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• C++ containers on classes, returning pointers

  - by otneil

  Hello, I'm having some trouble to find the best way to accomplish what I have in mind due to my inexperience. I have a class where I need to a vector of objects. So my first question will be: is there any problem having this: vector< AnyType container* and then on the constructor initialize it with new (and deleting it on the destructor)? Another question is: if this vector is going to store objects, shouldn't it be more like vector< AnyTipe* so they could be dynamically created? In that case how would I return an object from a method and how to avoid memory leaks (trying to use only STL)?

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• Freeing JavaScript object

  - by pion

  I am looking at the example from http://www.javascriptkit.com/javatutors/oopjs.shtml var person = new Object() person.name = "Tim Scarfe" person.height = "6Ft" But there is no mention how to "free" it in order to avoid memory leak. Will the following code free it? person = null; How do you free a JavaScript Object using "new Object()? How do you free a JavaScript Array allocated using "new Array(10)"? How do you free a JavaScript JSON allocated using "var json = {"width": 480, "height": 640}"? Thanks in advance for your help.

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• PHP: Safe way to store decryptable passwords

  - by Jammer

  I'm making an application in PHP and there is a requirement that it must be possible to decrypt the passwords in order to avoid problems in the future with switching user database to different system. What encryption/decryption algorithm would you suggest? Is it good idea to just store the encrypted value and then compare the future authentication attempts to that value? Are the passwords still as safe as MD5/SHA1 when the private key is not available to the attacker (Hidden in USB drive for example)? I should still use salting, right? What encryption libraries should I use for PHP?

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• MYSQL, Subquery Reference in Union

  - by christian

  Is there any way to reference a subquery in a union? I am trying to do something like the following, and would like to avoid a temporary table, but the subquery will be drawn from a much larger dataset so it makes sense to only do it once.. SELECT * FROM (SELECT * FROM ads WHERE state='FL' AND city='Maitland' AND page='home' ORDER BY RAND()) AS sq WHERE spot = 'full-banner' LIMIT 1 UNION SELECT * FROM sq WHERE spot = 'leaderboard' LIMIT 1 UNION SELECT * FROM sq WHERE spot = 'rectangle1' LIMIT 1 UNION SELECT * FROM sq WHERE spot = 'rectangle2' LIMIT 1 .... etc,, It's a shame that DISTINCT can't be specified for a single column of a result set.

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• VB.NET generates properties in the release build

  - by dattebayo

  I have a form and i drag and drop a control in VB.NET. I have a line say, private WithEvents radioButton RadioButton Also, I have a handler like, private void click(.....) Handles radioButton.Click { ... } Now, When I build this is .NET 3.5 in release mode, and see the generated code in reflector tool, the code is something like, Private Overridable Property radioButton As RadioButton . . . <AccessedThroughProperty("radioButton")> _ Private _radioButton As RadioButton Can someone tell me what is going on here? And how do I avoid the generation of new properties and fields? -datte

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• Cheapest ways to expose internet services

  - by tmow

  Hi all, we have developed/customized an internet site that provides functionalities like sharing, swap/barter, selling and rent any object/services trough public or private galleries and/or clubs. We'd like now to expose all or some of the services to the public, so that anybody can take advantage of our engine, but without spending too much as we rae running low on budget. At the moment we have developed some RSS interfaces for the public catalogs and is possible to use JQuery to query the engine. Do you have any advices on how to proceed here? We were thinking about something simple like framset, using openID like authentication, or similar technologies. Even if can be the coolest solution, we a would like to avoid the develop soap, rest or xmlrpc APIs as it takes a lot of time ( =money ) Do you have any super smart ideas?

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• Can profiler templates be migrated to newer versions of SQL Profiler?

  - by EBarr

  Is it possible to migrate Profiler templates to newer versions of SQL Server? In my case I want to take my SQL 2008 templates to 2012. I've tried (1) a straight file copy and (2) an export/import. In both cases the older templates run, but cannot be modified. Modifications result in the following error: I've got a bunch of custom templates and I'm trying to avoid recreating them by hand. Although, I guess that is the fallback position. Thoughts?

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• SQL Server Reporting Services Format Hours as Hours:Minutes

  - by Frank Schmitt

  I'm writing reports on SQL Server Reporting Server that have a number of hours grouped by, say, user, and a total calculated based on the sum of the values. Currently my query runs a stored proc that returns the hours as in HH:MM format, rather than decimal hours, as our users find that more intuitive. The problem occurs when I try and add up the column using an SSRS expression, because the SUM function isn't smart enough to handle adding up times in this format. Is there any way to: Display a time interval (in minutes or hours) in HH:MM format while having it calculated in decimal form? Or split up and calculate the total of the HH:MM text values to arrive at a total as an expression? I'd like to avoid having to write/run a second query just to get the total.

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• Audio input via HTML5?

  - by tibbon

  We have a VoIP application imVOX, and we are looking at various ways of expanding our reach. Part of that is writing an HTML5 application, but it requires the use of audio input from the browser (and also push to talk buttons from the browser, even if another app is focused). On the audio side, with HTML5 is there any way of taking audio input from the browser to compress and send to our servers? I know with Flash such is possible, but we're trying to avoid flash for mobile compatibility and generally looking toward the future.

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• Can I join between two MySQL tables stores on separate machines?

  - by CuriousCoder

  I have a relatively light query that needs information from a local MySQL table along with another MySQL table which is stored on a physically separate machine (on the same network). I'm keen to avoid setting up replication just to facilitate this light query that only needs executed once a day. Is there any way that I can join with a table on a remote machine using one query? Or run a SELECT INTO into a local table. Notes I'm using C# & .NET 4.

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• Can I change the database server and database a report is pointing to dynamically?

  - by Randy Minder

  I have a Crystal 2008 report that will be deployed to an InfoView server. There are four different databases the user might want to execute the report against. Each of the four databases have exactly the same schema. Only the data in each is different. Each database corresponds to a plant we have around the world. Instead of creating four different reports (each one connected to one of the four databases), am I able to dynamically change the server/database the report hits based on a value the user enters into a parameter? I'm really trying to avoid having to create four identical reports except for the database connection on each. If this isn't possible, how do developers typically deal with this sort of scenario? I would imagine it's fairly common. Thanks very much.

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• Strategy for Storing Multiple Nullable Booleans in SQL

  - by Eric J.

  I have an object (happens to be C#) with about 20 properties that are nullable booleans. There will be perhaps a few million such objects persisted to a SQL database (currently SQL Server 2008 R2, but MySQL may need to be supported in the future). The instances themselves are relatively large because they contain about a paragraph of text as well as some other unrelated properties. For a given object instance, most of the properties will be null most of the time. When users search for instances of such objects, they will select perhaps 1-3 of the nullable boolean properties and search for instances where at least one of those 1-3 properties is non-null (OR search). My first thought is to persist the object to a single table with nullable BIT columns representing the nullable boolean properties. However, this strategy will require one index per BIT column to avoid performing a table scan when searching. Further, each index would not be particularly selective since there are only three possible values per index. Is there a better way to approach this problem?

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• [Symfony] Admin generator and i18n

  - by David

  I have read lots of questions about i18n, but I haven't found any about performance. I have a simple backend app listing the contents of an ads table. These ads have a category, that is translated in some languages (it's defined as i18n in the Doctrine schema). So, when I add a "table_method" in my generator.yml to include de Category table, it reduces the number of queries, but there are yet some of them referencing i18n translation tables. So, if I add the category Translation table to the query, it reduces even more the queries BUT it increases the processing time considerably. Why this time penalty? Just because of the translation table? And why isn't the filter using this method to avoid so many translation queries as well? I mean, if I want to filter by category, it is making one query per category to include the translation table. Why??

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• bitfield mask calculation macro

  - by Aidan Cully

  We have a set of C macros, here, for using the preprocessor to do bitfield operations, and we run into warnings when attempting to use these macros in visual studio. The problem can be demonstrated very easily: #define BITFIELD_WIDTHMASK(Width) \ ((Width) >= 32 ? ~0x0ul : (1ul << (Width)) - 1) unsigned long foo(void) { return BITFIELD_WIDTHMASK(32); } Compiling this with MSVC yields the warning: test.c(12) : warning C4293: '<<' : shift count negative or too big, undefined behavior This isn't a behavior problem - the << operator won't be used in this case, and that should be detected at compile time. But does anyone have any suggestions about how to rewrite the macro to avoid the warning? Or, failing that, how to redesign the macro interface for this? Thanks in advance

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• does it make sense to send password information during email communication from websites

  - by Samuel

  Most of the online sites on registration do send a link to activate the site and on any further correspondence with the end user they provide information about the site and also provide the login credentials with password in clear text (as given below) Username - [email protected] Password - mysecretpassword What would you do in such a case? From a usability perspective does it make sense to send the password information in clear text or should you just avoid sending this information. I was under the impression that most of the passwords are MD5 hashed before storing in the database and hence the service provider will not have any access to clear text passwords, is this a security violation?

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• Paging Recordsets from SQL Serverside

  - by Jonno

  I've been banging my head off this one for a while. I want to call 1k records from a SQL database and page them per 100. In classic ASP (where I'm moving from) this was dead easy to do with ADODB but with VB using ADO.net I can't find a single way that doesn't involve stored procs (which I want to avoid for now). It seems really stupid to call all 1k and sort it programmatically. Edit: It's SQL Server 2005 / .net 4.0 / Visual Studio 2010. Edit 2: Just to reiterate, I have Googled extensively and don't want to use stored procedures. There are many ways to get paged data but everything I see involves paging the data in the program rather than from the server.

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• How to fix this python error? RuntimeError: dictionary changed size during iteration

  - by aF

  Hello, it gives me this error: Exception in thread Thread-163: Traceback (most recent call last): File "C:\Python26\lib\threading.py", line 532, in __bootstrap_inner self.run() File "C:\Python26\lib\threading.py", line 736, in run self.function(*self.args, **self.kwargs) File "C:\Users\Public\SoundLog\Code\Código Python\SoundLog\SoundLog.py", line 337, in getInfo self.data1 = copy.deepcopy(Auxiliar.DataCollection.getInfo(1)) File "C:\Python26\lib\copy.py", line 162, in deepcopy y = copier(x, memo) File "C:\Python26\lib\copy.py", line 254, in _deepcopy_dict for key, value in x.iteritems(): RuntimeError: dictionary changed size during iteration while executing my python program. How can I avoid this to happen? Thanks in advance ;)

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• Client / Server application for Video BroadCasting on LAN

  - by jbl

  I m much of a newbie to client/server applications and networking.I am currently starting up a project in which we are planning to create an application or something like a website accessible only to clients in that LAN network.We want the server to upload videos so that the clients can view them whenever they want.Also the clients can upload videos.Also we want some kind of registration to provide authentication to avoid bogus videos.Also additional features that can be added on later like comment section,ratings,Groups etc. Basically what we want is to build mini-youtube but with one major difference , we want the application to be LAN based. This is the idea behind the project.But we dont know where to start from as we are new to this stuff and also we have like 1 year to work on the project.Please guide me as to what all softwares i'll be needing to get this working !

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• Keeping track of dirty blocks on a block device

  - by mikeY

  I'm looking for a way to keep track of what blocks on a block device are modified after a point in time. How I eventually want to use this for is to keep two 2TB disks in sync, one which only comes online (connected through USB) once a month. Without knowing what blocks have been modified, I have to go through the whole 2TB every time. I'm using a recent GNU/Linux OS and have C and Python experience. I'm hoping to avoid writing kernel level code as I don't have any experience in that area whatsoever. My current theory is that there should be some hooks somewhere where my code can get called when a disk flush is performed. Any ideas?

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• What is faster: multiple `send`s or using buffering?

  - by dauerbaustelle

  I'm playing around with sockets in C/Python and I wonder what is the most efficient way to send headers from a Python dictionary to the client socket. My ideas: use a send call for every header. Pros: No memory allocation needed. Cons: many send calls -- probably error prone; error management should be rather complicated use a buffer. Pros: one send call, error checking a lot easier. Cons: Need a buffer :-) malloc/realloc should be rather slow and using a (too) big buffer to avoid realloc calls wastes memory. Any tips for me? Thanks :-)

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• What is the effect on record size of reordering columns in PostgreSQL?

  - by Summer

  Since Postgres can only add columns at the end of tables, I end up re-ordering by adding new columns at the end of the table, setting them equal to existing columns, and then dropping the original columns. So, what does PostgreSQL do with the memory that's freed by dropped columns? Does it automatically re-use the memory, so a single record consumes the same amount of space as it did before? But that would require a re-write of the whole table, so to avoid that, does it just keep a bunch of blank space around in each record? Thanks! ~S

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• Importing a spreadsheet, but having trouble.

  - by Chris Phelps

  I have a form that allows a user to import a spreadsheet. This spreadsheet is generally static when it comes to column headers, but now the users want to be able to include an optional column (called Notes). My code crashes when I try to read the column from the spreadsheet if it doesn't exist. Dim objCommand As New OleDbCommand() objCommand = ExcelConnection() 'function that opens spreadsheet and returns objCommand Dim reader As OleDbDataReader reader = objCommand.ExecuteReader() While reader.Read() Dim Employee As String = Convert.ToString(reader("User")) Dim SerialNUM As String = Convert.ToString(reader("serialno")) **Dim Notes As String = Convert.ToString(reader("notes"))** If the spreadsheet contains a Notes column, all goes well. If not, crash. How can I check to see if the Notes column exists in the spreadsheet to avoid the crash?

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• What is the ISO C++ way to directly define a conversion function to reference to array?

  - by ben

  According to the standard, a conversion function has a function-id operator conversion-type-id, which would look like, say, operator char(&)[4] I believe. But I cannot figure out where to put the function parameter list. gcc does not accept either of operator char(&())[4] or operator char(&)[4]() or anything I can think of. Now, gcc seems to accept (&operator char ())[4] but clang does not, and I am inclined to not either, since it does not seem to fit the grammar as I understand it. I do not want to use a typedef because I want to avoid polluting the namespace with it.

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• R- delete rows in multiple columns by unique number

  - by Vincent Moriarty

  Given data like this C1<-c(3,-999.000,4,4,5) C2<-c(3,7,3,4,5) C3<-c(5,4,3,6,-999.000) DF<-data.frame(ID=c("A","B","C","D","E"),C1=C1,C2=C2,C3=C3) How do I go about removing the -999.000 data in all of the columns I know this works per column DF2<-DF[!(DF$C1==-999.000 | DF$C2==-999.000 | DF$C3==-999.000),] But I'd like to avoid referencing each column. I am thinking there is an easy way to reference all of the columns in a particular data frame aka: DF3<-DF[!(DF[,]==-999.000),] or DF3<-DF[!(DF[,(2:4)]==-999.000),] but obviously these do not work And out of curiosity, bonus points if you can me why I need that last comma before the ending square bracket as in: ==-999.000),]

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• How to make a file with .pt extension, with xml syntax highlighting and vim's plugin snipmate load p

  - by Somebody still uses you MS-DOS

  I have the following in my .vimrc: au BufNewFile,BufRead *.pt set filetype=xml This is needed because although I'm editing a file with *.pt extension, it's indeed a valid xml file: setting the filetype like this I can have syntax highlighting. I'm using vim's snipmate plugin, and tried to create pt.snippets to specific needs since these files are Zope Page Templates (ZPT with TAL). Now, I have a problem: I don't want to create these snippets in xml.snippets, since they aren't really generic xml snippets, but my *.pt files are set to xml, so when I define my pt snippets they aren't loaded unless I run :set filetype=pt on my pt file on vim - but then I lose syntax highlighting. I would like to be able to have a pt file, with xml syntax highlighting, to be able to load a pt.snippets file from snipmate. How can I do it? (I would like to avoid putting my snippets in a generic snippet file, I would like it to be present only in pt.snippets to be easier to maintain.)

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