Questions tagged [php-internals]
How the PHP programming language works underneath, and questions about the underlying C code.
php-internals
268
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Adding new reference to any item in array affects behaviour of the array
I've seen many questions about this (one of them here)
$a = array('a', 'b', 'c', 'd');
foreach ($a as &$v) { }
foreach ($a as $v) { }
print_r($a);
and I get the answers, you shouldn't be ...
- 16
0
votes
1
answer
58
views
in php programming where is the array data and the address being stored?
i am new to php . i want to know the place where the array data and the address of array are being stored ?
are they storing in heap and stack , respectivelylike C# ?
I read many articles but I could ...
1
vote
0
answers
35
views
Are PHP zvals mutable?
I've been reading about memory management in PHP and learned that variables in PHP copy the reference to zvals as long as you don't do a write operation (copy on write paradigm).
https://www....
- 338
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0
answers
23
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Is there an opcode in PHP VM that lets you stack allocate?
Title. Since you can enable escape analysis, there should also be an opcode that uses stack allocation instead of heap, right? Or how would that work?
- 3,914
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267
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How to create a php extension function with a return type-hint plus annotation
I'm trying to fix some php 8.1 deprecation notices in a PHP extension, which I believe involves either adding return type-hints (where possible, whilst maintaining some backwards-compatibility to php7....
- 612
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1
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253
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How do I add a new opcode to PHP?
Searching for it I found this blog post: https://www.npopov.com/2017/04/14/PHP-7-Virtual-machine.html
Does it cover "everything" needed to add a new opcode, or all the places I'd need to ...
- 3,914
4
votes
0
answers
268
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PHP5 zval container vs PHP7 zval container. How references & variables are stored now?
I am following a tutorial & reading through some articles on how variables are stored in PHP using zval (zend value) container. Most of those articles seem to be following & getting ...
- 113
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174
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How to call a PHP function from zend_compile.c?
I can't figure out how to call an existing PHP function, everytime I end up either with a segmentation fault or a Fatal error.
Disclaimer: I'm not experienced at all in low level programming, just ...
- 754
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1
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191
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Why the macro "ZVAL_COPY_VALUE(z,v)" seems to work unexpectedly in PHP Internal?
My question is about HashTable:
The PHP VERSION debugged is PHP-7.0.12, I couldn't find out where the zval's str member is updated within the macro "ZVAL_COPY_VALUE(z, v)" when I add one new ...
- 33
4
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1
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266
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Where is PHP echo implemented in the source?
You can lookup built-in functions by searching for e.g. PHPAPI(stream_copy_to_stream) and find the implementation in ext/standard/streamsfuncs.c.
How to do that for a language construct like echo?
I ...
- 1,877
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424
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PHP memory limit -1 unlinimited
In PHP 5.4 How much memory is allocated to a script, when we set memory_limit to -1 ?
Memory exhausted error will not come until all memory is exhausted .
But will this affect my other processes too? ...
9
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1
answer
3k
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What was PHP's "o" serialization format for?
The list of backwards-incompatible changes for PHP 7.4 contain the following note:
Serialization
The o serialization format has been removed. As it is never produced by PHP, this may only break ...
- 1,283
4
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0
answers
320
views
What userland strings get automatically interned by PHP?
I was trying to get a better understanding of PHP's internal mechanisms of string interning - more specifically:
What are the rules PHP uses to determine whether (or not) the string created in ...
- 6,475
1
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1
answer
508
views
What are the limits on session names in PHP?
The PHP docs on session_name() say:
It should contain only alphanumeric characters; it should be short and descriptive (i.e. for users with enabled cookie warnings). ... The session name can't ...
- 37k
2
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341
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how to allocate & deallocate memory in php?
I'm trying to allocate memory dynamically in my code and release them ,I tried to use zend_mm but I couldn't add it to php 7,I'm using php 7.4 and xampp server , if it is impossible please tell my the ...
- 21
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1
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507
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How can I overwrite an internal Zend function with a PHP extension?
Hope this isn't too silly a question to ask. I'm fairly new to C and PHP internals but looking to learn more about them.
I've recently began looking into development of PHP extensions. I'm trying to ...
- 11
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77
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Passing HashTable data from php.ini to an extension method: corrupted values
I am trying to make a PHP (7.4) extension use in an extension method a setting from php.ini (like myext.map=key1=val1,key2=val2;) parsed as an associative array. I want the parsing to happen in ...
- 4,284
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92
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Are `zval *retval` argument and the `zval *` return value of the `zend_call_method` the same?
Is the zval * value returned by the zend api method zend_call_method same as the zval *retval argument passed into it?
I can see that zend_call_method is declared in zend_interfaces.h. I tried ...
- 20.3k
4
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700
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Why does php allow invalid return type declerations it knows it can't allow?
As far as I can tell php has the ability to prevent a return type from being declared where it knows it's problematic.
class Foo {
public function __clone(): Baz {
return new Baz;
}
}
...
- 83
4
votes
1
answer
930
views
Where is the source code for strlen() function in PHP?
I was looking through php-src/Zend/zend_API.c and couldn't find the source code for the strlen() function in PHP anywhere. Grepping through the code base didn't really help as it's littered with libc ...
- 83
2
votes
3
answers
2k
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How come usort (php) works even when not returning integers?
Yesterday at work I stumbled upon a piece of code that was roughly like this:
uasort($array, function($a, $b) {
return isset($a['sort_code']) && isset($b['sort_code']) && $a['...
- 21
8
votes
3
answers
433
views
Duplicate array keys (Notice: member variable "a" returned from __sleep() multiple times)
The title may seem a bit silly but I'm totally serious with this. Today at work I came across a weird PHP behaviour which I could not explain. Luckily this behaviour is fixed in PHP 7.4, so it seems ...
- 2,749
2
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1
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226
views
Does mysqli_close() do anything other than just destroying the object?
I know that using mysqli_close() is not needed, because PHP will destruct the object when the script is finished.
What I would like to know is why do we have such a function in the language in the ...
- 32.6k
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1
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425
views
Segfault Error when using zend_call_function()
i am trying to warp a C library around a PHP class using PHP's Zend Engine. The constructor function of the class is supposed to take a string and a function pointer. I was able to fetch strings ...
- 1,018
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1
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277
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What is causing this strange memory corruption in my test PHP extension?
I recently needed a list of compiled-in signal names so I could print nice messages like "Interrupted by SIGINT (2)".
get_defined_constants() is unusable for this as it jumbles SIGINT, SIGTRAP etc in ...
- 1,961
2
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1
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540
views
pdo_module.obj : error LNK2019: unresolved external symbol "int __cdecl php_pdo_register_driver(struct pdo_driver_t *)"
LINK: unresolved external symbol :php_pdo_register_driver
I'm writing a PHP PDO ext demo with PHP7.2.21, when I tried to register my ext on PDO, I got an error.
PHP_MINIT_FUNCTION(pdo_my_mysql) {
#...
- 81
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1
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162
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Is there a way in php to count the nested stucture level?
I'm experimenting with a way to more easily debug Cronjob Scripts with PHP.
without having xdebug etc. accessible on the server.
For this, I'd like to get the number of nested structures the code ...
- 137
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0
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52
views
PHP API Reflection
I want to find where such messages are generated at a low level.
Uncaught TypeError: Argument 1 passed to A::__construct() must be an instance of B
I downloaded the source PHP 7. And tried to find ...
- 121
11
votes
2
answers
1k
views
Why is in_array strict mode on integers slower than non-strict mode?
I always thought that in_array strict mode will be faster or at least the same speed as non-strict mode. But after some benchmarks I noticed there is a huge difference in execution time between them ...
- 379
4
votes
1
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371
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Why increasing refcount of zval not working?
I'm dumping a zval container running on PHP version 7.3.5 (opcache is activated and PHP is thread safe enabled) following this given code :
<?php
$a = "new string";
$b = $a;
xdebug_debug_zval( '...
- 131