Questions tagged [php-internals]
How the PHP programming language works underneath, and questions about the underlying C code.
php-internals
268
questions
2282
votes
7
answers
459k
views
How does PHP 'foreach' actually work?
Let me prefix this by saying that I know what foreach is, does and how to use it. This question concerns how it works under the bonnet, and I don't want any answers along the lines of "this is how you ...
- 88.4k
133
votes
41
answers
187k
views
What does "zend_mm_heap corrupted" mean
All of the sudden I've been having problems with my application that I've never had before. I decided to check the Apache's error log, and I found an error message saying "zend_mm_heap corrupted". ...
- 1,694
52
votes
2
answers
3k
views
Parentheses altering semantics of function call result
It was noted in another question that wrapping the result of a PHP function call in parentheses can somehow convert the result into a fully-fledged expression, such that the following works:
<?php
...
46
votes
2
answers
22k
views
What's the difference between "extension" and "zend_extension" in php.ini?
When I installed Xdebug through pecl, it added the following line to my php.ini file.
extension="xdebug.so"
and everything I used worked. Until today.
Today I was having trouble setting up Xdebug ...
- 165k
44
votes
1
answer
3k
views
What is the difference between while(true) and for(;;) in PHP?
Is there any difference in PHP between while(true) and for(;;) besides syntax and readability?
- 1,780
43
votes
6
answers
6k
views
Why don't PHP attributes allow functions?
I'm pretty new to PHP, but I've been programming in similar languages for years. I was flummoxed by the following:
class Foo {
public $path = array(
realpath(".")
);
}
It produced a ...
- 161k
31
votes
4
answers
7k
views
Where can I learn about PHP internals? [closed]
What are good resources to start learning the internals of PHP and the Zend Engine?
- 22.8k
29
votes
1
answer
5k
views
Where's the php-src/PHP-Internals Main Entry Point
What function or bit of code serves as the main entry point for executing/interpreting a PHP program in the source of PHP itself? Based on things I've googled or read in books, I know that PHP is ...
- 165k
29
votes
0
answers
1k
views
Pre-compiling PHP files [closed]
As a learning exercise, I'm trying to save the compiled state of a PHP file in order to execute it at a later time without having to go through zend_compile_file again.
The first thing I did was ...
- 1,307
28
votes
1
answer
992
views
Why can't you inherit from a not-yet-defined class which inherits from a not-yet-defined class?
I research about class compilation, it's sequence, and logic.
If I declare a class before a simple parent:
class First extends Second{}
class Second{}
This will work OK. See live example across ...
- 5,210
27
votes
5
answers
7k
views
Detecting whether a PHP variable is a reference / referenced
Is there a way in PHP to determine whether a given variable is a reference to another variable and / or referenced by another variable? I appreciate that it might not be possible to separate ...
- 17.3k
26
votes
5
answers
10k
views
How are associative arrays implemented in PHP?
Can someone explain how PHP implements associative arrays? What underlying data structure does PHP use? Does PHP hash the key and store it in some kind of hash map? I am curious because I was ...
Y Pgjn
25
votes
3
answers
5k
views
In which order are objects destructed in PHP?
What is the exact order of object deconstruction?
From testing, I have an idea: FIFO for the current scope.
class test1
{
public function __destruct()
{
echo "test1\n";
}
...
- 3,154
25
votes
1
answer
1k
views
Get PHP Opcodes Dynamically at Runtime
I want to build a PHP extension that can dynamically inspect every opcode generated from a PHP file and do some checking on that.
I came across several websites and found out a couple of functions ...
- 287
22
votes
4
answers
4k
views
How does PHP memory actually work
I've always heard and searched for new php 'good writing practice', for example: It's better (for performance) to check if array key exists than search in array, but also it seems better for memory ...
- 7,639