What happens in memory when a C++ class is instantiated -

-

i'm interested in nuts , boltw of c++ , wondered changes when object instantiated. i'm particularly interested if functions added memory, if there runtime or if never stored in memory @ all.

if direct me site on of core bolts of c , c++, i'd love too.

thanks, jo

a common case is:

  1. memory allocated calling operator new. function in memory, it's needed lot.
  2. the constructor of class called. code in memory. if not, call function page-faults. os notes, , loads appropriate page executable ram. tells os retry. ( 2a. ctor arranges virtual functions callable - writing vtable pointer )
  3. chances page constructor contains other members of class. can called too. if on page, calling them may cause page fault , load. if compiler put vtable on different page, use of vtable may cause page fault.

the advantage of such load-on-demand mechanism os can avoid loading code class cprinter if user never intends print document.


Comments

Post a Comment

Popular posts from this blog

javascript - Enclosure Memory Copies -

-
function myclass() { //lots , lots of vars , code here. this.bar = function() { //do numerous enclosed myclass vars } this.foo = function() { alert('hello'); //don't enclosed variables. } } each instance of myclass gets own copy of bar , foo, why prototyped methods use less memory. however, know more memory use of inner methods. it seems obvious me (1) below must true. agree? not distinct myclass instances have own distinct copies of bar, must have own distinct copies of myclass enclosure. (or else how bar method keep myclass variables straight on per instance basis?) now (2) question i'm after. since inner foo method doesn't use in myclass enclosure natural qustion is: javascript smart enough not keep myclass enclosure in memory use of foo? this depend entirely on implementation not language. naive implementations keep far more around others. answer true e.g. v8 (chrome's js engine) may not true spider...
Read more

php - Replacing tags in braces, even nested tags, with regex -

-
example preg_replace('/\{[a-za-z.,\(\)0-9]+\}/', 'replaced', 'lorem ipsum dolor sit {tag1({tag2()})}, consectetur adipiscing elit.'); the result: lorem ipsum dolor sit {tag1(replaced)}, consectetur adipiscing elit. question as can see "tag2" has been replaced, want replace "tag1" know how can this? (in cases might this: {tag1({tag2({tag3()})})}) , on.) btw using preg_replace_callback, easier show preg_replace here site can test code: http://www.spaweditor.com/scripts/regex/index.php you need add curly braces character set. here's pattern used: /\{[a-za-z.,\(\)\{\}0-9]+\}/ and here result: "lorem ipsum dolor sit replaced, consectetur adipiscing elit."
Read more