internals:engine

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internals:engine [2010/04/20 10:38] – created derickinternals:engine [2010/04/20 10:58] – derick
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   * each op_array has an array of literals (constant values)   * each op_array has an array of literals (constant values)
   * opocde operands don't contain zval directly any more but points to thistable instead   * opocde operands don't contain zval directly any more but points to thistable instead
-  * during compilation they are accessible by index e.g. op_array->literals[opline->op1.constant].constant +  * during compilation they are accessible by index e.g: <code>op_array->literals[opline->op1.constant].constant</code> 
-  * the pass_two() changes indexes into pointers so during execution they are accessible by opline->op1.zv+  * the pass_two() changes indexes into pointers so during execution they are accessible by: <code>opline->op1.zv</code> 
 + 
 + 
 +===== FAQ ===== 
 +These are questions, often times with answers, for the PHP Internals. This document is temporary until it's polished and finds a home within the PHP Manual sources. Feel free to add questions with or without answers. 
 + 
 +Note: This is rough, feel free to clean it up. 
 + 
 +==== C++ ==== 
 +Extensions can be written in C++, you have to add PHP_REQUIRE_CXX to the config.m4 file to make the build system C++-aware though. 
 + 
 +To allow static builds of the extension one has to mind this: 
 + 
 +  09:20:43 <johannes_> and ext/extname/php_extname.h has to be a valid C header, not C++, as it's included in internal_functions.c ... 
 +  09:22:06 <dsp_> hmm, that's the point.. 
 +  09:23:01 <johannes_> you can have your own additional header for C++ suff, but that one has to be C compatible 
 + 
 + 
 +==== Memory Management ==== 
 + 
 +  [12:00pm] scoates: ok.. last question for now, I think: should I explicitly destroy on RSHUTDOWN, or let the non-persistent flag take care of that? 
 +  [12:00pm] johannes_: always cleanup yourself 
 + 
 +Note here: while MM shutdown will take care of all allocated memory, it won't run any dtors etc., that's why it is important to clean up the resources properly - otherwise external dependencies can be messed up. And of course you'd get leaks reported in the debug mode.  
 + 
 +==== Causes for crashes ==== 
 + 
 +=== Throwing Exceptions === 
 + 
 +If throwing exceptions results in a segmentation fault on 64bit systems only, then be sure that you have: 
 +  #include "zend_exceptions.h"  
 + 
 +(Remark: This header is always needed. The segfault might be caused by the fact, that C defaults the return value and parameters of undefined parameters to int. In cases where pointers and/or long data types are needed this might be wrong so a wrong function call is being made. A good compiler should give a warning. --johannes) 
 + 
 +==== Hashes ==== 
 +  [11:58am] scoates: what's the difference between zend_hash_[add] and zend_hash_quick_[add] ? 
 +  [11:58am] scoates: removal of gofaster loops? (-: 
 +  [11:58am] Derick: with the 2nd one you can provide an already calculated hash-list index 
 + 
 +  [11:59am] scoates: and the hashtable will automatically grow on _add, right? the length passed to init is just a hint? 
 +  [11:59am] johannes_: right
  
internals/engine.txt · Last modified: 2017/09/22 13:28 by 127.0.0.1

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