The first PHP extension that has a bit of effect

D/C + + to develop PHP extensions

I think for PHP developers, learning things very miscellaneous, and very much, of course, the development of PHP extension is also a must master skills, here worship Big Brother Bird (laruence) ~
Today to develop the first somewhat functional extension, the main function is to log the time before generating the log in the date part

#即使当前的时间，年-月-日 时：分：秒 时间戳.微妙数 [2015-05-19 20:39:32 1432039172.968199]

PHP extension Function Prelude

First, create the skeleton:

1. 进入php源码src/ext目录下面2. 运行./ext_skel --extname=mytest3. 进入src/ext/mytest/目录4. 在编写扩展的时候要先修改下config.me文件的10-12行，去掉前面的dnl注释，这个网上一搜一大把。

Declare the name of the PHP extension function to be written in the header file Php_mttest.h

PHP_FUNCTION(get_log_title);#PHP_FUNCTION是PHP内核中声明的一个宏#define PHP_FUNCTION ZEND_FUNCTION    //在文件src/main/php.h : 347行#define ZEND_FUNCTION(name) ZEND_NAMED_FUNCTION(ZEND_FN(name))//文件src/Zend/zend_API.h : 68行#define ZEND_FN(name) zif_##name//文件src/Zend/zend_API.h : 65行#define ZEND_NAMED_FUNCTION(name) void name(INTERNAL_FUNCTION_PARAMETERS)//文件src/Zend/zend_API.h : 67行#define INTERNAL_FUNCTION_PARAMETERS int ht, zval *return_value, zval **return_value_ptr, zval *this_ptr, int return_value_used TSRMLS_DC//src/Zend/zend.h : 290行

The above declaration function macro expands after:

void zif_get_log_title( int ht, zval *return_value, zval **return_value_ptr, zval *this_ptr, int return_value_used TSRMLS_DC)

Add a declaration of the Get_log_title function in the Zend_function_entry declaration in Mytest.c

const zend_function_entry logs_functions[] = {        PHP_FE(confirm_logs_compiled,   NULL)           /* For testing, remove later. */PHP_FE(get_log_title, NULL)        PHP_FE_END      /* Must be the last line in logs_functions[] */};#编写函数PHP_FUNCTION(get_log_title){    struct timeval tv;    time_t rawtime;    struct tm *timeinfo;    char *formatinfo;    time(&rawtime);    timeinfo = localtime(&rawtime);    gettimeofday(&tv, NULL);    spprintf(&formatinfo, 0, "[%4d-%02d-%02d %d:%d:%d %d.%d]", 1900 + timeinfo->tm_year, 1 + timeinfo->tm_mon, timeinfo->tm_mday, timeinfo->tm_hour, timeinfo->tm_min, timeinfo->tm_sec, tv.tv_sec, tv.tv_usec);    RETURN_STRING(formatinfo, 1);}

I want to see a macro return_string here.

#define RETURN_STRING(s, duplicate) { RETVAL_STRING(s, duplicate); return; }//文件src/Zend/zend_API.h : 635行#define RETVAL_STRING(s, duplicate) ZVAL_STRING(return_value, s, duplicate)//文件src/Zend/zend_API.h : 623行#define ZVAL_STRING(z, s, duplicate) do {\//文件src/Zend/zend_API.h : 577-583行，这个的作用其实是给一个string类型zval变量赋值const char *__s=(s);\zval *__z = (z);\Z_STRLEN_P(__z) = strlen(__s);\//设置zval字符串长度Z_STRVAL_P(__z) = (duplicate?estrndup(__s, Z_STRLEN_P(__z)):(char*)__s);\//设置zval字符串的值Z_TYPE_P(__z) = IS_STRING;\//设置zval字符串的类型为字符串} while (0)

Therefore, return_string (FormatInfo, 1) expands to:

do {const char *__s=(formatinfo);zval *__z = (return_value);//这里面的return_value估计是内核定义的，类似 zval *return_value;(*__z).value.str.len = strlrn(__s);//等价于__z->value.str.len(*__z).value.str.val = (1?estrndup(__s, (*__z).value.str.len):(char*)__s);(*__z).type = 6;}

Compiling tests

编译的时候需要安装好的php，比如我的php安装在/usr/local/php/目录下面cd mytest;//今日刚才编写的函数扩展目录/usr/local/php/bin/phpize //运行phpize，生成configure文件./configure --with-php-config=/usr/local/php/bin/php-config //configure，后面的--with-php-config会生成so文件到安装好的扩展目录，当然也可以不用加，声称之后手动copy过去make//有错误的话修正make install //运行之后会提示类似下面的内容#Installing shared extensions:     /usr/local/php/lib/php/extensions/no-debug-non-zts-20100525/#修改配置文件php.ini添加extension = mytest.so#测试php -r 'var_dump(log_get_title());'

Output the following, congratulations on your success.

[root@iforever logs]# php -r 'var_dump(get_log_title());' && datestring(39) "[2015-05-19 22:52:29 1432047149.755613]"2015年 05月 19日 星期二 22:52:29 CST

5/19/2015 10:54:38 PM

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