Programming PHP

The functions available to you are:
OnUpdateBool
OnUpdateInt
OnUpdateReal
OnUpdateString
OnUpdateStringUnempty
However, there may be cases where you want to check the contents of an INI setting
for validity before letting it be set, or there may be things you need to call to initialize
or reconfigure when one of these settings is changed. In those cases, you will have
to write your own change-handling function.
When you have a custom change handler, you use a simpler INI definition. In place
of STD_PHP_INI_ENTRY( ), as shown previously, use:
PHP_INI_ENTRY("foo.my_ini_setting", "0", PHP_INI_ALL, MyUpdateSetting)
The MyUpdateSetting( ) function can then be defined like this:
static PHP_INI_MH(MyUpdateSetting) {
int val = atoi(new_value);
if(val>10) {
return FAILURE;
}
FOO_G(value) = val;
return SUCCESS;
}
As you can see, the new setting is accessed via the char *new_value. Even for an integer,
as in our example, you always get a char *. The full PHP_INI_MH( ) prototype
macro looks like this:
#define PHP_INI_MH(name) int name(zend_ini_entry *entry, char *new_value, \
uint new_value_length, void *mh_arg1, \
void *mh_arg2, void *mh_arg3, int stage \
TSRMLS_DC)
The extra mh_arg1, mh_arg2, and mh_arg3 are custom user-defined arguments that you
can optionally provide in the INI_ENTRY section. Instead of using PHP_INI_ENTRY( ) to
define an INI entry, use PHP_INI_ENTRY1( ) to provide one extra argument, PHP_INI_
ENTRY2( ) for two, and PHP_INI_ENTRY3( ) for three.
Next, after either using the built-in change handlers or creating your own, find the
PHP_MINIT_FUNCTION( ) and add this after the ZEND_INIT_MODULE_GLOBALS( ) call:
REGISTER_INI_ENTRIES( );
In the PHP_MSHUTDOWN_FUNCTION( ), add:
UNREGISTER_INI_ENTRIES( );
In the PHP_MINFO_FUNCTION( ), you can add:
DISPLAY_INI_ENTRIES( );
This will show all the INI entries and their current settings on the phpinfo( ) page.
348 | Chapter 14: Extending PHP
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