering if there are times where this sort of requirement is a necessary evil, or if we are doing something wrong. Edit: Great comments that describe the problem and a little background. However I do not believe I worded the question well enough. Currently, we require customers, and hence, us the testers, to set these limits before running our code. We do not do this programatically. And this is not a situation where they MIGHT run out, under normal load our programs WILL run out and seg fault. So rewording the question, is requiring the customer to change these ulimit values to run our software to be expected on some platforms, ie, Solaris, Aix, or are we as a company making it to difficult for these users to get going? Bounty: I added a bounty to hopefully get a little more information on what other companies are doing to manage these limits. Can you set these pragmatically? Should we? Should our programs even be hitting these limits or could this be a sign that things might be a bit messy under the covers? That is really what I want to know, as a perfectionist a seemingly dirty program really bugs me.

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  • Does unboxing just return a pointer to the value within the boxed object on the heap?

    - by Charles
    I this MSDN Magazine article, the author states (emphasis mine): Note that boxing always creates a new object and copies the unboxed value's bits to the object. On the other hand, unboxing simply returns a pointer to the data within a boxed object: no memory copy occurs. However, it is commonly the case that your code will cause the data pointed to by the unboxed reference to be copied anyway. I'm confused by the sentence I've bolded and the sentence that follows it. From everything else I've read, including this MSDN page, I've never before heard that unboxing just returns a pointer to the value on the heap. I was under the impression that unboxing would result in you having a variable containing a copy of the value on the stack, just as you began with. After all, if my variable contains "a pointer to the value on the heap", then I haven't got a value type, I've got a pointer. Can someone explain what this means? Was the author on crack? (There is at least one other glaring error in the article). And if this is true, what are the cases where "your code will cause the data pointed to by the unboxed reference to be copied anyway"? I just noticed that the article is nearly 10 years old, so maybe this is something that changed very early on in the life of .Net.

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  • How do I forward map a point in OpenCV using mapx & mapy?

    - by Charles
    Ultimately, I'm trying to determine the 3D location of a point I've identified in two cameras (using OpenCV 2.3.1, Windows 7, C++). I'm having trouble locating the 2D point for each camera from its mapx & mapy. I could not find in Bradski & Kaehler's OpenCV book how to do it. PROCESS calibrateCamera for each of the pair stereoCalibrate stereoRectify detect the blob I want to locate in 3D on each camera in 2D initUndistortRectifyMap for each camera Eventually, perspectiveTransform PROBLEM with 5: I have the x and y location of the point in the distorted and unrectified image for each camera(from #4) but I don't know how to get the undistorted and rectified x and y for each camera from the two maps initUndistortRectifyMap creates for each camera. I don't want to remap the whole image since I only want to learn the 3D location of one object for each frame. QUESTION: How do I forward map a point (get the undistorted and rectified x and y) with its two maps? Thanks for any help.

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  • Post Method Not giving Alerts like planned?

    - by Charles
    <form action="" method="post"> <div align="center"><legend>Add a Code</legend> <label for="code"></label> <input type="text" name="code" id="code" maxlength="10" /> <input type='button' onclick= "isAlphanumeric(document.getElementById('code'),'Your Submission Contained Invalid Characters'); isBadPhrase(document.getElementById('code'), 'Please Enter A Correct Friend Code!');" value='Check Field' /> function isAlphanumeric(elem, helperMsg){ var alphaExp = /^[0-9a-zA-Z]+$/; if(elem.value.match(alphaExp)){ return true; }else{ alert(helperMsg); elem.focus(); return false; } } function isBadPhrase(elem,helperMsg){ var badPhrase=/EPW|ESW|\s/; if (elem.value.match(badPhrase)){ alert(helperMsg); elem.focus(); return false; }else{ return true; } } What is wrong here?

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  • Test for external undefined references in Linux

    - by Charles
    Is there a built in linux utility that I can use to test a newly compiled shared library for external undefined references? Gcc seems to be intelligent enough to check for undefined symbols in my own binary, but if the symbol is a reference to another library gcc does not check at link time. Instead I only get the message when I try to link to my new library from another program. It seems a little silly to get undefined reference messages in a library when I am compiling a different project so I want to know if I can do a check on all references internal and external when I build the library not when I link to it. Example error: make -C UnitTests debug make[1]: Entering directory `~/projects/Foo/UnitTests` g++ [ tons of objects ] -L../libbar/bin -lbar -o UnitTests libbar.so: undefined reference to `DoSomethingFromAnotherLibrary` collect2: ld returned 1 exit status make[1]: *** [~/projects/Foo/UnitTests] Error 1

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  • LINQ to objects: Is there

    - by Charles
    I cannot seem to find a way to have LINQ return the value from a specified accessor. I know the name of the accessors for each object, but am unsure if it is possible to pass the requested accessor as a variable or otherwise achieve the desired refactoring. Consider the following code snippet: // "value" is some object with accessors like: format, channels, language row = new List<String> { String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.format).ToArray()), String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.channels).ToArray()), String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.language).ToArray()), // ... } I'd like to refactor this into a method that uses the specified accessor, or perhaps pass a delegate, though I don't see how that could work. string niceRefactor(myObj myObject, string /* or whatever type */ ____ACCESSOR) { return String.Join(innerSeparator, (from item in myObject.Audio orderby item.Key ascending select item.Value.____ACCESSOR).ToArray()); } I have written a decent amount of C#, but am still new to the magic of LINQ. Is this the right approach? How would you refactor this?

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  • htaccess for swf file

    - by Charles Wayne
    Does htaccess works with swf file that accepts variables? I have this swf url... http://subdom.domain.tld/subfolder/live.swf?stream=rtmp://stream.domain.com/application&provider=rtmp&file=streamname&autostart=true I want it to be rewrite as http://subdom.domain.tld/subfolder/assignedname/ So far this is what I written on .htaccess file RewriteEngine On RewriteRule ^kwt/?$ live.swf?stream=rtmp://stream.domain.com/application&provider=rtmp&file=streamname&autostart=true [NC,L] It does seem to rewrite to the swf file because the swf is showing but for some reason the variable is not recognized. It does not auto play even the auto play variable is set to true in the RewriteRule. Is there something wrong with my code or it can't be done in swf file?

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  • Compile error on action for iPhone app: "error:expected ')' before ';' token"

    - by Jamis Charles
    I'm working through the tutorials in the "Beginning iPhone Development" book. I'm on chapter 4 and I'm getting the following compile error on the "if (segment == kShowSegmentIndex)" line: error:expected ')' before ';' token Here's my code: - (IBAction)toggleShowHide:(id)sender{ UISegmentedControl *segmentedControl = (UISegmentedControl *)sender; NSInteger segment = segmentedControl.selectedSegmentIndex; if (segment == kShowSegmentIndex) [switchView setHidden:NO]; else [switchView setHidden:YES]; } I've compared it with the code in the book several times and have retyped it. Sounds like this error is caused by improper brace placement. Any thoughts?

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  • Validating key/certificate pairs with M2Crypto when a certificate chain is needed

    - by Charles Duffy
    M2Crypto.X509.X509 objects have a verify(pkey) method, which provide a means of testing that a given certificate does in fact sign a specified key. This is a good and useful thing -- except that sometimes the certificate I want to verify in this way is invalid without the use of an intermediate certificate, which this API does not appear to allow a way to specify. Is there an alternate means of validating a certificate / private key pair which will work even when the certificate is unable to stand alone?

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  • Common "truisms" needing correction the most

    - by Charles Bretana
    In addition to "I never met a man I didn't like", Will Rogers had another great little ditty I've always remembered. It went: "It's not what you don't know that'll hurt you, it's what you do know that ain't so." We all know or subscribe to many IT "truisms" that mostly have a strong basis in fact, in something in our professional careers, something we learned from others, lessons learned the hard way by ourselves, or by others who came before us. Unfortuntely, as these truisms spread throughout the community, the details—why they came about and the caveats that affect when they apply—tend to not spread along with them. We all have a tendency to look for, and latch on to, small "rules" or principles that we can use to avoid doing a complete exhaustive analysis for every decision. But even though they are correct much of the time, when we sometimes misapply them, we pay a penalty that could be avoided by understooding the details behind them. For example, when user-defined functions were first introduced in SQL Server it became "common knowledge" within a year or so that they had extremely bad performance (because it required a re-compilation for each use) and should be avoided. This "trusim" still increases many database developers' aversion to using UDFs, even though Microsoft's introduction of InLine UDFs, which do not suffer from this issue at all, mitigates this issue substantially. In recent years I have run into numerous DBAs who still believe you should "never" use UDFs, because of this. What other common not-so-"trusims" do you know, which many developers believe, that are not quite as universally true as is commonly understood, and which the developer community would benefit from being better educated about? Please include why it was "true" to start off with, and under what circumstances it's not true. Limit responses to issues that are technical, where the "common" application of a "rule or principle" is in fact correct most of the time, or was correct back when it was first elucidated, but—in the edge cases, or because of not understanding the principle thoroughly, because technology has changed since it first spread, or applying the rule today without understanding the details behind the rule—can easily backfire or cause the opposite of the intended effect.

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  • Representing xml through a single class

    - by Charles
    I am trying to abstract away the difficulties of configuring an application that we use. This application takes a xml configuration file and it can be a bit bothersome to manually edit this file, especially when we are trying to setup some automatic testing scenarios. I am finding that reading xml is nice, pretty easy, you get a network of element nodes that you can just go through and build your structures quite nicely. However I am slowly finding that the reverse is not quite so nice. I want to be able to build a xml configuration file through a single easy to use interface and because xml is composed of a system of nodes I am having a lot of struggle trying to maintain the 'easy' part. Does anyone know of any examples or samples that easily and intuitively build xml files without declaring a bunch of element type classes and expect the user to build the network themselves? For example if my desired xml output is like so <cook version="1.1"> <recipe name="chocolate chip cookie"> <ingredients> <ingredient name="flour" amount="2" units="cups"/> <ingredient name="eggs" amount="2" units="" /> <ingredient name="cooking chocolate" amount="5" units="cups" /> </ingredients> <directions> <direction name="step 1">Preheat oven</direction> <direction name="step 2">Mix flour, egg, and chocolate</direction> <direction name="step 2">bake</direction> </directions> </recipe> <recipe name="hot dog"> ... How would I go about designing a class to build that network of elements and make one easy to use interface for creating recipes? Right now I have a recipe object, an ingredient object, and a direction object. The user must make each one, set the attributes in the class and attach them to the root object which assembles the xml elements and outputs the formatted xml. Its not very pretty and I just know there has to be a better way. I am using python so bonus points for pythonic solutions

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  • Test for undefined references in Linux

    - by Charles
    Is there a built in linux utility that I can use to test a newly compiled shared library for external undefined references? Gcc seems to be intelligent enough to check for undefined symbols in my own binary, but if the symbol is a reference to another library gcc does not check at link time. Instead I only get the message when I try to link to my new library from another program. It seems a little silly to get undefined reference messages in a library when I am compiling a different project so I want to know if I can do a check on all references internal and external when I build the library not when I link to it. Example error: make -C UnitTests debug make[1]: Entering directory `~/projects/Foo/UnitTests` g++ [ tons of objects ] -L../libbar/bin -lbar -o UnitTests libbar.so: undefined reference to `DoSomethingFromAnotherLibrary` collect2: ld returned 1 exit status make[1]: *** [~/projects/Foo/UnitTests] Error 1

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  • Putting $$s in the middle of an `equation` environment: why doesn't Latex complain?

    - by Charles Stewart
    I was surprised that the Latex code from a recent question didn't throw up any errors, and even more surprised on further investigation, that Crowley's explanation seems to be true. My intuition about the \begin{equation} ... \end{equation} code is clearly off, what's really going on? Consider this, slightly adapted code: \begin{equation} 1: e^{i\pi}+1=0 $$ 2: B\"ob $$ 3: e=mc^2 \end{equation} This seems to prove that Crowley's explanation of such code, namely that "What that code says to LaTeX is begin equation, end it, begin it again, typeset definition of tangens and end the equation" is right: lines 1&3 can only be typeset in maths mode, line 2 only in text mode. Shouldn't Latex see that the \end{equation} is ending a display math that wasn't started by the \begin{equation}?

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  • Any way to set or overwrite the __line__ and __file__ metadata?

    - by charles.merriam
    I'm writing some code that needs to change function signatures. Right now, I'm using Simionato's FunctionMaker class, which uses the (hacky) inspect module, and does a compile. Unfortunately, this still loses the line and file metadata. Does anyone know: If it is possible to overwrite these values in some odd way? If hacking up a class with a complex getattribute() to intercept the values and also try to make the class looks like a function is any more possible than a moose with a flying nun hat? Is there an alternative to the (hacky) inspect module? PEP 362 is dead dead dead? I know decorators and cPickle users fight with this. What other situations is the read only metadata in people's way? I appreciate any insights. Thank you.

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  • Pass Types as arguments to a function in Haskell?

    - by Charles Peng
    The following two functions are extremely similar. They read from a [String] n elements, either [Int] or [Float]. How can I factor the common code out? I don't know of any mechanism in Haskell that supports passing types as arguments. readInts n stream = foldl next ([], stream) [1..n] where next (lst, x:xs) _ = (lst ++ [v], xs) where v = read x :: Int readFloats n stream = foldl next ([], stream) [1..n] where next (lst, x:xs) _ = (lst ++ [v], xs) where v = read x :: Float I am at a beginner level of Haskell, so any comments on my code are welcome.

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  • GDI+: Set all pixels to given color

    - by Charles
    What is the best way to set the RGB components of every pixel in a System.Drawing.Bitmap to a single, solid color? If possible, I'd like to avoid manually looping through each pixel to do this. Note: I want to keep the same alpha component from the original bitmap. I only want to change the RGB values. I looked into using a ColorMatrix or ColorMap, but I couldn't find any way to set all pixels to a specific given color with either approach.

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  • Is there a better way to deal with reserved characters when parsing XML/JSON data on the iPhone?

    - by Charles S.
    The following code works, but it's ugly and creates a bunch of autoreleased objects. I'm using similar code for parsing reserved HTML characters as well (for quotes, & symbols, etc). I'm just wondering... Is there a cleaner way? NSString *result = [[NSString alloc] initWithString:userInput]; NSString *result2 = [result stringByReplacingOccurrencesOfString:@"#" withString:@"\%23"]; NSString *result3 = [result2 stringByReplacingOccurrencesOfString:@" " withString:@"\%20"]; formatted = [[result3 stringByReplacingOccurrencesOfString:@"&" withString:@"\%26"] retain]; [result release];

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  • How can I access this nested array within my JSON object?

    - by Charles
    I'm using PHP to return a json_encode()'d array for use in my Javascript code. It's being returned as: {"parent1[]":["child1","child2","child2"],"parent2[]":["child1"]} By using the following code, I am able to access parent2 > child1 $.getJSON('myfile.php', function(data) { for (var key in data) { alert(data[key]); } } However, this doesn't give me access to child1, child2, child, of parent1. Alerting the key by itself shows 'parent1' but when I try to alert it's contents, I get undefined. I figured it would give me an object/array? How do I access the children of parent1? data[key][0] ?

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  • Give the mount point of a path

    - by Charles Stewart
    The following, very non-robust shell code will give the mount point of $path: (for i in $(df|cut -c 63-99); do case $path in $i*) echo $i;; esac; done) | tail -n 1 Is there a better way to do this? Postscript This script is really awful, but has the redeeming quality that it Works On My Systems. Note that several mount points may be prefixes of $path. Examples On a Linux system: cas@txtproof:~$ path=/sys/block/hda1 cas@txtproof:~$ for i in $(df -a|cut -c 57-99); do case $path in $i*) echo $i;; esac; done| tail -1 /sys On a Mac osx system cas local$ path=/dev/fd/0 cas local$ for i in $(df -a|cut -c 63-99); do case $path in $i*) echo $i;; esac; done| tail -1 /dev Note the need to vary cut's parameters, because of the way df's output differs: indeed, awk is better. Answer It looks like munging tabular output is the only way within the shell, but df /dev/fd/impossible | tail -1 | awk '{ print $NF}' is a big improvement on what I had. Note two differences in semantics: firstly, df $path insists that $path names an existing file, the script I had above doesn't care; secondly, there are no worries about dereferncing symlinks. It's not difficult to write Python code to do the job.

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  • Is there any class in the .NET Framework to represent a holding container for objects?

    - by Charles Prakash Dasari
    I am looking for a class that defines a holding structure for an object. The value for this object could be set at a later time than when this container is created. It is useful to pass such a structure in lambdas or in callback functions etc. Say: class HoldObject<T> { public T Value { get; set; } public bool IsValueSet(); public void WaitUntilHasValue(); } // and then we could use it like so ... HoldObject<byte[]> downloadedBytes = new HoldObject<byte[]>(); DownloadBytes("http://www.stackoverflow.com", sender => downloadedBytes.Value = sender.GetBytes()); It is rather easy to define this structure, but I am trying to see if one is available in FCL. I also want this to be an efficient structure that has all needed features like thread safety, efficient waiting etc. Any help is greatly appreciated.

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  • How can install sqlite-ruby on linux when sqlite3 is not in /usr/local ?

    - by Charles
    I am trying to install sqlite3 and sqlite-ruby (ruby 1.8.6) on a linux box where I do not have root. I downloaded the sqlite3 source, binaries, and shared library and placed them all in a directory called sqlite3 I then try to install sqlite-ruby using gem install sqlite-ruby --with-sqlite-dir=the_path_sqlite/sqlite3 but I keep getting the error... checking for main() in -lsqlite... no checking for sqlite.h... no * extconf.rb failed * Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options. Provided configuration options: --with-opt-dir --without-opt-dir --with-opt-include --without-opt-include=${opt-dir}/include --with-opt-lib --without-opt-lib=${opt-dir}/lib --with-make-prog --without-make-prog --srcdir=. --curdir --ruby=/data/scratch/bettbra/common/packages/ruby-1.8.6/bin/ruby --with-sqlite-dir --with-sqlite-include --without-sqlite-include=${sqlite-dir}/include --with-sqlite-lib --without-sqlite-lib=${sqlite-dir}/lib --with-sqlitelib --without-sqlitelib

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