Publishing extension information

Extensions can publish information asked by phpinfo() or the Reflection API. Let’s see that together.

This chapter won’t be too long as there is really no difficulty.

MINFO() hook

Everything takes place in the MINFO() hook you declared, if you declared one. If you declared none, then the engine will run a default function to print information about your extension. That function will only print the version of your extension and the INI entries you eventually declared. If you want to hook into such process, you must declare an MINFO() hook in your extension structure.


Everything takes place in ext/standard/info.c , you may read that file. Printing information about PHP extensions is done by the engine by calling php_info_print_module()

Here is a simple MINFO() example:

#include "php/main/SAPI.h"
#include "ext/standard/info.h"

#define PIB_TXT  "PHPInternalsBook Authors"
#define PIB_HTML "<h3>" PIB_TXT "</h3>"

    time_t t;
    char cur_time[32];

    php_asctime_r(localtime(&t), cur_time);

        php_info_print_table_colspan_header(2, "PHPInternalsBook");
        php_info_print_table_row(2, "Current time", cur_time);

        if (!sapi_module.phpinfo_as_text) {
            php_write(PIB_HTML, strlen(PIB_HTML));
        } else {
            php_write(PIB_TXT, strlen(PIB_TXT));

zend_module_entry pib_module_entry = {
    NULL, /* Function entries */
    NULL, /* Module init */
    NULL, /* Module shutdown */
    NULL, /* Request init */
    NULL, /* Request shutdown */
    PHP_MINFO(pib), /* Module information */
    "0.1", /* Replace with version number for your extension */

What you basically have to do is to deal with php_info_print_*() API, that allows to print into the output stream that is generated. If you want to print some raw information, a simple php_write() is enough. php_write() just writes what you pass as argument onto the SAPI output stream, whereas php_info_print_*() API does as well, but before formats the content using HTML table-tr-td tags if the output is expected to be HTML, or simple spaces if not.

Like you can see, you need to include ext/standard/info.h to access the php_info_print_*() API, and you will need php/main/SAPI.h to access the sapi_module symbol. That symbol is global, it represents the current SAPI used by the PHP process. The phpinfo_as_text field inform if you are going to write in a “Web” SAPI like php-fpm f.e, or in a “text” one, like php-cli.

What will trigger your MINFO() hook are :

  • Calls to userland phpinfo() function

  • php -i, php-cgi -i, php-fpm -i. More generally <SAPI_binary> - i

  • php --ri or userland ReflectionExtension::info()


Take care of the output formatting. Probe for sapi_module.phpinfo_as_text if you need to change between text and HTML formatting. You don’t know how your extensions’ infos will be called by userland.

If you need to display your INI settings, just call for the DISPLAY_INI_ENTRIES() macro into your MINFO(). This macro resolves to display_ini_entries().

A note about the Reflection API

The Reflection heavily uses your zend_module_entry structure. For example, when you call ReflectionExtension::getVersion(), the API just reads the version field of your zend_module_entry structure.

Same to discover functions, your zend_module_entry has got a const struct _zend_function_entry *functions member which is used to register PHP functions.

Basically, the PHP userland Reflection API just reads your zend_module_entry structure and publishes those information. It may also use your module_number to gather back information your extension registered at different locations against the engine. For example, ReflectionExtension::getINIentries() or ReflectionExtension::getClasses() use this.