Search Results

Search found 5429 results on 218 pages for 'smart pointers'.

Page 146/218 | < Previous Page | 142 143 144 145 146 147 148 149 150 151 152 153  | Next Page >

• Function calls in virtual machine killing performance

  - by GenTiradentes

  I wrote a virtual machine in C, which has a call table populated by pointers to functions that provide the functionality of the VM's opcodes. When the virtual machine is run, it first interprets a program, creating an array of indexes corresponding to the appropriate function in the call table for the opcode provided. It then loops through the array, calling each function until it reaches the end. Each instruction is extremely small, typically one line. Perfect for inlining. The problem is that the compiler doesn't know when any of the virtual machine's instructions are going to be called, as it's decided at runtime, so it can't inline them. The overhead of function calls and argument passing is killing the performance of my VM. Any ideas on how to get around this?

  Read the article

• New to Drupal -- how should I create a main page with a mix of dynamic and static content?

  - by Erode

  I apologize for the terribly basic question but I'm not even a particularly adept web dev. I've read that Drupal is great if you know exactly what you want to do (then the API is handy) but I don't even know what I need yet. That is what I am hoping to gain from this discussion. I want a main content page which has a fancy content slider (using jQuery or something) which will be a selector for showing some basic information on these 2 or 3 subjects. I'm stuck on where I should be writing this mix of markup. In the template? Create "content" through a content type? Since there's a fair share of CSS and markup required to do this, I don't know if I can do that through the "basic page" content type that was there. I'm looking for pointers that can teach me how I would become aware of what Drupal can and can not do. Thanks for reading, let me know if I need to clarify anything.

  Read the article

• What are the things Java got right?

  - by hamletdarcy

  What are the things that Java (the language and platform) got categorically right? In other words, what things are more recent programming languages preserving and carrying forward? Some easy answer are: garbage collection, a VM, lack of pointers, classloaders, reflection(?) What about language based answers? Please don't list the things Java did wrong, just right. (note by Mark Harrison) This is an interesting and useful question, especially for those of us who don't use java regularly. I'm voting for reopening. Please don't close as argumentative, as it doesn't seem to be causing any arguments.

  Read the article

• Is it legal for a C++ reference to be NULL?

  - by BCS

  A while back I ran into a bug the looked something like this: void fn(int &i) { printf(&i == NULL ? "NULL\n" : "!NULL\n"); } int main() { int i; int *ip = NULL; fn(i); // prints !NULL fn(*ip); // prints NULL return 0; } More recently, I ran into this comment about C++ references: [References arguments make] it clear, unlike with pointers, that NULL is not a possible value. But, as show above, NULL is a possible value. So where is the error? In the language spec? (Unlikely.) Is the compiler in error for allowing that? Is that coding guide in error (or a little ambiguous)? Or am I just wandering into the minefield known as undefined behavior?

  Read the article

• In game programming are global variables bad?

  - by Joe.F

  I know my gut reaction to global variables is "badd!" but in the two game development courses I've taken at my college globals were used extensively, and now in the DirectX 9 game programming tutorial I am using (www.directxtutorial.com) I'm being told globals are okay in game programming ...? The site also recommends using only structs if you can when doing game programming to help keep things simple. I'm really confused on this issue, and all the research I've been trying to do is very confusing. I realize there are issues when using global variables (threading issues, they make code harder to maintain, the state of them is hard to track etc) but also there is a cost associated with not using globals, I'd have to pass a loooot of information around very often which can be confusing and I imagine time-costing, although I guess pointers would speed the process up (this is my first time writing a game in C++.) Anyway, I realize there is probably no "right" or "wrong" answer here since both ways work, but I want my code to be as proper as I can so any input would be good, thank you very much!

  Read the article

• Why this code does not do what I mean?

  - by Mike

  $w = 'self-powering'; %h = (self => 'self', power => 'pau?', ); if ($w =~ /(\w+)-(\w+)ing$/ && $1~~%h && $2~~%h && $h{$2}=~/?$/) { $p = $h{$1}.$h{$2}.'ri?'; print "$w:"," [","$p","] "; } I expect the output to be self-powering: selfpau?ri? But what I get is: self-powering: [ri?] My guess is something's wrong with the code $h{$2}=~/?$/ It seems that when I use $h{$2}!~/?$/ Perl will do what I mean but why I can't get "self-powering: selfpau?ri?"? What am I doing wrong? Any ideas? Thanks as always for any comments/suggestions/pointers :)

  Read the article

• Listing C/C++ functions (Code analysis in Unix)

  - by Jond

  Whether we're maintaining unfamiliar code or checking out the implementation details of an Apache module it can help if we can quickly traverse the code and build up an overview of what we're looking at. Grep serves most of my daily needs but there are some cases where it just wont do. Here's a common example of how it can help. To find the definition of a PHP function I'm interested in I can type this at the command line: grep -r "function myfunc" . This could be adapted very quickly to C or C++ if we know the return type, but things become more complicated if, say, I want to list every method that my class provides: grep "function " ./src/mine.class.php Since there's no single keyword that denotes a function or method in C++ and because it's generally more complex syntax, I think I'd need some kind of static code analysis tool, smart use of the C Preprocessor or blind faith the coder followed strict code guidelines (# of whitespace, position of curlies etc) to get these sorts of results. What would you recommend? p.s. be nice, this is my first post ;-) :p

  Read the article

• Reading bytes from a text file that has the form of machine code in C?

  - by rashid

  I have a text file with machine code in this form: B2 0A 05 B2 1A 01 B3 08 00 17 B2 09 18 where an instruction has this format: OP Mode Operand Note: Operand could be 1 or 2 bytes. Where:(example) OP = B2 Mode = 0A Operand = 05 How can I read the bytes in a variable? As shown in the above example. When i read the file I get individual characters. I have an array of pointers where I read individual line, but still cannot solve the problem of reading a byte. Any ideas,suggestions. I hope I am not confusing anyone here. Thank you.

  Read the article

• How to change size of STL container in C++

  - by Jaime Pardos

  I have a piece of performance critical code written with pointers and dynamic memory. I would like to rewrite it with STL containers, but I'm a bit concerned with performance. Is there a way to increase the size of a container without initializing the data? For example, instead of doing ptr = new BYTE[x]; I want to do something like vec.insert(vec.begin(), x, 0); However this initializes every byte to 0. Isn't there a way to just make the vector grow? I know about reserve() but it just allocates memory, it doesn't change the size of the vector, and doesn't allows me to access it until I have inserted valid data. Thank you everyone.

  Read the article

• Finding PHP dependencies

  - by JW

  Are there any tools that can list the names of classes used by a PHP file? For example, if I ran it on this file: <? class Test { public function __construct(Obj1 $x) { $y = new Obj2(); $str = "Obj3"; $z = new $str(); } } ?> it would report "Obj1" and "Obj2". If it were really smart it might report "Obj3" as well, but that's not essential. I'm trying to package up some code, and I want some help making sure that I didn't miss any dependencies. There's something called PHP_Depend, which can graph the number of dependencies, but can't report what they are.

  Read the article

• how to go the middle of the singularly linked list in one iteration?

  - by u3050

  Recently I have been asked one question that in a singularly linked list how do we go to the middle of the list in one iteration. A --> B --> C --> D (even nodes) for this it should return address which points to B A --> B --> C (odd nodes) for this also it should return address which points to B There is one solution of taking two pointers one moves one time and other moves two times but it does not seem working here LinkedList p1,p2; while(p2.next != null) { p1 = p1.next; p2 = p2.next.next; } System.out.print("middle of the node" + p1.data); //This does not give accurate result in odd and even Please help if anyone has did this before.

  Read the article

• Sorting 1000-2000 elements with many cache misses

  - by Soylent Graham

  I have an array of 1000-2000 elements which are pointers to objects. I want to keep my array sorted and obviously I want to do this as quick as possible. They are sorted by a member and not allocated contiguously so assume a cache miss whenever I access the sort-by member. Currently I'm sorting on-demand rather than on-add, but because of the cache misses and [presumably] non-inlining of the member access the inner loop of my quick sort is slow. I'm doing tests and trying things now, (and see what the actual bottleneck is) but can anyone recommend a good alternative to speeding this up? Should I do an insert-sort instead of quicksorting on-demand, or should I try and change my model to make the elements contigious and reduce cache misses? OR, is there a sort algorithm I've not come accross which is good for data that is going to cache miss?

  Read the article

• How to insert into a table with just one IDENTITY column (SQL Server CE)

  - by Hei

  Hello I am trying to insert a value in a one IDENTITY column Table in SQL Server CE 3.5. I Tried the following: INSERT Target DEFAULT VALUES INSERT Target (ID) VALUES (DEFAULT) INSERT Target (ID) VALUES () But none of them worked. This is the SQL command I used to create the table (Using SQL Server Management Studio): CREATE TABLE Target( ID int NOT NULL IDENTITY (1, 1) PRIMARY KEY ); Microsoft help site (http://msdn.microsoft.com/en-us/library/ms174633%28SQL.90%29.aspx) mentions that DEFAULT values are not valid for identity columns however they do not mention any alternative. They mention something about uniqueidentifier and ROWGUID but I have not been able to make it work. I would appreciate any pointers on how to solve this problem or links to documentation about valid sql commands for sql server CE. Thank you

  Read the article

• MySQL "NULL" questions

  - by Camran

  I have a table with several columns. Sometimes some of these column fields may be empty (ie. I won't use them in some cases). My questions: Would it be smart to set them to NULL in phpmyadmin? What does the "NULL" property actually do? Would I gain anything at all by setting them to NULL? Is it possible to use a NULL field the same way even though it is set to null?

  Read the article

• Force an object to be allocated on the heap

  - by Warren Seine

  A C++ class I'm writing uses shared_from_this() to return a valid boost::shared_ptr<>. Besides, I don't want to manage memory for this kind of object. At the moment, I'm not restricting the way the user allocates the object, which causes an error if shared_from_this() is called on a stack-allocated object. I'd like to force the object to be allocated with new and managed by a smart pointer, no matter how the user declares it. I thought it could be done through a proxy or an overloaded new operator, but I can't find a proper way of doing that. Is there a common design pattern for such usage? If it's not possible, how can I test it at compile time?

  Read the article

• Combining packages from different projects into a single project in eclipse

  - by primal

  Hi, As part of the Android application I am developing in eclipse, I need to combine two packages from different projects into a single project. I tried copying the files in the package of the second project under the src folder of the first folder and copied other files required for second package into the res folder of the first project. But the auto-generated Java files i.e R.java doesn't get updated on copying. I tried right clicking on the project and clicking on Android Tools - Fix Project Properties. But nothing changed. Any pointers on what I am doing wrong much be appreciated.

  Read the article

• Editable CATextLayer?

  - by Ron

  I have several CATextLayers. When I doubleclick one of them, I want to be able to edit it's string. Think of text as it's handled in Keynote or many other apps. Any ideas? I thought of putting an editable textfield right in front of the layer and then dismiss it on enter, but I didn't get far. :-( I target Mac OS X 10.5 with Objective-C 2.0 and Garbage Collection. Any help or pointers would be greatly appreciated. Thanks in advance!!

  Read the article

• "Voice trigger" detection

  - by sehugg

  I have a voice application that would be much-improved if there was the ability to use a "trigger word" to start recording audio. I don't need a full speech-text engine, just the ability to reliably/efficiently detect the trigger word. I am wondering if there are any specialized speech engines that support this specific use case, or any libraries/methods to developing such a single-purpose detection engine. Ideally I'd like it to work in noisy environments, but it can be trained for a single user's voice. Pointers to research papers / topics would also be appreciated so I know what to ask for.

  Read the article

• using JDBC with persistence.xml

  - by moshe shamy

  I am building a framework that manage the access to the database. the framework getting tasks from the user and handle a connection pooling that manage the access to the database. the user just send me SQL commands. One of the feature that i would like to support is working with JPA, in this case i will provide entity manager. in some cases i would like to provide JDBC access as well as JPA access. the arguments for the database are written in XML file. so for JPA i need to write the property in persistence.xml so it will be not so smart to write again the same arguments for JDBC. do you know if i can get the arguments of the database from persistence.xml, do you know if there is a source code that do it. or should i parse persistence.xml by myself?

  Read the article

• How can a class's memory-allocated address be determined from within the contructor?

  - by Jim Fell

  Is it possible to get the memory-allocated address of a newly instantiated class from within that class's constructor during execution of said constructor? I am developing a linked list wherein multiple classes have multiple pointers to like classes. Each time a new class instantiates, it needs to check its parent's list to make sure it is included. If I try to do something like this: MyClass() // contructor { extern MyClass * pParent; for ( int i = 0; i < max; i++ ) { pParent->rels[i] == &MyClass; // error } } I get this error: error C2275: 'namespace::MyClass' : illegal use of this type as an expression Any thoughts or suggestions would be appreciated. Thanks.

  Read the article

• Rapid Web Application Development ASP.net vs. Open Source Platforms

  - by Yaaqov

  Good morning - I'm an intermediate-level developer who wants to build on online data-driven app (CRUD with a few calculations and basic HTML form inputs, nothing fancy) that keeps track of user sessions, and looks "professional" (or at least not "homemade"). I'm looking to development something with the look-and-feel that users get from sites like: http://www.datamasher.org/ http://www.thisweknow.org/ (About page says it was made with Ruby on Rails, which I'm unfamiliar with) (stackoverflow.com) Any pointers on whether I should just go the Miscrosoft route, and develop in ASP.net with WebForms, or if there's a quick qay to do this kind of development (with a WYSIWYG environment) on an open-source platform? I'm willing to learn, if it's somethat I can use to quickly drag/drop, add code, and publish online. Templates would be a plus, too. I apologize is the question seems a bit vague.

  Read the article

• Passing around objects to network packet handlers ?

  - by xeross

  Hey, I've been writing a networking server for a while now in C++ and have come to the stage to start looking for a way to properly and easily handle all packets. I am so far that I can figure out what kind of packet it is, but now I need to figure out how to get the needed data to the handler functions. I had the following in mind: Have a map of function pointers with the opcode as key and the function pointer as value Have all these functions have 2 arguments, packet and ObjectAccessor ObjectAccessor class contains various functions to fetch various items such as users and alike Perhaps pass the user's guid too so we can fetch it from the objectaccessor I'd like to know the various implementations others have come up with, so please comment on this idea and reply with your own implementations. Thanks, Xeross

  Read the article

• Reaplaceing the Import Table in PE file by standart LoadLibrary...

  - by user308368

  Hello. I have an executable (PE) file that load a dll file as represented in the Import table... let say: PEFile.exe Modules.dll my question is how can i remove Modules.dll's import_descriptor from the imports and do its work by loadLibrary without the rely on the import table and without destroy the file???... My bigger problem his i could not understand exactly how the Import thing works... after the loader read the information he needs to do the import's thing, i believe he use the LoadLibrary, GetProcAddress APIs... but i couldn't understated what he doing with the pointers he get... he putting them somewhere in memory... and then what just call them?!? all the papers i found in the net explain the structure of the import table, but i didn't found a paper that explain how it is really work and get used... i hope you cold understand my Gibberish English... Thank you!

  Read the article

• Web Application - Authentication / Login Framework

  - by user456563

  This is a very simple, probably a most asked question and frequently developed as part of any web application. Say I'm planning to build a web application and some of the functional requirements include (apart from the usual hard hitting security reqs), - Need to have users sign up for a new account profile - Authenticate user using the native app authentication / Facebook or Google or Yahoo or OpenId login - Allow lost password retrieval - Session handling needs Is there an out of the box frameworks (Drupal, Liferay??) that I can use to wrap my application which can be a bunch of JSP's or HTML's with JS? I know I'm asking a very simple and maybe a naive question. But this is a topic every web developer guru will go thru. Any help, advise and pointers much appreciated.

  Read the article

• Is it good practice to avoid declaring a pointer to BOOL type in objective C?

  - by Krishnan

  I read this question in stackoverflow. The excerpt answer provided by bbum is below: The problem isn't the assignment, it is much more likely that you declared your instance variable to be BOOL *initialBroadcast;. There is no reason to declare the instance variable to be a pointer (at least not unless you really do need a C array of BOOLs).. Remove the * from the declaration. 1.Is there anything wrong in using a pointer variable even when I do not have to maintain an array of BOOLs? 2.I think even if avoiding them a good practice, it is not specific to objective-C and applies to all programming languages which has pointers. Please answer my questions.

  Read the article

< Previous Page | 142 143 144 145 146 147 148 149 150 151 152 153  | Next Page >