Search Results

Search found 18592 results on 744 pages for 'basic unix commands'.

Page 644/744 | < Previous Page | 640 641 642 643 644 645 646 647 648 649 650 651  | Next Page >

• .each or search function, how can I make use of those?

  - by Noor

  I have a ul list, with 10 items, and I have a label that displays the selected li text. When I click a button, I need to check the label, versus all the list items to find the matching one, when it finds that I need to assign the corresponding number. I.e. list: Messi Cristiano Zlatan hidden values of list items: www.messi.com www.cronaldo.com www.ibra.com label: Zlatan script (thought)procces: get label text, search list for matching string, get the value of that string. (and if someone could point me in a direction to learn these basic(?) stuff. tried to be as specific as possible, thanks guys! edit: really sorry for not being clear. the li's are all getting a class dynamically (.listitem). the links can be stored in an array or in a hidden field (or other ul thats hidden) it doesn't really matter where the links are.. $('.listitem').click(function() { $("#elname").text($(this).text()); $("#such").attr("href", $(this).attr('value')); }); I was trying that with the li's having values but I realized that li's can't have values.. thanks again!

  Read the article

• Why are references compacted inside Perl lists?

  - by parkan

  Putting a precompiled regex inside two different hashes referenced in a list: my @list = (); my $regex = qr/ABC/; push @list, { 'one' => $regex }; push @list, { 'two' => $regex }; use Data::Dumper; print Dumper(\@list); I'd expect: $VAR1 = [ { 'one' => qr/(?-xism:ABC)/ }, { 'two' => qr/(?-xism:ABC)/ } ]; But instead we get a circular reference: $VAR1 = [ { 'one' => qr/(?-xism:ABC)/ }, { 'two' => $VAR1->[0]{'one'} } ]; This will happen with indefinitely nested hash references and shallowly copied $regex. I'm assuming the basic reason is that precompiled regexes are actually references, and references inside the same list structure are compacted as an optimization (\$scalar behaves the same way). I don't entirely see the utility of doing this (presumably a reference to a reference has the same memory footprint), but maybe there's a reason based on the internal representation Is this the correct behavior? Can I stop it from happening? Aside from probably making GC more difficult, these circular structures create pretty serious headaches. For example, iterating over a list of queries that may sometimes contain the same regular expression will crash the MongoDB driver with a nasty segfault (see https://rt.cpan.org/Public/Bug/Display.html?id=58500)

  Read the article

• UIViewController memory management

  - by jAmi

  Hi I have a very basic issue of memory management with my UIViewController (or any other object that I create); The problem is that in Instruments my Object allocation graph is always rising even though I am calling release on then assigning them nil. I have 2 UIViewController sub-classes each initializing with a NIB; I add the first ViewController to the main window like [window addSubView:first.view]; Then in my first ViewController nib file I have a Button which loads the second ViewController like : -(IBAction)loadSecondView{ if(second!=nil){ //second is set as an iVar and @property (nonatomic, retain)ViewController2* sceond; [second release]; second=nil; } second=[[ViewController2* second]initWithNibName:@"ViewController2" bundle:nil]; [self.view addSubView:second.view]; } In my (second) ViewController2 i have a button with an action method -(IBAction) removeSecond{ [self.view removeFromSuperView]; } Please let me know if the above scheme works in a managed way for memory...? In Instruments It does not show release of any allocation and keeps the bar status graph keeps on rising.

  Read the article

• XSLT line counter - is it that hard?

  - by Mr AH

  I have cheated every time I've needed to do a line count in XSLT by using JScript, but in this case I can't do that. I simply want to write out a line counter throughout an output file. This basic example has a simple solution: <xsl:for-each select="Records/Record"> <xsl:value-of select="position()"/> </xsl:for-each> Output would be: 1 2 3 4 etc... But what if the structure is more complex with nested foreach's : <xsl:for-each select="Records/Record"> <xsl:value-of select="position()"/> <xsl:for-each select="Records/Record"> <xsl:value-of select="position()"/> </xsl:for-each> </xsl:for-each> Here, the inner foreach would just reset the counter (so you get 1, 1, 2, 3, 2, 1, 2, 3, 1, 2 etc). Does anyone know how I can output the position in the file (ie. a line count)?

  Read the article

• What can cause my code to run slower when the server JIT is activated?

  - by durandai

  I am doing some optimizations on an MPEG decoder. To ensure my optimizations aren't breaking anything I have a test suite that benchmarks the entire codebase (both optimized and original) as well as verifying that they both produce identical results (basically just feeding a couple of different streams through the decoder and crc32 the outputs). When using the "-server" option with the Sun 1.6.0_18, the test suite runs about 12% slower on the optimized version after warmup (in comparison to the default "-client" setting), while the original codebase gains a good boost running about twice as fast as in client mode. While at first this seemed to be simply a warmup issue to me, I added a loop to repeat the entire test suite multiple times. Then execution times become constant for each pass starting at the 3rd iteration of the test, still the optimized version stays 12% slower than in the client mode. I am also pretty sure its not a garbage collection issue, since the code involves absolutely no object allocations after startup. The code consists mainly of some bit manipulation operations (stream decoding) and lots of basic floating math (generating PCM audio). The only JDK classes involved are ByteArrayInputStream (feeds the stream to the test and excluding disk IO from the tests) and CRC32 (to verify the result). I also observed the same behaviour with Sun JDK 1.7.0_b98 (only that ist 15% instead of 12% there). Oh, and the tests were all done on the same machine (single core) with no other applications running (WinXP). While there is some inevitable variation on the measured execution times (using System.nanoTime btw), the variation between different test runs with the same settings never exceeded 2%, usually less than 1% (after warmup), so I conclude the effect is real and not purely induced by the measuring mechanism/machine. Are there any known coding patterns that perform worse on the server JIT? Failing that, what options are available to "peek" under the hood and observe what the JIT is doing there?

  Read the article

• Sorting out POCO, Repository Pattern, Unit of Work, and ORM

  - by CoffeeAddict

  I'm reading a crapload on all these subjects: POCO Repository Pattern Unit of work Using an ORM mapper ok I see the basic definitions of each in books, etc. but I can't visualize this all together. Meaning an example structure (DL, BL, PL). So what, you have your DL objects that contain your CRUD methods, then your BL objects which are "mapped" using an ORM back to your DL objects? What about DTOs...they're your DL objects right? I'm confused. Can anyone really explain all this together or send me example code? I'm just trying to put this together. I am determining whether to go LINQ to SQL or EF 4 (not sure about NHibrernate yet). Just not getting the concepts as in physical layers and code layers here and what each type of object contains (just properties for DTOs, and CRUDs for your core DL classes that match the table fields???). I just need some guidance here. I'm reading Fowler's books and starting to read Evans but just not all there yet.

  Read the article

• SQL Server 2005 Import from Excel

  - by user327045

  I'd like to know what my best option would be to import data from an excel file on a weekly or monthly basis. At first, I thought I would use SSIS, but after much struggle with seemingly simple tasks, I'm starting to rethink my plan. Would it be better/easier to just write the SQL by hand or use the services of an SSIS package? The basic process will be as follows: A separate process will download an .xls file to a local fileshare. The xls file will have a filename like: 'myfilename MON YY'. I will need to read the month and year from the the filename, reformat it to a sql date and then query a DimDate table to find the corresponding date key. For each row (after the first 2 header rows), insert the data with the date key, unless the row is a total row, then ignore. Here are some of the issues I've been encountering with SSIS: I can parse the date string from a flat file datasource, but can't seem to do it with an excel data source. Also, once parsed, i cannot seem to convert the string to a date in order to perform the lookup for the date key. For example, I want to do something like this: select DateKey from DimDate where ActualDate = convert(datetime, '01-' + 'JAN-10', 120) but i don't think it is possible to use the 'convert' or 'datetime' keywords in an expression builder. I have been also unable to find where I can edit the SQL to ignore the first 2 rows of data. I'm very skeptical of using SSIS because it seems like a Kludgy way of doing something that can probably be accomplished more efficiently writing the SQL yourself, but I may be forced to use SSIS. Thoughts?

  Read the article

• How to implement generic callbacks in C++

  - by Kylotan

  Forgive my ignorance in asking this basic question but I've become so used to using Python where this sort of thing is trivial that I've completely forgotten how I would attempt this in C++. I want to be able to pass a callback to a function that performs a slow process in the background, and have it called later when the process is complete. This callback could be a free function, a static function, or a member function. I'd also like to be able to inject some arbitrary arguments in there for context. (ie. Implementing a very poor man's coroutine, in a way.) On top of that, this function will always take a std::string, which is the output of the process. I don't mind if the position of this argument in the final callback parameter list is fixed. I get the feeling that the answer will involve boost::bind and boost::function but I can't work out the precise invocations that would be necessary in order to create arbitrary callables (while currying them to just take a single string), store them in the background process, and invoke the callable correctly with the string parameter.

  Read the article

• jQuery rotator not rotating properly - too much recursion

  - by Matt Nathanson

  I've built a custom jQuery rotator using just basic animation to rotate the 3 Divs (images). I've built the function and then reinitiate the function using it as a call back. Here's the code: function ImageRotate() { var CurrentFeature = "#container" + featureNumber; $(CurrentFeature).stop(false, true).delay(4500).animate({'top' : '330px'}, 3000); var featureNumber2 = featureNumber-1; if ( featureNumber == 1) {featureNumber2=3} var CurrentFeature2 = "#container" + featureNumber2; $(CurrentFeature2).stop(false, true).delay(4500).animate({'top' : '0px'}, 3000); $('#container2').stop(false, true).delay(4500).animate({'top' : '-330px'}, 25); var featureNumber3 = featureNumber+1; if ( featureNumber == 3){featureNumber3=1} var CurrentFeature3 = "#container" + featureNumber3; $(CurrentFeature3).stop(false, true).delay(7500).animate({'top' : '0px'}, 3000); $(CurrentFeature2).stop(false, true).delay(4500).animate({'top' : '330px'}, 3000); $(CurrentFeature).stop(false, true).delay(4500).animate({'top' : '-330px'}, 25); if (featureNumber ==1) {featureNumber=3} else{featureNumber--}; $(CurrentFeature).stop(false, true).delay(7500).animate({'top' : '0px'}, 3000); $(CurrentFeature3).stop(false, true).delay(4500).animate({'top' : '330px'}, 3000); $(CurrentFeature2).stop(false, false).delay(4500).animate({'top' : '-330px'}, 25,ImageRotate()); }; It's worth noting that when calling the function again I also tried making another function called ImageRotate2(); and it did the same thing. It loops, but i get all sorts of funkiness. Edit: I've also tried some answers in the replies and they both leave me with recursion errors each second.

  Read the article

• How to call a function from another class file

  - by Guy Parker

  I am very familiar with writing VB based applications but am new to Xcode (and Objective C). I have gone through numerous tutorials on the web and understand the basics and how to interact with Interface Builder etc. However, I am really struggling with some basic concepts of the C language and would be grateful for any help you can offer. Heres my problem… I have a simple iphone app which has a view controller (FirstViewController) and a subview (SecondViewController) with associated header and class files. In the FirstViewController.m have a function defined @implementation FirstViewController (void) writeToServer:(const uint8_t ) buf { [oStream write:buf maxLength:strlen((char)buf)]; } It doesn't really matter what the function is. I want to use this function in my SecondViewController, so in SecondViewController.m I import FirstViewController.h import "SecondViewController.h" import "FirstViewController.h" @implementation SecondViewController -(IBAction) SetButton: (id) sender { NSString *s = [@"Fill:" stringByAppendingString: FillLevelValue.text]; NSString *strToSend = [s stringByAppendingString: @":"]; const uint8_t *str = (uint8_t *) [strToSend cStringUsingEncoding:NSASCIIStringEncoding]; FillLevelValue.text = strToSend; [FirstViewController writeToServer:str]; } This last line is where my problem is. XCode tells me that FirstViewController may not respond to writeToServer. And when I try to run the application it crashes when this function is called. I guess I don't fully understand how to share functions and more importantly, the relationship between classes. In an ideal world I would create a global class to place my functions in and call them as required. Any advice gratefully received.

  Read the article

• Updating ToolStripProgressBar and ToolStripStatusLabel along with with an action

  - by TChristian

  In a Windows Form, I have a search box that fires an event to search a remote database and display some results. The query is pretty fast, usually just a fraction of a second, but in case the delay is noticeable there is a progress bar and label in the form's status bar. When the user clicks "Search" the status label should appear and the progress bar show some progress. Then when the result comes back the label should disappear and the progress bar should be full. Pretty basic response. The problem is, I can't get those actions to happen in that order. Using the code below, I click "Search", nothing happens until the results are displayed, and then the progress bar fills up from 0 to 100. The label never appears. I even threw in a sleep command immediately after the event to be sure I wasn't just missing it, but it's as if the first 2 statements are not being executed. What am I doing wrong here? private void searchButton_Click(object sender, EventArgs e) { toolStripStatusLabel1.Visible = true; toolStripProgressBar1.Value = 20; m_changeRequestedEvents.Fire<String>("SearchTerm", searchTextBox.Text); toolStripProgressBar1.Value = 100; toolStripStatusLabel1.Visible = false; }

  Read the article

• Can I join two tables whereby the joined table is sorted by a certain column?

  - by Ferdy

  I'm not much of a database guru so I need some help on a query I'm working on. In my photo community project I want to richly visualize tags by not only showing the tag name and counter (# of images inside them), I also want to show a thumb of the most popular image inside the tag (most karma). The table setup is as follow: Image table holds basic image metadata, important is the karma field Imagefile table holds multiple entries per image, one for each format Tag table holds tag definitions Tag_map table maps tags to images In my usual trial and error query authoring I have come this far: SELECT * FROM (SELECT tag.name, tag.id, COUNT(tag_map.tag_id) as cnt FROM tag INNER JOIN tag_map ON (tag.id = tag_map.tag_id) INNER JOIN image ON tag_map.image_id = image.id INNER JOIN imagefile on image.id = imagefile.image_id WHERE imagefile.type = 'smallthumb' GROUP BY tag.name ORDER BY cnt DESC) as T1 WHERE cnt > 0 ORDER BY cnt DESC [column clause of inner query snipped for the sake of simplicity] This query gives me somewhat what I need. The outer query makes sure that only tags are returned for which there is at least 1 image. The inner query returns the tag details, such as its name, count (# of images) and the thumb. In addition, I can sort the inner query as I want (by most images, alphabetically, most recent, etc) So far so good. The problem however is that this query does not match the most popular image (most karma) of the tag, it seems to always take the most recent one in the tag. How can I make sure that the most popular image is matched with the tag?

  Read the article

• Object-oriented GUI development in python

  - by ptabatt

  Hey guys, new programmer here. I have an assignment for class and I'm stuck... What I need to do is a create a GUI that gives someone a basic arithmetic problem in one box, asks the person to answer it, evaluates it, and tells you if you're right or wrong... Basically, what I have is this: [code] class Lesson(Frame): def init (self, parent=None): Frame.init(self, parent) self.pack() Lesson.make_widgets(self) def make_widgets(self): Label(self, text="").pack(side=TOP) ent = Entry(self) self.a = randrange(1,10) self.b = randrange(1,10) self.expr = choice(["+","-"]) ent.insert(END, str(self.a) + str(self.expr) + str(self.a)) [/code] I've broken this down into many little steps and basically, what I'm trying to do right now is insert a default random expression into the first entry widget. When I run this code, I just get a blank Label. Why is that? How can I put a something like "7+7" into the box? If you absolutely need background to the problem, it's question #3 on this link. http://reed.cs.depaul.edu/lperkovic/csc242/homeworks/Homework8.html -Thanks for all help in advance.

  Read the article

• Reading/Writing DataTables to and from an OleDb Database LINQ

  - by jsmith

  My current project is to take information from an OleDbDatabase and .CSV files and place it all into a larger OleDbDatabase. I have currently read in all the information I need from both .CSV files, and the OleDbDatabase into DataTables.... Where it is getting hairy is writing all of the information back to another OleDbDatabase. Right now my current method is to do something like this: OleDbTransaction myTransaction = null; try { OleDbConnection conn = new OleDbConnection("PROVIDER=Microsoft.Jet.OLEDB.4.0;" + "Data Source=" + Database); conn.Open(); OleDbCommand command = conn.CreateCommand(); string strSQL; command.Transaction = myTransaction; strSQL = "Insert into TABLE " + "(FirstName, LastName) values ('" + FirstName + "', '" + LastName + "')"; command.CommandType = CommandType.Text; command.CommandText = strSQL; command.ExecuteNonQuery(); conn.close(); catch (Exception) { // IF invalid data is entered, rolls back the database myTransaction.Rollback(); } Of course, this is very basic and I'm using an SQL command to commit my transactions to a connection. My problem is I could do this, but I have about 200 fields that need inserted over several tables. I'm willing to do the leg work if that's the only way to go. But I feel like there is an easier method. Is there anything in LINQ that could help me out with this?

  Read the article

• What changes in Core Data after a save?

  - by Splash6

  I have a Core Data based mac application that is working perfectly well until I save a file. When I save a file it seems like something changes in core data because my original fetch request no longer fetches anything. This is the fetch request that works before saving but returns an empty array after saving. NSEntityDescription *outputCellEntityDescription = [NSEntityDescription entityForName:@"OutputCell" inManagedObjectContext:[[self document] managedObjectContext]]; NSFetchRequest *outputCellRequest = [[[NSFetchRequest alloc] init] autorelease]; [outputCellRequest setEntity:outputCellEntityDescription]; NSPredicate *outputCellPredicate = [NSPredicate predicateWithFormat:@"(cellTitle = %@)", outputCellTitle]; [outputCellRequest setPredicate:outputCellPredicate]; NSError *outputCellError = nil; NSArray *outputCellArray = [[[self document] managedObjectContext] executeFetchRequest:outputCellRequest error:&outputCellError]; I have checked with [[[self document] managedObjectContext] registeredObjects] to see that the object still exists after the save and nothing seems to have changed and the object still exists. It is probably something fairly basic but does anyone know what I might be doing wrong? If not can anyone give me any pointers to what might be different in the Core Data model after a save so I might have some clues why the fetch request stops working after saving?

  Read the article

• Greasemonkey script not executed when unusual content loading is being used

  - by Sam Brightman

  I'm trying to write a Greasemonkey script for Facebook and having some trouble with the funky page/content loading that they do (I don't quite understand this - a lot of the links are actually just changing the GET, but I think they do some kind of server redirect to make the URL look the same to the browser too?). Essentially the only test required is putting a GM_log() on its own in the script. If you click around Facebook, even with facebook.com/* as the pattern, it is often not executed. Is there anything I can do, or is the idea of a "page load" fixed in Greasemonkey, and FB is "tricking" it into not running by using a single URL? If I try to do some basic content manipulation like this: GM.log("starting"); var GM_FB=new Object; GM_FB.birthdays = document.evaluate("//div[@class='UIUpcoming_Item']", document, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null); for (i = GM_FB.birthdays.snapshotLength - 1; i >= 0; i--) { if (GM_FB.birthdayRegex.test(GM_FB.birthdays.snapshotItem(i).innerHTML)) { GM_FB.birthdays.snapshotItem(i).setAttribute('style','font-weight: bold; background: #fffe88'); } } The result is that sometimes only a manual page refresh will make it work. Pulling up the Firebug console and forcing the code to run works fine. Note that this isn't due to late loading of certain parts of the DOM: I have adding some code later to wait for the relevant elements and, crucially, the message never gets logged for certain transitions. For example, when I switch from Messages to News Feed and back.

  Read the article

• Virtual destructor - How does it work?

  - by Prabhu

  Hello All, Few hours back I was fiddling with a Memory Leak issue and it turned out that I really got some basic stuff about virtual destructor wrong!! Let me put explain my class design. class Base { virtual push_elements()<br>{}<br> }; class Derived:public Base { vector<int> x; public: void push_elements(){ for(int i=0;i <5;i++) x.push_back(i); } }; void main() { Base* b = new Derived(); b->push_elements(); delete b; } The bounds checker tool reported a memory leak in the derived class vector. And I figured out that the destructor is not virtual and the derived class destructor is not called.And it surprisingly got fixed when I made the destructor virtual. But my question is "isn't the vector deallocated automatically even if the derived class destructor is not called"? Is that a quirk in BoundsChecker tool or is my understanding of virtual destructor is wrong:)

  Read the article

• OpenAL not playing on Max OS X 10.6

  - by Grimless

  I've been working on getting a basic audio engine running on my Mac using OpenAL. It seems relatively straightforward after working with OpenGL for a while. However, despite the fact that I believe I have everything in place, my sound will not play. Here is the order of things I am doing: //Creating a new device ALCdevice* device = alcOpenDevice(NULL); //Create a new context with the device ALCcontext* context = alcCreateContext(device, NULL); //Make that context current alcMakeContextCurrent(context); //Do lots of loading stuff to bring in an AIFF... voodooAIFF = myAIFFLoader("name"); //Then use that data ALuint buf; alGenBuffers(1, &buf); //Check for errors, but none happen... //Bind buffer data. alBufferData(buf, voodooAIFF.format, voodooAIFF.data, voodooAIFF.sizeInBytes, voodooAIFF.frequency); //Check for errors, none here either... //Create Source ALuint src; alGenSources(1, &src); //Error check again, no errors. //Bind source to buffer alSourcei(src, AL_BUFFER, buf); //Set reference distance alSourcei(sourceID, AL_REFERENCE_DISTANCE, 1); //Set source attributes including gain and pitch to 1 (direction set to 0,0,0) //Check for errors, nothing... //Set up listener attributes. //Check for errors, no errors. //Begin playing. alSourcePlay(src); Observe silence... Any insight, what steps am I missing here?

  Read the article

• MS Word opens documents hosted on WebDav share read-only on Windows Vista and 7 but only if no other

  - by rjmunro

  We have a WebDav server with some Word documents on it. (We are using PHP's HTTP_WebDAV_Server but get the same issue on tests with Apache mod_dav - both use digest authentication, basic auth doesn't work on Vista or later) We have a web page that opens the word documents using javascript like: Doc = new ActiveXObject("Sharepoint.OpenDocuments.3"); Doc.EditDocument(url, 'Word.Document'); which causes word to connect to the webdav server and open the document, bypassing IE and most of windows built in WebDav client. On Windows XP, this works perfectly, and (after prompting you to log in) allows you to edit the word document and save it back to the server. On Windows 7 and Windows Vista, this usually opens the document read only, but not in all cases. After quite a bit of trial and error, we found that it worked (i.e. opened read/write) if Explorer happened to be already connected to a WebDav server. Note that this works with any Webdav server, not neccesarily the one with the document that you are trying to edit. So other than telling our users to change settings on their machine, is there anything we can do in the javascript sharepoint call, or on the WebDav server that will fix this issue. Ps. We have the same problem when launching Word from an HTA file version of our system, with javascript like: wordApp = new ActiveXObject("Word.application"); wordApp = new ActiveXObject("Word.application"); wordApp.Visible = true; doc = wordApp.Documents.Open(url); Pps. Sorry if you think this question should be on Serverfault (or even SuperUser). I couldn't decide, but because we are programming the WebDav server ourself (in PHP) and I have more rep on this site than the others, I decided to post it here :-)

  Read the article

• Does QThread::sleep() require the event loop to be running?

  - by suszterpatt

  I have a simple client-server program written in Qt, where processes communicate using MPI. The basic design I'm trying to implement is the following: The first process (the "server") launches a GUI (derived from QMainWindow), which listens for messages from the clients (using repeat fire QTimers and asynchronous MPI receive calls), updates the GUI depending on what messages it receives, and sends a reply to every message. Every other process (the "clients") runs in an infinite loop, and all they are intended to do is send a message to the server process, receive the reply, go to sleep for a while, then wake up and repeat. Every process instantiates a single object derived from QThread, and calls its start() method. The run() method of these classes all look like this: from foo.cpp: void Foo::run() { while (true) { // Send message to the first process // Wait for a reply // Do uninteresting stuff with the reply sleep(3); // also tried QThread::sleep(3) } } In the client's code, there is no call to exec() anywhere, so no event loop should start. The problem is that the clients never wake up from sleeping (if I surround the sleep() call with two writes to a log file, only the first one is executed, control never reaches the second). Is this because I didn't start the event loop? And if so, what is the simplest way to achieve the desired functionality?

  Read the article

• Write raw struct contents (bytes) to a file in C. Confused about actual size written

  - by d11wtq

  Basic question, but I expected this struct to occupy 13 bytes of space (1 for the char, 12 for the 3 unsigned ints). Instead, sizeof(ESPR_REL_HEADER) gives me 16 bytes. typedef struct { unsigned char version; unsigned int root_node_num; unsigned int node_size; unsigned int node_count; } ESPR_REL_HEADER; What I'm trying to do is initialize this struct with some values and write the data it contains (the raw bytes) to the start of a file, so that when I open this file I later I can reconstruct this struct and gain some meta data about what the rest of the file contains. I'm initializing the struct and writing it to the file like this: int esprime_write_btree_header(FILE * fp, unsigned int node_size) { ESPR_REL_HEADER header = { .version = 1, .root_node_num = 0, .node_size = node_size, .node_count = 1 }; return fwrite(&header, sizeof(ESPR_REL_HEADER), 1, fp); } Where node_size is currently 4 while I experiment. The file contains the following data after I write the struct to it: -bash$ hexdump test.dat 0000000 01 bf f9 8b 00 00 00 00 04 00 00 00 01 00 00 00 0000010 I expect it to actually contain: -bash$ hexdump test.dat 0000000 01 00 00 00 00 04 00 00 00 01 00 00 00 0000010 Excuse the newbiness. I am trying to learn :) How do I efficiently write just the data components of my struct to a file?

  Read the article

• Google app engine: Poor Performance with JDO + Datastore

  - by Bosh

  I have a simple data model that includes USERS: store basic information (key, name, phone # etc) RELATIONS: describe, e.g. a friendship between two users (supplying a relationship_type + two user keys) I'm getting very poor performance, for instance, if I try to print the first names of all of a user's friends. Say the user has 500 friends: I can fetch the list of friend user_ids very easily in a single query. But then, to pull out first names, I have to do 500 back-and-forth trips to the Datastore, each of which seems to take on the order of 30 ms. If this were SQL, I'd just do a JOIN and get the answer out fast. I understand there are rudimentary facilities for performing joins across un-owned relations in a relaxed implementation of JDO (as described at http://gae-java-persistence.blogspot.com) but they sound experimental and non-standard (e.g. my code won't work in any other JDO implementation). Is this really my best bet? Otherwise, how do people extract satisfactory performance from JDO/Datastore in this kind of (very common) situation? -Bosh

  Read the article

• What Do You Need To Write Your Own Blog Engine?

  - by deworde

  I've been messing around with basic websites for a few years, using companies like www.Fasthosts.co.uk to do my web hosting. But I'd like to expand my skills from C++ and Java app programming into Web-based programming, and I think the best way to do that is with a project. I've chosen to go with a blog engine because it's a relative comprehensive yet non-complex project. I'm aware that you can just go to Blogger and bam! One blog. I've done that, so that I can at least have some content, and work out what I want to do with this blog. At the moment, I'm thinking I'll use it to chart my progress creating the blogging engine. But I have some questions. Do you need to be running your own server? Or is it more sensible in the short-term to use a hosting company? What types of language are worth considering? What's important to focus on from a design perspective? What unexpected problems might I encounter?

  Read the article

• Finding Local IP via Socket Creation / getsockname

  - by BSchlinker

  I need to get the IP address of a system within C++. I followed the logic and advice of another comment on here and created a socket and then utilized getsockname to determine the IP address which the socket is bound to. However, this doesn't appear to work (code below). I'm receiving an invalid IP address (58.etc) when I should be receiving a 128.etc Any ideas? string Routes::systemIP(){ // basic setup int sockfd; char str[INET_ADDRSTRLEN]; sockaddr* sa; socklen_t* sl; struct addrinfo hints, *servinfo, *p; int rv; memset(&hints, 0, sizeof hints); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; if ((rv = getaddrinfo("4.2.2.1", "80", &hints, &servinfo)) != 0) { fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv)); return "1"; } // loop through all the results and make a socket for(p = servinfo; p != NULL; p = p->ai_next) { if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) { perror("talker: socket"); continue; } break; } if (p == NULL) { fprintf(stderr, "talker: failed to bind socket\n"); return "2"; } // get information on the local IP from the socket we created getsockname(sockfd, sa, sl); // convert the sockaddr to a sockaddr_in via casting struct sockaddr_in *sa_ipv4 = (struct sockaddr_in *)sa; // get the IP from the sockaddr_in and print it inet_ntop(AF_INET, &(sa_ipv4->sin_addr.s_addr), str, INET_ADDRSTRLEN); printf("%s\n", str); // return the IP return str; }

  Read the article

• How to ensure DB security for a Windows Forms application?

  - by Vilx-

  The basic setup is classic - you're creating a Windows Forms application that connects to a DB and does all kinds of enterprise-y stuff. Naturally, such an application will have many users with different access rights in the DB, and each with their own login name and password. So how do you implement this? One way is to create a DB login for every application user, but that's a pretty serious thing to do, which even requires admin rights on the DB server, etc. If the DB server hosts several applications, the admins are quite likely not to be happy with this. In the web world typically one creates his own "Users" table which contains all the necessary info, and uses one fixed DB login for all interaction. That is all nice for a web app, but a windows forms can't hide this master login information, negating security altogether. (It can try to hide, but all such attempts are easily broken with a bit of effort). So... is there some middle way? Perhaps logging in with a fixed login, and then elevating priviledges from a special stored procedure which checks the username and password?

  Read the article

< Previous Page | 640 641 642 643 644 645 646 647 648 649 650 651  | Next Page >