Search Results

Search found 16311 results on 653 pages for 'environment variables'.

Page 357/653 | < Previous Page | 353 354 355 356 357 358 359 360 361 362 363 364  | Next Page >

• Corrupted image if variable is not static

  - by Jaka Jancar

  I'm doing the following: static GLfloat vertices[3][3] = { {0.0, 1.0, 0.0}, {1.0, 0.0, 0.0}, {-1.0, 0.0, 0.0} }; glColor4ub(255, 0, 0, 255); glEnableClientState(GL_VERTEX_ARRAY); glVertexPointer(3, GL_FLOAT, 0, vertices); glDrawArrays(GL_TRIANGLES, 0, 9); glDisableClientState(GL_VERTEX_ARRAY); This works ok: However, if I remove static from vertices and therefore re-create the data on the stack on each rendering, I get the following: This happens both on the simulator and on the device. Should I be keeping the variables around after I call glDrawArrays?

  Read the article

• PHP Sessions - Locking and Sharing questions

  - by Nuno Peralta

  Hi, I would like to know if it is possible to read $_SESSION attributes without locking it. Currently, session_start() locks SESSION, that means other PHP processes will wait until it is unlocked. But, some processes just want to get some $_SESSION variables, not to write on them. Is that possible to implement some function like session_get(string $id) which doesn't lock SESSION? Also, it is possible to share SESSIONs between browsers, once the user is logged in the same account, for example, using session_id('shared_vars_of_'.$userid). But, is that secure? Is this discouraged? Thanks, Nuno

  Read the article

• javascript table - update on data request

  - by flyingcrab

  Hi, I am trying to update a table based on a json request. The first update / draw works fine - but any subsequent changes to the variables (the start and end date) do not show up - even though the json pulled from the server seems to be correct (according to firebug). AFAIK the code below should re-initialize everything - no sure what is going on (I'm using the Google vizulization api)? function handleQueryResponse(response) { if (response.isError()) { //alert('Error in query: ' + response.getMessage() + ' ' + response.getDetailedMessage()); return; } visualization = new google.visualization.Table(document.getElementById('visualization')); visualization.draw(response.getDataTable(), null); } One more thing: I'm working on a page that displays textbased tables and currently trying to decide between the google table (viz api) and a jQuery alternative I came across jqGrid any good ones I am missing?

  Read the article

• How to signal a buffer full state between posix threads

  - by mikip

  Hi I have two threads, the main thread 'A' is responsible for message handling between a number of processes. When thread A gets a buffer full message, it should inform thread B and pass a pointer to the buffer which thread B will then process. When thread B has finished it should inform thread A that it has finished. How do I go about implementing this using posix threads using C on linux. I have looked at conditional variables, is this the way to go? . I'm not experienced in multi threaded programming and would like some advice on the best avenue to take. Thanks

  Read the article

• "Anagram solver" based on statistics rather than a dictionary/table?

  - by James M.

  My problem is conceptually similar to solving anagrams, except I can't just use a dictionary lookup. I am trying to find plausible words rather than real words. I have created an N-gram model (for now, N=2) based on the letters in a bunch of text. Now, given a random sequence of letters, I would like to permute them into the most likely sequence according to the transition probabilities. I thought I would need the Viterbi algorithm when I started this, but as I look deeper, the Viterbi algorithm optimizes a sequence of hidden random variables based on the observed output. I am trying to optimize the output sequence. Is there a well-known algorithm for this that I can read about? Or am I on the right track with Viterbi and I'm just not seeing how to apply it?

  Read the article

• Are returned locals automatically xvalues

  - by mark

  Following on from a comment I made on this: passing std::vector to constructor and move semantics Is the std::move necessary in the following code, to ensure that the returned value is a xvalue? std::vector<string> buildVector() { std::vector<string> local; // .... build a vector return std::move(local); } It is my understanding that this is required. I have often seen this used when returning a std::unique_ptr from a function, however GManNickG made the following comment: It is my understanding that in a return statement all local variables are automatically xvalues (expiring values) and will be moved, but I'm unsure if that only applies to the returned object itself. So OP should go ahead and put that in there until I'm more confident it shouldn't have to be. :) Can anyone clarify if the std::move is necessary? Is the behaviour compiler dependent?

  Read the article

• Integers in JavaScript

  - by muntoo

  I'm a beginner to Javascript so forgive me if I sound dumb because I learned some Javascript from W3Fools (which are really difficult tutorials - they don't explain anything I want to know, but everything I probably can guess from my experience with C++). I may be switching over to MDN, but if you can recommend any other tutorials, that be great. Anyways, so here's my question: I just read a few lines of this, and apparently: Numbers in JavaScript are "double-precision 64-bit format IEEE 754 values", according to the spec. This has some interesting consequences. There's no such thing as an integer in JavaScript, so you have to be a little careful with your arithmetic if you're used to math in C or Java. I've already seen that there are few of the data types (for variables) I'm used to from C++. But I didn't expect all numbers to automatically be floats. Isn't there any way to use integers, not float? Will a future version of JavaScript support ints?

  Read the article

• Posting null values via AJAX

  - by nickf

  Using the jQuery $.post function, if you send a null value, it arrives at the server side as "null". Example: Javascript: $.post('test.php', { foo : null }); PHP: var_dump($_POST['foo']); // string(4) "null" I understand why this is so, but was wondering the best way to work around the limitation? Should you: Loop through all the variables in JS before you send them and replace with an empty string? Interpret "null" as null on the server side? Don't send the variable at all? Something else?

  Read the article

• C++ word to bytes

  - by Vit

  Hi, I tried to read CPUID using assembler in C++. I know there is function for it in , but I want the asm way. So, after CPUID is executed, it should fill eax,ebx,ecx registers with ASCII coded string. But my problem is, since I can in asm adress only full, or half eax register, how to break that 32 bits into 4 bytes. I used this: #include <iostream> #include <stdlib.h> int main() { _asm { cpuid /*There I need to mov values from eax,ebx and ecx to some propriate variables*/ } system("PAUSE"); return(0); }

  Read the article

• Does a C++ destructor always or only sometimes call data member destructors?

  - by Magnus

  I'm trying to validate my understanding of C++ destructors. I've read many times that C++ supplies a default destructor if I don't write one myself. But does this mean that if I DO write a destructor that the compiler WON'T still provide the default cleanup of stack-allocated class fields? My hunch is that the only sane behavior would be that all class fields are destroyed no matter what, whether I provide my own destructor or not. In which case the statement I've read so many times is actually a little misleading and could be better stated as: "Whether or not you write your own destructor, the C++ compiler always writes a default destructor-like sequence to deallocate the member variables of your class. You may then specify additional deallocations or other tasks as needed by defining your own destructor" Is this correct?

  Read the article

• For what purpose does java have a float primitive type?

  - by Roman

  I heard plenty times different claims about float type in java. The most popular issues typicaly regard to converting float value to double and vice versa. I read (rather long time ago and not sure that it's actual now with new JVM) that float gives much worse performance then double. And it's also not recommended to use float in scientific applications which should have certain accuracy. I also remember that when I worked with AWT and Swing I had some problems with using float or double (like using Point2D.Float or Point2D.Double). So, I see only 2 advantages of float over double: it needs only 4 bytes while double needs 8 bytes JMM garantees that assignment operation is atomic with float variables while it's not atomic with double's. Are there any other cases where float is better then double? Do you use float's in your applications? It seems to me that the only valuable reason java has float is backward compatibility.

  Read the article

• Inline function and calling cost in C

  - by Eonil

  I'm making a vector/matrix library. (GCC, ARM NEON, iPhone) typedef struct{ float v[4]; } Vector; typedef struct{ Vector v[4]; } Matrix; I passed struct data as pointer to avoid performance degrade from data copying when calling function. So I thought designed function like this: void makeTranslation(const Vector* factor, Matrix* restrict result); But, if function is inline, is there any reason to pass values as pointer for performance? Do those variables copied too? How about register and caches? inline Matrix makeTranslation(Vector factor) __attribute__ ((always_inline)); How do you think about calling costs of each cases?

  Read the article

• PHP: passing GET between multiple pages

  - by aterimperator

  I'm building a set of pages where I have a number of GET variables and it is often valuable to keep passing it along to the next page. This leads to ugly code where I have to have "if this $_GET variable is set, dynamically add it to this hyperlink". This is, in many senses, not a problem; but I had the thought "there must be a better way to do this", I mean after all basically all I want is to take the '?' and everything after it and append it to the links on that page, it would seem this should be rather simple (or at least possible to do in a for loop). I tried google searching but couldn't find anything, so I figured I'd see if any of you happen to know. Why not use SESSION? Because these pages need to be capable of being bookmarked. Thank you.

  Read the article

• JS function returning another function

  - by Michael

  I want to understand about variables, that has been used in returning function. This is example code Prototype = {} Prototype.F = { bind: function() { var args = arguments, __method = args.shift(), object = args.shift(); return function() { return __method.apply(object, args.concat(arguments)); } } } function ObjectA() { ... this.addListener = Prototype.F.bind(this.eventSource.addListener, this.eventSource); ... } var a = ObjectA(); a.addListener(this); // assuming 'this' here will point to some window object As I understand the returning function in F() is not evaluated until it's called in the last line. It's ok to accept. So addListener will hold a function body containing 'apply'. But what I don't understand, when addListener is called, what kind of parameters it is going to have? particularly _method and args will always be uninitialized?

  Read the article

• Create a triangle out of stars using only recursion

  - by Ramblingwood

  I need to to write a method that is called like printTriangle(5);. We need to create an iterative method and a recursive method (without ANY iteration). The output needs to look like this: * ** *** **** ***** This code works with the iterative but I can't adapt it to be recursive. public void printTriangle (int count) { int line = 1; while(line <= count) { for(int x = 1; x <= line; x++) { System.out.print("*"); } System.out.print("\n"); line++; } } I should not that you cannot use any class level variables or any external methods. Thanks.

  Read the article

• Why doesn't CSS support constants?

  - by Adiel Mittmann

  CSS has never supported constants or variables directly. Whenever I'm writing code like this: span.class1 { color: #377fb6; } div.class2 { border: solid 1px #377fb6; /* Repeated color */ } I wonder why such a seemingly simple feature has never made it into the standard. What could be hard about implementing a scheme whereby we could avoid repetition, something like this: $theme_color1: #377fb6; span.class1 { color: $theme_color1; } div.class2 { border: solid 1px $theme_color1; } I know there are workarounds, like using a class for each color or generating CSS code from templates, but my question is: given that CSS is so rich and complex, why weren't CSS constants ever introduced?

  Read the article

• Question about the lifecycle of a simple Android application

  - by jul

  Hi, I've got a simple application with 3 activities: -the first contains a search box which calls a web service and show the results (restaurants) below in a listview -when a restaurant is clicked another activity is started showing the description of the restaurant and a button "show map" -when the button "show map" is clicked, guess what, the map is shown in a third activity. All the data is loaded in the first activity by a web service (restaurant descriptions and coordinates), and data required by each activity is passed in a bundle using "intent.putExtra". Now everything seems to run smoothly when clicking on the back button (eg. clicking on the back button from the map resumes the "restaurant description" activity with all data set properly), while I haven't done anything about the lifecycle yet. Why? Are all variables saved automatically? Should I use onSaveInstanceState() and onRestoreInstanceState() anyway? Thanks Jul

  Read the article

• R: how can I concatenate a list?

  - by John

  I'm trying to produce a single variable which is a concatenation of two chars e.g to go from "p30s4" "p28s4" to "p30s4 p28s4". I've tried cat and paste as shown below. Both return empty variables. What am I doing wrong? > blah = c("p30s4","p28s4") > blah [1] "p30s4" "p28s4" > foo = cat(blah) p30s4 p28s4 > foo NULL > foo = paste(cat(blah)) p30s4 p28s4 > foo character(0)

  Read the article

• Body class for controller in Rails app.

  - by Vincent

  Currently I have this in my layout: <body class="<%= controller.controller_name %>"> I want to add an additional class that will be the same for all actions in any controller where it's set, something like: class SomeController < ApplicationController body_class 'page' ... end class AnotherController < ApplicationController body_class 'page' ... end Which will result in: <body class="some page"> <body class="another page"> What would be the easiest way to achieve this? Can I use controller class variables for this?

  Read the article

• local match kickoff time

  - by Usagi Dreamy

  I'm working on a sports website and need to convert the server's match start time to local match start time. After much googling, I figured the fastest and most accurate way is to get the GMT offset value in JavaScript. The trouble is, I can't pass the GMT offset value to PHP. I've tried using both the PHP session and cookie variables, but both are always empty. The website doesn't require a user account, so there isn't any stored GMT value in the database. I'm trying to auto-detect each user's local timezone every time he/she visits the website, and then calculate the local match start time based on the timezone offset. Can someone please advise me? Thanks.

  Read the article

• Passing objects by reference or not in C#

  - by Piku

  Suppose I have a class like this: public class ThingManager { List<SomeClass> ItemList; public void AddToList (SomeClass Item) { ItemList.Add(Item); } public void ProcessListItems() { // go through list one item at a time, get item from list, // modify item according to class' purpose } } Assume "SomeClass" is a fairly large class containing methods and members that are quite complex (List<s and arrays, for example) and that there may be a large quantity of them, so not copying vast amounts of data around the program is important. Should the "AddToList" method have "ref" in it or not? And why? It's like trying to learn pointers in C all over again ;-) (which is probably why I am getting confused, I'm trying to relate these to pointers. In C it'd be "SomeClass *Item" and a list of "SomeClass *" variables)

  Read the article

• How to get the first non-null value in Java?

  - by froadie

  Is there a Java equivalent of SQL's COALESCE function? That is, is there any way to return the first non-null value of several variables? e.g. Double a = null; Double b = 4.4; Double c = null; I want to somehow have a statement that will return the first non-null value of a, b, and c - in this case, it would return b, or 4.4. (Something like the sql method - return COALESCE(a,b,c)). I know that I can do it explicitly with something like: return a != null ? a : (b != null ? b : c) But I wondered if there was any built-in, accepted function to accomplish this.

  Read the article

• How does an interpreter switch scope?

  - by Dox

  I'm asking this because I'm relatively new to interpreter development and I wanted to know some basic concepts before reinventing the wheel. I thought of the values of all variables stored in an array which makes the current scope, upon entering a function the array is swapped and the original array put on some sort of stack. When leaving the function the top element of the "scope stack" is popped of and used again. Is this basically right? Isn't swapping arrays (which means moving around a lot of data) not very slow and therefore not used by modern interpreters?

  Read the article

• Issue with plotting daily data using ggplot

  - by user1723765

  I tried to plot daily data from 9 variables in ggplot, but the graph I get cannot handle the date variable properly. The x axis is unreadable and its impossible to read the plot. I'm guessing there's an issue with the handling of dates. Here's the data: https://dl.dropbox.com/u/22681355/su.csv Here's the code I've been using: su=read.csv(file="su.csv", head=TRUE) meltdf=melt(su) ggplot(meltdf, aes(x=Date, y=value, colour=variable, group=variable))+geom_line() and here's the output: https://dl.dropbox.com/u/22681355/output.jpg here's the same plot done in excel, why does it look completely different?

  Read the article

• turning text into image - PHP/GD - save image

  - by Phil Jackson

  Hi, I'm using this script to simply create an image from text. What I would like to know is how to save the image instead of printing straight to browser; // an email address in a string $string = $post[$key]; // some variables to set $font = 4; $width = ImageFontWidth($font) * strlen($string); $height = ImageFontHeight($font); // lets begin by creating an image $im = @imagecreatetruecolor ($width,$height); //white background $background_color = imagecolorallocate ($im, 255, 255, 255); //black text $text_color = imagecolorallocate ($im, 0, 0, 0); // put it all together $image = imagestring ($im, $font, 0, 0, $string, $text_color); I know its probably just one line of code at the end but im not sure which GD function to use. Any help would be much appreciated, Regards, Phil.

  Read the article

< Previous Page | 353 354 355 356 357 358 359 360 361 362 363 364  | Next Page >