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  • Passing control references as ref parameters

    - by Enmanuel
    Hi everyone. Please help me out here because im getting kind of confused.. I have a form in a C# winforms project and a couple of methods that are suposed to perform some tasks for this particular form and all derived ones, so one of those helper methods can make the example.. this one should fill comboboxes with a dataset. Its working properly now but when i coded the method with this signature protected void FillComboBox(kComboBox target, IEntClass_DA entity) { target.DataSource = entity.GetList().Tables[0]; target.DisplayMember = "name"; target.ValueMember = "id"; } I saw that the displayMember and ValueMember in the comboboxes were not holding the values after the method call. I just thought I should use ref parameters so the asignments are not wasted in read-only reference variables. It was ok by then but later, making an exercise of passing the whole form as a parameter I was warned by the compiler with the notice that this could not be passed as a ref parameter because it is read-only. Fine then, I keep working and see that even without the ref keyword i can use the ref variable from the form, update some properties and see the changes. So whats happening here: passing a reference of the control to the helper method gives me ability to change its members even when not using the ref parameter?? Thanks.

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  • Using MD5 to generate an encryption key from password?

    - by Charles
    I'm writing a simple program for file encryption. Mostly as an academic exercise but possibly for future serious use. All of the heavy lifting is done with third-party libraries, but putting the pieces together in a secure manner is still quite a challenge for the non-cryptographer. Basically, I've got just about everything working the way I think it should. I'm using 128-bit AES for the encryption with a 128-bit key length. I want users to be able to enter in variable-length passwords, so I decided to hash the password with MD5 and then use the hash as the key. I figured this was acceptable--the key is always supposed to be a secret, so there's no reason to worry about collision attacks. Now that I've implemented this, I ran across a couple articles indicating that this is a bad idea. My question is: why? If a good password is chosen, the cipher is supposed to be strong enough on its own to never reveal the key except via an extraordinary (read: currently infeasible) brute-force effort, right? Should I be using something like PBKDF2 to generate the key or is that just overkill for all but the most extreme cryptographic applications?

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  • UnsatisfiedLinkError: The specified procedure could not be found

    - by matt
    I'm writing some JNI code in C++ to be called from an applet on Windows XP. I've been able to successfully run the applet and have the JNI library loaded and called, even going so far as having it call functions in other DLLs. I got this working by setting up the PATH system environment variable to include the directory all of my DLLs are in. So, the problem, is that I add another call that uses a new external DLL, and suddenly when loading the library, an UnsatisfiedLinkError is thrown. The message is: 'The specified procedure could not be found'. This doesn't seem to be a problem with a missing dependent DLL, because I can remove a dependent DLL and get a different message about dependent DLL missing. From what I've been able to find online, it appears that this message means that a native Java function implementation is missing from the DLL, but it's odd that it works fine without this extra bit of code. Does anyone know what might be causing this? What kinds of things can give a 'The specified procedure could not be found' messages for an UnsatisifedLinkError?

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  • Why do properties behave this way?

    - by acidzombie24
    from http://csharpindepth.com/Articles/Chapter8/PropertiesMatter.aspx using System; struct MutableStruct { public int Value { get; set; } public void SetValue(int newValue) { Value = newValue; } } class MutableStructHolder { public MutableStruct Field; public MutableStruct Property { get; set; } } class Test { static void Main(string[] args) { MutableStructHolder holder = new MutableStructHolder(); // Affects the value of holder.Field holder.Field.SetValue(10); // Retrieves holder.Property as a copy and changes the copy holder.Property.SetValue(10); Console.WriteLine(holder.Field.Value); Console.WriteLine(holder.Property.Value); } } 1) Why is a copy (of Property?) being made? 2) When changing the code to holder.Field.value and holder.Property.value = 10 i get the error below. That just blew my mind Error 1 Cannot modify the return value of 'MutableStructHolder.Property' because it is not a variable Why would i ever not be allowed to assign a value inside of a property!?! both property are get/set! and finally WHY would you EVER want behavior mentioned in 1 and 2. (It never came up for me, i always used get only properties). Please explain well, i cant imagine ever wanting the 2nd much less then the first. It is just so weird to me.

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  • php get, random records, and the back button

    - by Andrew Heath
    My site has a library full of games, nations, game scenarios, etc. library.php is given a type=___ & id=___ for example library.php?type=scenario&id=ABCD001 library.php saves the id to a session variable and loads an include appropriate for the type This all works just dandy. Now, I wanted to give my users the option of pulling up a random scenario. To do that, I added a special id to the logic within lib-scenario.php (the include) such that if given library.php?type=scenario&id=random the include knows to run an alternate query for a random record rather than for the actual id This also works just dandy... unless someone hits the Random Scenario button two+ times in a row, and decides that the previous random scenario was way cooler, I want to go back to that. Because the http address is always directory/library.php?type=scenario&id=random no matter how many times you click Random Scenario, as soon as you click back you'll be taken to the last page with an alternate address you visited. So, if you start at the Home page, and hit Random Scenario 35 times, then decide the 34th one was what you wanted and click BACK, you'll be put back onto the Home page. I must admit this was not a problem I had anticipated. One of my testers was the first to have the urge to back-up in the random scenario stream and here we are. How can I add back-up functionality to my script?

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  • centos: linking lib that doesn't have a .pc file for pkg-config

    - by Paulie
    I'm trying to compile svg2pdf on centos. I think I've managed to get the required dependencies installed using yum: sudo yum install librsvg2 sudo yum install cairo The Makefile contains: MYCFLAGS=`pkg-config --cflags librsvg-2.0 cairo-pdf` -Wall -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations - Wnested-externs -fno-strict-aliasing MYLDFLAGS=`pkg-config --libs librsvg-2.0 cairo-pdf` After typing 'make', the first couple of lines of output are: cc `pkg-config --cflags librsvg-2.0 cairo-pdf` -Wall -Wpointer-arith -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations -Wnested-externs -fno-strict-aliasing `pkg-config --libs librsvg-2.0 cairo-pdf` svg2pdf.c -o svg2pdf Package librsvg-2.0 was not found in the pkg-config search path. Perhaps you should add the directory containing `librsvg-2.0.pc' to the PKG_CONFIG_PATH environment variable No package 'librsvg-2.0' found There is no librsvg-2.0.pc on this system (but there is when I installed this using macports on my macbookpro). How should I get this package linked? Should I change the Makefile, and if so, to what? Should I generate the .pc files, and if so, how? Or is there another way to resolve this? Or, has anyone been successful at installing svg2pdf on centos, and, if so, how did you manage it? I don't have much experience on linux, so I might be missing something obvious.

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  • Loading google datatable using ajax/json

    - by puff
    I can't figure out how to load a datable using ajax/json. Here is my json code in a remote file (pie.json) { cols: [{id: 'task', label: 'Task', type: 'string'}, {id: 'hours', label: 'Hours per Day', type: 'number'}], rows: [{c:[{v: 'Work'}, {v: 11}]}, {c:[{v: 'Eat'}, {v: 2}]}, {c:[{v: 'Commute'}, {v: 2}]}, {c:[{v: 'Watch TV'}, {v:2}]}, {c:[{v: 'Sleep'}, {v:7, f:'7.000'}]} ] } This is what I have tried so far but it doesn't work. <script type="text/javascript" src="http://www.google.com/jsapi"></script> <script type="text/javascript"> google.load("visualization", "1", {packages:["piechart"]}); function ajaxjson() { jsonreq=GetXmlHttpObject(); jsonreq.open("GET", "pie.json", true); jsonreq.onreadystatechange = jsonHandler; jsonreq.send(null); } function jsonHandler() { if (jsonreq.readyState == 4) { var res = jsonreq.responseText; google.setOnLoadCallback(drawChart); function drawChart() { var data = new google.visualization.DataTable(res, 0.6) var chart = new google.visualization.PieChart(document.getElementByI('chart_div')); chart.draw(data, {width: 400, height: 240, is3D: true}); } // end drawChart } // end if } // end jsonHandler function GetXmlHttpObject() { var xmlHttp=null; xmlHttp=new ActiveXObject("Microsoft.XMLHTTP"); return xmlHttp; } Things work perfectly if I replace the 'res' variable with the actual code in pie.json. Any help would be greatly appreciated.

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  • Sourcing a script file in bash before starting an executable

    - by abigagli
    Hi, I'm trying to write a bash script that "wraps" whatever the user wants to invoke (and its parameters) sourcing a fixed file just before actually invoking it. To clarify: I have a "ConfigureMyEnvironment.bash" script that must be sourced before starting certain executables, so I'd like to have a "LaunchInMyEnvironment.bash" script that you can use as in: LaunchInMyEnvironment <whatever_executable_i_want_to_wrap> arg0 arg1 arg2 I tried the following LaunchInMyEnvironment.bash: #!/usr/bin/bash launchee="$@" if [ -e ConfigureMyEnvironment.bash ]; then source ConfigureMyEnvironment.bash; fi exec "$launchee" where I have to use the "launchee" variable to save the $@ var because after executing source, $@ becomes empty. Anyway, this doesn't work and fails as follows: myhost $ LaunchInMyEnvironment my_executable -h myhost $ /home/me/LaunchInMyEnvironment.bash: line 7: /home/bin/my_executable -h: No such file or directory myhost $ /home/me/LaunchInMyEnvironment.bash: line 7: exec: /home/bin/my_executable -h: cannot execute: No such file or directory That is, it seems like the "-h" parameter is being seen as part of the executable filename and not as a parameter... But it doesn't really make sense to me. I tried also to use $* instead of $@, but with no better outcoume. What I'm doing wrong? Andrea.

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  • Java JSTL / EL: nesting

    - by NoozNooz42
    I really don't know how to name this question, it's great if anyone with 2K+ rep can edit this title to better reflect my question (the fact that I can't name this easily is probably why I can't Google the solution). I've got this, which is working: <c:choose> <c:when test="${sometest}"> Hello, world! </c:when> <c:otherwise> <fmt:message key="${page.title}" /> </c:otherwise> </c:choose> And I want to change it to this: <c:choose> <c:when test="${sometest}"> <c:set var="somevar" scope="page" value="Hello, world!"/> </c:when> <c:otherwise> <c:set var="somevar" scope="page" value="<fmt:message key="${page.title}">" </c:otherwise> </c:choose But of course the following line ain't correct: <c:set var="somevar" scope="page" value="<fmt:message key="${page.title}">" How can I assign to the somevar variable the string resulting from a call?

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  • parameter for xcodebuild for using latest sdk.

    - by Maciek Sawicki
    I using ant exec task to execute xcodebuild to build some iOS projects hudson. I would like to be able to crate script that way that allows not to specify sdk version, because after updating sdk on hudson slave or my iOS projects all my projects failing.... There is is nice option in xcode since sdk 4.2 in target setup Base SDK - Latest iOS and I don't have to provide -sdk param in xcodebuild command, but then (i think) it's taken from xcode project and it's bad because then some one can change target from simulator to device accidentally during commit. I need something that is constant. I will prefer not to use env variable because I would like to be able to run this ant task also on dev machines and would like not have to renember about setting it on all machines. Unfortunately xcodebuild -showsdk gives only: Mac OS X SDKs: Mac OS X 10.4 -sdk macosx10.4 Mac OS X 10.5 -sdk macosx10.5 Mac OS X 10.6 -sdk macosx10.6 iOS SDKs: iOS 4.2 -sdk iphoneos4.2 iOS Simulator SDKs: Simulator - iOS 3.2 -sdk iphonesimulator3.2 Simulator - iOS 4.0 -sdk iphonesimulator4.0 Simulator - iOS 4.1 -sdk iphonesimulator4.1 Simulator - iOS 4.2 -sdk iphonesimulator4.2 I need something like -sdk iphoneosLatest. My only idea is to pare output of xcodebuild -showsdk with some script, but I don't like this idea.

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  • problem in json response from server to client using jquery

    - by user1400
    hello i try to use ajax and zend framework in my application , i could pass variable to server but i can not get data from server , it does not return values, it return all html code page, where is my mistake? or should i config other thing? $('#myForm').submit(function($e){ $e.preventDefault(); var $paramToServer=$("#myForm").serialize(); $.ajax({ type:'POST', url:'test', data:$paramToServer , success:function(re){ var res = $.evalJSON(re); console.log(res.id); // to see in firebog }, dataType:'json' }); }); public function testAction() { $this->_helper->getHelper('viewRenderer')->setNoRender(); //disable layout Zend_Layout::getMvcInstance()->disableLayout(); $name=$this->getRequest()->getParam ( 'name' ); //pass $name to server $return = array( 'id' => '5', 'family' => 'hello ', ); $return = Zend_Json::encode( $return); // Response $this->getResponse()->setBody($return); } thanks

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  • Direct invocation vs indirect invocation in C

    - by Mohit Deshpande
    I am new to C and I was reading about how pointers "point" to the address of another variable. So I have tried indirect invocation and direct invocation and received the same results (as any C/C++ developer could have predicted). This is what I did: int cost; int *cost_ptr; int main() { cost_ptr = &cost; //assign pointer to cost cost = 100; //intialize cost with a value printf("\nDirect Access: %d", cost); cost = 0; //reset the value *cost_ptr = 100; printf("\nIndirect Access: %d", *cost_ptr); //some code here return 0; //1 } So I am wondering if indirect invocation with pointers has any advantages over direct invocation or vice-versa. Some advantages/disadvantages could include speed, amount of memory consumed performing the operation (most likely the same but I just wanted to put that out there), safeness (like dangling pointers) , good programming practice, etc. 1Funny thing, I am using the GNU C Compiler (gcc) and it still compiles without the return statement and everything is as expected. Maybe because the C++ compiler will automatically insert the return statement if you forget.

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  • 'strcpy' error and warning

    - by Leejo
    I'm getting a 'strcpy' error and warning for the following lines: _tcscpy(strCommandLine,_T("MyProgram.exe /param1")); _tcscpy(strApplicationName,_T("MyProgram.exe")); Not sure why I'm getting a 'strcpy' error or warning since I'm not using 'strcpy'. The only lines related to this is: LPCTSTR strApplicationName; LPTSTR strCommandLine; _tcscpy(strCommandLine,_T("MyProgram.exe /param1")); //warning is on this line _tcscpy(strApplicationName,_T("MyProgram.exe")); //error is on this line The output is: 1c:\documents and settings\X.X\my documents\sandbox\sample.cpp(52) : warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details. 1 c:\program files\microsoft visual studio 8\vc\include\string.h(74) : see declaration of 'strcpy' 1c:\documents and settings\X.X\my documents\sandbox\sample.cpp(53) : error C2664: 'strcpy' : cannot convert parameter 1 from 'LPCTSTR' to 'char *' 1 Conversion loses qualifiers Any ideas on what this could means? These are my headers: iostream windows.h stdio.h tchar.h winnt.h

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  • ClassNotFoundException when connecting to Mysql with JDBC

    - by Jacob Lyles
    I'm getting the following error when I try to run a simple Java JDBC program at the command line: Exception in thread "main" java.lang.NoClassDefFoundError: LoadDriver/java Caused by: java.lang.ClassNotFoundException: LoadDriver.java at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:315) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:330) at java.lang.ClassLoader.loadClass(ClassLoader.java:250) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:398) Here's the simple Java program, copied right out of the JDBC docs: import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; // Notice, do not import com.mysql.jdbc.* // or you will have problems! public class LoadDriver { public static void main(String[] args) { try { // The newInstance() call is a work around for some // broken Java implementations Class.forName("com.mysql.jdbc.Driver").newInstance(); } catch (Exception ex) { throw ex; // handle the error } } } Problem is, I'm bloody sure my bash shell $ClASSPATH variable is pointed at the correct .jar file. To be sure, I copied the JDBC .jar to the same directory as my program and ran it as follows: java -classpath ./mysql-connector-java-5.1.12-bin.jar LoadDriver.java I still get the same error. I'm running under Mac OSX, if it matters.

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  • What is happening in this T-SQL code?

    - by Ben McCormack
    I'm just starting to learn T-SQL and could use some help in understanding what's going on in a particular block of code. I modified some code in an answer I received in a previous question, and here is the code in question: DECLARE @column_list AS varchar(max) SELECT @column_list = COALESCE(@column_list, ',') + 'SUM(Case When Sku2=' + CONVERT(varchar, Sku2) + ' Then Quantity Else 0 End) As [' + CONVERT(varchar, Sku2) + ' - ' + Convert(varchar,Description) +'],' FROM OrderDetailDeliveryReview Inner Join InvMast on SKU2 = SKU and LocationTypeID=4 GROUP BY Sku2 , Description ORDER BY Sku2 Set @column_list = Left(@column_list,Len(@column_list)-1) Select @column_list ---------------------------------------- 1 row is returned: ,SUM(Case When Sku2=157 Then Quantity Else 0 End) As [157 -..., SUM(Case ... The T-SQL code does exactly what I want, which is to make a single result based on the results of a query, which will then be used in another query. However, I can't figure out how the SELECT @column_list =... statement is putting multiple values into a single string of characters by being inside a SELECT statement. Without the assignment to @column_list, the SELECT statement would simply return multiple rows. How is it that by having the variable within the SELECT statement that the results get "flattened" down into one value? How should I read this T-SQL to properly understand what's going on?

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  • How can I share variables between a base class and subclass in Perl?

    - by Jonathan
    I have a base class like this: package MyClass; use vars qw/$ME list of vars/; use Exporter; @ISA = qw/Exporter/; @EXPORT_OK = qw/ many variables & functions/; %EXPORT_TAGS = (all => \@EXPORT_OK ); sub my_method { } sub other_methods etc { } --- more code--- I want to subclass MyClass, but only for one method. package MySubclass; use MyClass; use vars qw/@ISA/; @ISA = 'MyClass'; sub my_method { --- new method } And I want to call this MySubclass like I would the original MyClass, and still have access to all of the variables and functions from Exporter. However I am having problems getting the Exporter variables from the original class, MyClass, to export correctly. Do I need to run Exporter again inside the subclass? That seems redundant and unclear. Example file: #!/usr/bin/perl use MySubclass /$ME/; -- rest of code But I get compile errors when I try to import the $ME variable. Any suggestions?

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  • (EXCEL)VBA Spin button which steps through in an sql databases date time

    - by Gulredy
    I have an sql Database table in MySQL which have lots of rows with varied date time values. For example: 2012-08-21 10:10:00 <-- with these date there are around 12 rows 2012-08-21 15:31:00 <-- with these date there are around 5 rows 2012-08-22 11:40:00 <-- with these date there are around 10 rows 2012-08-22 12:17:00 <-- with these date there are around 9 rows 2012-08-22 12:18:00 <-- with these date there are around 7 rows 2012-08-25 07:21:00 <-- with these date there are around 6 rows If the user clicks on the SpinButton1_SpinUp() or SpinButton1_SpinDown() button then it should do the following: The SpinButton1_SpinUp() button should filter out those data from an sql table which is the next after what we are currently on now. Example: We have currently selected: 2012-08-21 15:31:00. The user hits the SpinUp button then the program selects those date from the database, which is the next higher value like this one: 2012-08-22 11:40:00. So the user hits the SpinUp button the data which is selected in the database will change from those with date: 2012-08-21 15:31:00 to those with date: 2012-08-22 11:40:00 The SpinButton1_SpinDown() will do exactly the reverse of the SpinUp button. When the user hits the SpinDown button the data which is selected in the database will change from those with date: 2012-08-21 15:31:00 to those with date 2012-08-21 10:10:00 So I think the date which we are currently on, should be stored in a variable. But on button hit not every bigger or lower data should be selected in the database, only those which are the closest bigger or the closest lower date. How can I do this? I hope I described my problem understandable. My native language is not english, so misunderstandings can occur! Please ask if you don't understand something! Thank you for reading!

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  • scaling svg paths in Raphael 2.1

    - by user1229001
    I'm using SVG paths from a wikimedia commons map of the US. I've singled out Pennsylvania with its counties. I'm feeding the paths out of a database and using Raphael 2.1 to put them on the page. Because in the original map, Pennsylvania was so small and set at an angle, I'd like to scale up the paths and rotate Pa. so that it isn't on an angle. When I try to use Raphael's transform method, all the counties look strange and overlapped. I gave up on setting the viewBox when I heard that it doesn't work in all browsers. Anyone have any ideas? Here is my code: $(document).ready(function() { var $paths = []; //array of paths var $thisPath; //variable to hold whichever path we're drawing $.post('getmapdata.php', function(data){ var objData = jQuery.parseJSON(data); for (var i=0; i<objData.length; i++) { $paths.push(objData[i].path); //$counties.push(objData[i].name); }//end for drawMap($paths); }) function drawMap(data) { // var map = new Raphael(document.getElementById('map_div_id'),0, 0); var map = new Raphael(0, 0, 520, 320); //map.setViewBox(0,0,500,309, true); for (var i = 0; i < data.length; i++) { var thisPath = map.path(data[i]); thisPath.transform(s2); thisPath.attr({stroke:"#FFFFFF", fill:"#CBCBCB","stroke-width":"0.5"}); } //end cycling through i }//end drawMap });//end program

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  • Q on Python serialization/deserialization

    - by neil
    What chances do I have to instantiate, keep and serialize/deserialize to/from binary data Python classes reflecting this pattern (adopted from RFC 2246 [TLS]): enum { apple, orange } VariantTag; struct { uint16 number; opaque string<0..10>; /* variable length */ } V1; struct { uint32 number; opaque string[10]; /* fixed length */ } V2; struct { select (VariantTag) { /* value of selector is implicit */ case apple: V1; /* VariantBody, tag = apple */ case orange: V2; /* VariantBody, tag = orange */ } variant_body; /* optional label on variant */ } VariantRecord; Basically I would have to define a (variant) class VariantRecord, which varies depending on the value of VariantTag. That's not that difficult. The challenge is to find a most generic way to build a class, which serializes/deserializes to and from a byte stream... Pickle, Google protocol buffer, marshal is all not an option. I made little success with having an explicit "def serialize" in my class, but I'm not very happy with it, because it's not generic enough. I hope I could express the problem. My current solution in case VariantTag = apple would look like this, but I don't like it too much import binascii import struct class VariantRecord(object): def __init__(self, number, opaque): self.number = number self.opaque = opaque def serialize(self): out = struct.pack('>HB%ds' % len(self.opaque), self.number, len(self.opaque), self.opaque) return out v = VariantRecord(10, 'Hello') print binascii.hexlify(v.serialize()) >> 000a0548656c6c6f Regards

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  • Passing an NSDate

    - by Garry
    I'm new to the iPhone and objective-c and I am still trying to get my head around ownership of objects so bear with me. I have a DOBViewController that has a datepicker on it. I have created a custom init method: -(id)initWithInitialDate(NSDate *)initialDate; Another view controller has a date instance declared (NSDate *dob) that holds a value. I would like to pass this to the DOBViewController so that it can scroll the datepicker to the passed value. Here is the custom init method: - (id)initWithInitialDate:(NSDate *)initialDate { // Initialise ourselves self = [super init]; // Set the date of the date picker if (initialDate != nil) { datePicker.date = initialDate; } else { // Set it to today datePicker.date = [NSDate date]; } return self; } This is how I am sending the dob NSDate object: DOBViewController *dobViewController = [[DOBViewController alloc] initWithInitialDate:dob]; Where dob is a variable of type NSDate that is declared in the header file. This doesn't seem to work as initialDate is always NULL. What am I doing wrong?

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  • How to cast sockaddr_storage and avoid breaking strict-aliasing rules

    - by sinoth
    I'm using Beej's Guide to Networking and came across an aliasing issue. He proposes a function to return either the IPv4 or IPv6 address of a particular struct: 1 void *get_in_addr( struct sockaddr *sa ) 2 { 3 if (sa->sa_family == AF_INET) 4 return &(((struct sockaddr_in*)sa)->sin_addr); 5 else 6 return &(((struct sockaddr_in6*)sa)->sin6_addr); 7 } This causes GCC to spit out a strict-aliasing error for sa on line 3. As I understand it, it is because I call this function like so: struct sockaddr_storage their_addr; ... inet_ntop(their_addr.ss_family, get_in_addr((struct sockaddr *)&their_addr), connection_name, sizeof connection_name); I'm guessing the aliasing has to do with the fact that the their_addr variable is of type sockaddr_storage and another pointer of a differing type points to the same memory. Is the best way to get around this sticking sockaddr_storage, sockaddr_in, and sockaddr_in6 into a union? It seems like this should be well worn territory in networking, I just can't find any good examples with best practices. Also, if anyone can explain exactly where the aliasing issue takes place, I'd much appreciate it.

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  • What's the largest (most complex) PHP algorithm ever implemented in a single monolithic PHP script?

    - by Alex R
    I'm working on a tool which converts PHP code to Scala. As one of the finishing touches, I'm in need of a really good (er, somewhat biased) benchmark. By dumb luck my first benchmark attempt was with some code which uses bcmath extensively, which unfortunately is 1000x slower in Java, making the Scala code 22x slower overall than the original PHP. So I'm looking for some meaningful PHP benchmark with the following characteristics: The source needs to be in a single file. I need it to be simple to setup - no databases, hard-to-find input files, etc. Simple text input and output preferred. It should not use features that are slow in Java (BigInteger, trigonometric functions, etc). It should not use exoteric or dynamic PHP functions (e.g. no "eval" or "variable vars"). It should not over-rely on built-in libraries, e.g. MD5, crypt, etc. It should not be I/O bound. A CPU-bound memory-hungry algorithm is preferred. Basically, intensive OO operations, integer and string manipulation, recursion, etc would be great. Thanks

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  • Accessing class member variables inside a BackgroundWorker's DoWork event handler, and other Backgro

    - by Justin
    Question 1 In the DoWork event handler of a BackgroundWorker, is it safe to access (for both reading and writing) member variables of the class that contains the BackgroundWorker? Is it safe to access other variables that are not declared inside the DoWork event handler itself? Obviously DoWork should not be accessing any UI objects of, say, a WinForms application, as the UI should only be updated from the UI thread. But what about accessing other (not UI-related) member variables? The reason why I ask is that I've seen the occasional comment come up while Googling saying that accessing member variables is not allowed. The only example I can find at the moment is a comment on this MSDN page, which says: Note, that the BGW can cause exceptions if it attempts to access or modify class level variables. All data must be passed to it by delegates and events. And also: NEVER. NEVER. Never try to reference variables not declared inside of DoWork. It may seem to work at times, but in reality you are just getting lucky. As far as I know, MSDN itself does not document any restrictions of this kind (although if I'm wrong, I'd appreciate a link). But comments like these do seem to pop up every now and again. (Of course if DoWork does access/modify a member variable that could be accessed/modified by the main thread at the same time, it is necessary to synchronise access to that field, eg by using a locking object. But the above quotes seem to require a blanket ban of accessing member variables, rather than just synchronising access!) Question 2 To make this into a more general question, are there any other (not documented?) restrictions that users of the BackgroundWorker should be aware of, aside from the above? Any "best practices", perhaps?

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  • Rails 3 : create two dimensional hash and add values from a loop

    - by John
    I have two models : class Project < ActiveRecord::Base has_many :ticket attr_accessible .... end class Ticket < ActiveRecord::Base belongs_to :project attr_accessible done_date, description, .... end In my ProjectsController I would like to create a two dimensional hash to get in one variable for one project all tickets that are done (with done_date as key and description as value). For example i would like a hash like this : What i'm looking for : @tickets_of_project = ["done_date_1" => ["a", "b", "c"], "done_date_2" => ["d", "e"]] And what i'm currently trying (in ProjectsController) ... def show # Get current project @project = Project.find(params[:id]) # Get all dones tickets for a project, order by done_date @tickets = Ticket.where(:project_id => params[:id]).where("done_date IS NOT NULL").order(:done_date) # Create a new hash @tickets_of_project = Hash.new {} # Make a loop on all tickets, and want to complete my hash @tickets.each do |ticket| # TO DO #HOW TO PUT ticket.value IN "tickets_of_project" WITH KEY = ticket.done_date ??** end end I don't know if i'm in a right way or not (maybe use .map instead of make a where query), but how can I complete and put values in hash by checking index if already exist or not ? Thanx :)

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  • In Perl, how can a subroutine get a coderef that points to itself?

    - by hillu
    For learning purposes, I am toying around with the idea of building event-driven programs in Perl and noticed that it might be nice if a subroutine that was registered as an event handler could, on failure, just schedule another call to itself for a later time. So far, I have come up with something like this: my $cb; my $try = 3; $cb = sub { my $rc = do_stuff(); if (!$rc && --$try) { schedule_event($cb, 10); # schedule $cb to be called in 10 seconds } else { do_other_stuff; } }; schedule_event($cb, 0); # schedule initial call to $cb to be performed ASAP Is there a way that code inside the sub can access the coderef to that sub so I could do without using an extra variable? I'd like to schedule the initial call like this. schedule_event( sub { ... }, 0); I first thought of using caller(0)[3], but this only gives me a function name, (__ANON__ if there's no name), not a code reference that has a pad attached to it.

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