The four most commonly used ini functions in PHP configuration files_PHP tutorial

The configuration function of PHP is several ini_* functions, mainly for the operation of configuration files. In fact, there are four functions: ini_get, ini_set, ini_get_all, and ini_restore. Personally, the most useful ones are ini_set and ini_get.
* ini_get(): Get the option value of the configuration file
I believe many people have used this function, which is to get the value of an option in the configuration file. If it is a true value, it will return 1, if it is a false value, it will Returns 0, and a string returns a string.
For example, the example in the manual:
/*
Our php.ini contains the following settings:
display_errors = On
register_globals = Off
post_max_size = 8M
*/
echo 'display_errors = ' . ini_get('display_errors') . "n"; //Whether display errors is turned on
echo 'register_globals = ' . ini_get('register_globals') . "n ";//Whether global variables are turned on
echo 'post_max_size = ' . ini_get('post_max_size') . "n";//The maximum file size that can be submitted
echo 'post_max_size+1 = ' . (ini_get( 'post_max_size')+1) . "n";
?>

Output:
display_errors = 1
register_globals = 0
post_max_size = 8M
post_max_size+1 = 9
This function is mainly used to obtain the configuration file, which can facilitate many operations for you. For example, you want to operate string filtering, but you don’t know whether magic_quotes_gpc is turned on, so you can write a function like this:
/* String filtering function */
function stringFilter($str)
{
if (ini_get('magic_quotes_gpc)') {
return $str;
} else {
return addslashes($str);
}
}

Of course, if you have no way of knowing whether your global variable is open, you can also customize a function like this:
/* Variable detection function */
function getGetVar($var)
{
if (ini_set( 'register_gobals')) {
return $var;
} else {
return $_GET['var'];
}
}

Of course, you can do There are many uses, you can slowly experience them yourself.
* ini_set function: Set certain variable values ​​in php.ini
This function is to set the value in the option. It takes effect after the function is executed. When the script ends, this setting also becomes invalid. Not all options can be set by the function. The specific values ​​that can be set can be viewed in the manual for a list.
It is able to set the option value in php.ini. For example, the display_error option is turned off, but you want to display the error information in the program to facilitate your debugging the program, then you can use this function:
ini_set("display_errors" , "On");
Then the program on your page will display error information, and you can also use error_reporting to set the level of error information displayed.
If you need to increase the script execution time, you can set:
ini_set("max_execution_time", "180");
Then the script execution time will be changed from the default 30 seconds to 180 seconds. Of course, you It can also be set using set_time_limit().
In fact, it is very good if you combine ini_set and ini_get. For example, if you want to add your own include file path to the configuration file, but do you have permission to change php.ini, then you can combine two functions:
ini_set('include_path',ini_get('include_path').': /your_include_dir:');
* ini_get_all: Get all setting option variables
Return all option values ​​​​in the form of an array, which is convenient for you to use when phpinfo() cannot be used.
Manual example, such as:
$inis = ini_get_all();
print_r($inis);
?>

Partial output:
Array
(
[allow_call_time_pass_reference] => Array
(
[global_value] => 1
[local_value] => 1 [access] => 6
)
[allow_url_fopen] => Array
(
[global_value] => 1
[local_value] => 1
[access] => 7
)
...
)
* ini_restore: Restoring the default value of the configuration file
is to restore the default value of the configuration file. You can use it to restore after you use ini_set settings.