这是一个php扩展的示例，主要介绍如何用C/C++快速开发一个php扩展。
基于php-7.0.33来编写扩展
# 下载php-7.0.33
$ wget https://www.php.net/distributions/php-7.0.33.tar.gz
# 解压
$ tar xzf php-7.0.33.tar.gz
$ cd php-7.0.33/ext
$ sh ./ext_skel --extname=example
如果输出如下内容代表生成php7 example扩展代码成功了
$ sh ./ext_skel --extname=example
Creating directory example
Creating basic files: config.m4 config.w32 .gitignore example.c php_example.h CREDITS EXPERIMENTAL tests/001.phpt example.php [done].
To use your new extension, you will have to execute the following steps:
1. $ cd ..
2. $ vi ext/example/config.m4
3. $ ./buildconf
4. $ ./configure --[with|enable]-example
5. $ make
6. $ ./sapi/cli/php -f ext/example/example.php
7. $ vi ext/example/example.c
8. $ make
Repeat steps 3-6 until you are satisfied with ext/example/config.m4 and
step 6 confirms that your module is compiled into PHP. Then, start writing
code and repeat the last two steps as often as necessary.
ext_skel是一个专门用来生成扩展代码的shell脚本，执行完之后会在ext目录下生成一个example目录，example目录下的文件如下：
drwxr-xr-x 3 work work 4096 Jul 30 21:32 .
-rw-r--r-- 1 work work 505 Jul 30 21:32 example.php
drwxr-xr-x 2 work work 4096 Jul 30 21:32 tests
-rw-r--r-- 1 work work 7 Jul 30 21:32 CREDITS
-rw-r--r-- 1 work work 0 Jul 30 21:32 EXPERIMENTAL
-rw-r--r-- 1 work work 2332 Jul 30 21:32 php_example.h
-rw-r--r-- 1 work work 5195 Jul 30 21:32 example.c
-rw-r--r-- 1 work work 362 Jul 30 21:32 config.w32
-rw-r--r-- 1 work work 398 Jul 30 21:32 .gitignore
-rw-r--r-- 1 work work 2120 Jul 30 21:32 config.m4
drwxrwxr-x 76 work work 4096 Jul 30 21:32 ..
用ext_skel工具生成的扩展默认是C文件；这里如果有面向对象的需求，可以将example.c重命名为example.cpp(mv example.c example.cpp)
修改ext/example/config.m4，打开--enable-example开关，config.m4文件中这--enable-example是被注释掉的。 注意：config.m4文件的注释符是dnl
dnl PHP_ARG_ENABLE(example, whether to enable example support,
dnl Make sure that the comment is aligned:
dnl [ --enable-example Enable example support])
改为：
PHP_ARG_ENABLE(example, whether to enable example support,
dnl Make sure that the comment is aligned:
[ --enable-example Enable example support])
用phpize工具根据config.m4文件生成configure文件
$ export PHP_HOME=you_php_home
$ $PHP_HOME/php/bin/phpize
如果输入类似下面的内容说明执行成功了
Configuring for:
PHP Api Version: 20151012
Zend Module Api No: 20151012
Zend Extension Api No: 320151012
这时候当前目录下就会多出一些文件：
$ ls
acinclude.m4 autom4te.cache config.guess config.m4 configure config.w32 example.c EXPERIMENTAL ltmain.sh missing php_example.h tests
aclocal.m4 build config.h.in config.sub configure.in CREDITS example.php install-sh Makefile.global mkinstalldirs run-tests.php
其中比较重要的文件是configure，相信大家对这个文件应该不陌生，很多开源软件中都有这个文件。
执行configure生成example扩展so，先不着急我们看看configure文件都支持哪些参数：
$ ./configure --help
`configure' configures this package to adapt to many kinds of systems.
Usage: ./configure [OPTION]... [VAR=VALUE]...
To assign environment variables (e.g., CC, CFLAGS...), specify them as
VAR=VALUE. See below for descriptions of some of the useful variables.
Defaults for the options are specified in brackets.
Configuration:
-h, --help display this help and exit
--help=short display options specific to this package
--help=recursive display the short help of all the included packages
-V, --version display version information and exit
-q, --quiet, --silent do not print `checking ...' messages
--cache-file=FILE cache test results in FILE [disabled]
-C, --config-cache alias for `--cache-file=config.cache'
-n, --no-create do not create output files
--srcdir=DIR find the sources in DIR [configure dir or `..']
Installation directories:
--prefix=PREFIX install architecture-independent files in PREFIX
[/usr/local]
--exec-prefix=EPREFIX install architecture-dependent files in EPREFIX
[PREFIX]
By default, `make install' will install all the files in
`/usr/local/bin', `/usr/local/lib' etc. You can specify
an installation prefix other than `/usr/local' using `--prefix',
for instance `--prefix=$HOME'.
For better control, use the options below.
Fine tuning of the installation directories:
--bindir=DIR user executables [EPREFIX/bin]
--sbindir=DIR system admin executables [EPREFIX/sbin]
--libexecdir=DIR program executables [EPREFIX/libexec]
--sysconfdir=DIR read-only single-machine data [PREFIX/etc]
--sharedstatedir=DIR modifiable architecture-independent data [PREFIX/com]
--localstatedir=DIR modifiable single-machine data [PREFIX/var]
--libdir=DIR object code libraries [EPREFIX/lib]
--includedir=DIR C header files [PREFIX/include]
--oldincludedir=DIR C header files for non-gcc [/usr/include]
--datarootdir=DIR read-only arch.-independent data root [PREFIX/share]
--datadir=DIR read-only architecture-independent data [DATAROOTDIR]
--infodir=DIR info documentation [DATAROOTDIR/info]
--localedir=DIR locale-dependent data [DATAROOTDIR/locale]
--mandir=DIR man documentation [DATAROOTDIR/man]
--docdir=DIR documentation root [DATAROOTDIR/doc/PACKAGE]
--htmldir=DIR html documentation [DOCDIR]
--dvidir=DIR dvi documentation [DOCDIR]
--pdfdir=DIR pdf documentation [DOCDIR]
--psdir=DIR ps documentation [DOCDIR]
System types:
--build=BUILD configure for building on BUILD [guessed]
--host=HOST cross-compile to build programs to run on HOST [BUILD]
--target=TARGET configure for building compilers for TARGET [HOST]
Optional Features and Packages:
--disable-option-checking ignore unrecognized --enable/--with options
--disable-FEATURE do not include FEATURE (same as --enable-FEATURE=no)
--enable-FEATURE[=ARG] include FEATURE [ARG=yes]
--with-PACKAGE[=ARG] use PACKAGE [ARG=yes]
--without-PACKAGE do not use PACKAGE (same as --with-PACKAGE=no)
--with-libdir=NAME Look for libraries in .../NAME rather than .../lib
--with-php-config=PATH Path to php-config php-config
--enable-example Enable example support
--enable-shared=PKGS Build shared libraries default=yes
--enable-static=PKGS Build static libraries default=yes
--enable-fast-install=PKGS
Optimize for fast installation default=yes
--with-gnu-ld Assume the C compiler uses GNU ld default=no
--disable-libtool-lock Avoid locking (might break parallel builds)
--with-pic Try to use only PIC/non-PIC objects default=use both
--with-tags=TAGS Include additional configurations automatic
Some influential environment variables:
CC C compiler command
CFLAGS C compiler flags
LDFLAGS linker flags, e.g. -L<lib dir> if you have libraries in a
nonstandard directory <lib dir>
LIBS libraries to pass to the linker, e.g. -l<library>
CPPFLAGS (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
you have headers in a nonstandard directory <include dir>
CPP C preprocessor
Use these variables to override the choices made by `configure' or to help
it to find libraries and programs with nonstandard names/locations.
Report bugs to the package provider.
比较重要的参数是下面两个：
--with-php-config=PATH Path to php-config php-config
--enable-example Enable example support
执行下面几条命令生成example.so
$ ./configure --with-php-config=$PHP_HOME/php/bin/php-config --enable-example
$ make -j4
如果看到如下的输出就说明你example扩展已经编译成功了
Libraries have been installed in:
/home/liushuai06/work/php_source_code/php-7.0.33/ext/example/modules
If you ever happen to want to link against installed libraries
in a given directory, LIBDIR, you must either use libtool, and
specify the full pathname of the library, or use the `-LLIBDIR'
flag during linking and do at least one of the following:
- add LIBDIR to the `LD_LIBRARY_PATH' environment variable
during execution
- add LIBDIR to the `LD_RUN_PATH' environment variable
during linking
- use the `-Wl,--rpath -Wl,LIBDIR' linker flag
- have your system administrator add LIBDIR to `/etc/ld.so.conf'
See any operating system documentation about shared libraries for
more information, such as the ld(1) and ld.so(8) manual pages.
----------------------------------------------------------------------
Build complete.
Don't forget to run 'make test'.
执行完了之后，example.so位于modules目录下
$ ls modules
example.so
在php.ini文件末尾增加如下内容：
[example]
extension="example.so"
将编译好的example.so拷贝到php.ini文件中extension_dir配置的位置。 比如我的php.ini中extension_dir配置如下：
extension_dir="/home/work/php/ext"
则只需要将编译好的example.so拷贝到/home/work/php/ext目录
cp modules/example.so /home/work/php/ext
cd $PHP_HOME
$ php/bin/php --ri example
example
example support => enabled
如果执行php/bin/php --ri example，那么说明example扩展已经安装成功了。 当然我们还可以用源码中的example.php文件测试一下
$ $PHP_HOME/php/bin/php example.php
Functions available in the test extension:
confirm_example_compiled
Congratulations! You have successfully modified ext/example/config.m4. Module example is now compiled into PHP.
到现在为止，我们已经把扩展的架子搭好了，下来我们实现几个自定义的函数，然后在php中调用这些函数来给大家演示下如何在扩展中实现自己的函数。
在php_example.h文件 #endif /* PHP_EXAMPLE_H */ 行之前增加如下内容：
// 声明全局函数 求和
PHP_FUNCTION(example_sum);
// 声明全局函数 echo
PHP_FUNCTION(example_echo);
这里我们增加两个函数example_sum(求两个数之和)和example_echo(输出一个字符串)。
在example.c文件中增加如下内容：
/**
* @params double num1
* @params double num2
* @return double sum
* @bref
* 实现全局函数 example_sum
* */
PHP_FUNCTION(example_sum)
{
double num1,num2,sum;
if (zend_parse_parameters(ZEND_NUM_ARGS() TSRMLS_CC, "dd", &num1, &num2) == FAILURE) {
RETURN_FALSE;
}
sum = num1 + num2;
// RETURN_* 的定义在zend_API.h中
RETURN_DOUBLE(sum);
}
/**
* @params string
* @return string
* @bref
* 实现全局函数 example_echo
* */
PHP_FUNCTION(example_echo)
{
char *arg = NULL;
size_t arg_len, len;
zend_string *strg;
if (zend_parse_parameters(ZEND_NUM_ARGS(), "s", &arg, &arg_len) == FAILURE) {
return;
}
strg = strpprintf(0, "%.78s", arg);
RETURN_STR(strg);
}注册函数，同样函数修改example.c文件，找到example_functions定义的地方，然后注册example_sum和example_echo方法
/* {{{ example_functions[]
*
* Every user visible function must have an entry in example_functions[].
*/
const zend_function_entry example_functions[] = {
PHP_FE(confirm_example_compiled, NULL) /* For testing, remove later. */
PHP_FE(example_sum, NULL) /* register global example_sum function */
PHP_FE(example_echo, NULL) /* register global example_echo function */
PHP_FE_END /* Must be the last line in example_functions[] */
};
/* }}} */$ $PHP_HOME/php/bin/phpize
$ ./configure --with-php-config=$PHP_HOME/php/bin/php-config --enable-example
$ make -j4
生成的example.so在modules目录下，将其拷贝到对应的目录
cp -rf modules/example.so /home/work/php/ext
验证example扩展是否加载成功
$ $PHP_HOME/php/bin/php --ri example
编写php文件测试扩展函数功能，新建test_example.php文件内容如下：
<?php
$num1 = 1.1;
$num2 = 2.2;
var_dump(example_sum($num1, $num2));
$str = "hello world";
var_dump(example_echo($str));
执行test_example.php
$ $PHP_HOME/php/bin/php test_example.php
float(3.3)
string(11) "hello world"
如果输出如上内容，那么恭喜你，说明你已经测试通过啦，晚上给自己加个鸡腿吧！