|
|
 |
第 47章Creating Extensions
We'll start with the creation of a very simple extension at first, which
basically does nothing more than implement a function that returns the
integer it receives as parameter. 例47-1 shows the source.
例 47-1. A simple extension. /* include standard header */
#include "php.h"
/* declaration of functions to be exported */
ZEND_FUNCTION(first_module);
/* compiled function list so Zend knows what's in this module */
zend_function_entry firstmod_functions[] =
{
ZEND_FE(first_module, NULL)
{NULL, NULL, NULL}
};
/* compiled module information */
zend_module_entry firstmod_module_entry =
{
STANDARD_MODULE_HEADER,
"First Module",
firstmod_functions,
NULL,
NULL,
NULL,
NULL,
NULL,
NO_VERSION_YET,
STANDARD_MODULE_PROPERTIES
};
/* implement standard "stub" routine to introduce ourselves to Zend */
#if COMPILE_DL_FIRST_MODULE
ZEND_GET_MODULE(firstmod)
#endif
/* implement function that is meant to be made available to PHP */
ZEND_FUNCTION(first_module)
{
long parameter;
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "l", ¶meter) == FAILURE) {
return;
}
RETURN_LONG(parameter);
} |
|
This code contains a complete PHP module. We'll explain the source
code in detail shortly, but first we'd like to discuss the build
process. (This will allow the impatient to experiment before we
dive into API discussions.)
注意:
The example source makes use of some features introduced with the Zend version
used in PHP 4.1.0 and above, it won't compile with older PHP 4.0.x versions.
There are basically two ways to compile modules:
Use the provided "make" mechanism in the
ext directory, which also allows building
of dynamic loadable modules.
Compile the sources manually.
The first method should definitely be favored,
since, as of PHP 4.0, this has been standardized into a
sophisticated build process. The fact that it is so sophisticated
is also its drawback, unfortunately - it's hard to understand at
first. We'll provide a more detailed introduction to this later in
the chapter, but first let's work with the default files.
The second method is good for those who (for some reason) don't
have the full PHP source tree available, don't have access to all
files, or just like to juggle with their keyboard. These cases
should be extremely rare, but for the sake of completeness we'll
also describe this method.
After you run buildconf, configure
--help shows the following additional modules:
--enable-array_experiments BOOK: Enables array experiments
--enable-call_userland BOOK: Enables userland module
--enable-cross_conversion BOOK: Enables cross-conversion module
--enable-first_module BOOK: Enables first module
--enable-infoprint BOOK: Enables infoprint module
--enable-reference_test BOOK: Enables reference test module
--enable-resource_test BOOK: Enables resource test module
--enable-variable_creation BOOK: Enables variable-creation module |
The module shown earlier in 例47-1
can be enabled with
--enable-first_module or
--enable-first_module=yes.
Note: All include paths in the example are
relative to the directory ext. If you're
compiling from another directory, change the pathnames
accordingly. Required items are the PHP directory, the
Zend directory, and (if necessary), the
directory in which your module resides.
The link command is also a plain vanilla command instructing linkage as a dynamic module.
You can include optimization options in the compilation
command, although these have been omitted in this example (but some are included in the makefile
template described in an earlier section).
Note: Compiling and linking manually as a
static module into the PHP binary involves very long instructions
and thus is not discussed here. (It's not very efficient to type
all those commands.)
 add a note
User Contributed Notes
Creating Extensions
markjolesen at muchomail dot com
08-Dec-2004 10:17
To correctly compile the example source to use dynamic linking, change the compile flag -DCOMPILE_DL to -DCOMPILE_DL_FIRST_MODULE. Otherwise, you'll get an invalid library when calling dl().
ywarnier at beeznest dot org
25-Oct-2004 11:19
Quick note to save time to beginners
To make the example above work, I had to add -I../TSRM because the file tsrm_virtual_cwd.h couldn't be found otherwise (it's located in the TSRM directory which is not included above)
In my case (pure Debian Woody install), php libraries were located in /usr/include/php4 (and php.h was in the 'main' subdirectory) so I had to use this path instead of /usr/local/include
someone at apple
02-May-2004 05:55
When following the directions for compiling via make, it may be necessary to delete the configure script before running buildconf. Otherwise you may get a complaint about buggy cache code and the configure script won't actually be updated.
Carl
02-Jul-2003 12:38
I had some problems with "undefined function".
Fatal error: Call to undefined function: csgetmap()
while trying to access by ZEND FUNCTION csGetMap
I the problem fixed it by making ALL FUNCTIONS LOWER CASE.
eg:
[SNIP------------------------------------------]
/* include standard header */
#include "php.h"
/* declaration of functions to be exported */
ZEND_FUNCTION(first_module);
ZEND_FUNCTION(cs_get_map);
ZEND_FUNCTION(cs_get_stats);
/* compiled function list so Zend knows what's in this module */
zend_function_entry coreSO_functions[] =
{
ZEND_FE(first_module, NULL)
ZEND_FE(cs_get_map, NULL)
ZEND_FE(cs_get_stats, NULL)
{NULL, NULL, NULL}
};
/* compiled module information */
zend_module_entry coreSO_module_entry =
{
STANDARD_MODULE_HEADER,
"First Module",
coreSO_functions,
NULL,
NULL,
NULL,
NULL,
NULL,
NO_VERSION_YET,
STANDARD_MODULE_PROPERTIES
};
/* implement standard "stub" routine to introduce ourselves to Zend */
#if COMPILE_DL_FIRST_MODULE
ZEND_GET_MODULE(coreSO)
#endif
/* implement function that is meant to be made available to PHP */
ZEND_FUNCTION(first_module)
{
long parameter;
if (zend_parse_parameters
(ZEND_NUM_ARGS() TSRMLS_CC,
"l", ¶meter) == FAILURE)
return;
RETURN_LONG(parameter);
}
ZEND_FUNCTION(cs_get_map)
{
/* my code
*/
.
.
.
}
ZEND_FUNCTION(cs_get_stats)
{
/* my other code
*/
.
.
.
}
[/SNIP---------------------------------------------]
Like I said, I tried before with function names like this:
csGetMap
cdGetStats
It didnt work until I made them lower case.
(Note - I added the underscores to the names to aid
readability after I deleted the capital letters from the
function names)
Something to do with zend internals. Its probably documented
somewhere but I couldnt easily find it. Its just the sort of "gotcha"
that I thought would be useful in this forum.
I hope that saved someone some trouble. ;)
spsuhas at yahoo dot com
22-Jun-2003 08:23
If you want to write extension for windows system, Take a look at this article
It works!
Suhas
Ed a PHP enthusiast from NYC
28-Apr-2003 05:55
Thank you very much for the comments above!
Here is a distillation of how to compile your module as a dynamic library, placing it in your web server and loading it in your test .php file being served (PHP 4.3.1).
*** Compiling a module as a .so
$ cd ext/mystuff
$ cc -fpic -DCOMPILE_DL_MYSTUFF=1 -I/usr/local/include -I../../TSRM -I../.. -I../../main -I../../Zend -I../../ext/bcmath/libbcmath/src -c -o mystuff.o mystuff.c
$ cc -shared -L/usr/local/lib -rdynamic -o mystuff.so mystuff.o
*** Move it to the web server (doc root is /www)
$ cp mystuff.so /www/.
$ chmod 644 /www/mystuff.so
*** load the module in the .php file for testing purposes
<?
dl('/mystuff.so');
?>
The other thing that threw me off my tracks is that when dealing with strings you can allocate memory with emalloc and return the result with the RETURN_STRING macro (duplicate set to 0) and presumably PHP will take care of the efree -- or else I got it wrong and have plenty of leaks ;-)
17-Apr-2003 06:08
Compiling Manually NOTE:
remenber add -DHAVE_CONFIG_H flag
otherwise you .so can't be ld. then you cp it to php modules directory.
i.e
Compiling cc -fpic -DHAVE_CONFIG_H -I/usr/local/include -I. -I.. -I../Zend -c -o <your_object_file> <your_c_file>
Mac M�hleisen
19-Mar-2003 07:55
To built the modules shipped with the source just cd into the ext dir for example
cd ext/oci8
and type
export SHLIB_SUFFIX_NAME=so
phpize && aclocal && ./configure && make
now you have a subdir called "modules" with the .so file. Copy it to your extension dir and set everything up in php.ini.
This way you can add extensions to binary distributions like RPMS.
wish I didn't have to use PHP
12-Oct-2002 04:00
The example source has "#if COMPILE_DL_FIRST_MODULE", while the example compilation commands have "-DCOMPILE_DL=1".
Those constants should be the same for everything to work properly; i.e., I'd suggest using "-DCOMPILE_DL_FIRST_MODULE=1" in the compile command.
| |
PHP's Automatic Build System
