Usage of error_reporting() function in PHP (modify PHP shielding errors)

Syntax
error_reporting(report_level)
If the parameter level is not specified, the current error reporting level will be returned. The following are possible values ​​for level:
1 E_ERROR
2 E_WARNING
4 E_PARSE
8 E_NOTICE
16 E_CORE_ERROR
32 E_ CORE_WARNING
64 E_COMPILE_ERROR
128 E_COMPILE_WARNING
256 E_USER_ERROR
512 E_USER_WARNING
1024 E_USER_NOTICE
2047 E_ALL
2048 E_STRICT
E_NOTICE indicates that the normal situation is not recorded. It is only used when the program has an error situation, such as trying to access an unknown file. Existing variables, or call the stat() function to view files that do not exist.
E_WARNING is usually displayed but does not interrupt program execution. This is useful for debugging. For example: calling ereg() with the problematic regular notation.
E_ERROR is usually displayed and will interrupt program execution. This means that memory configuration or other errors cannot be traced using this mask.
E_PARSE Parses errors from syntax.
E_CORE_ERROR Like E_ERROR, but excludes errors caused by the PHP core.
E_CORE_WARNING Like E_WARNING, but does not include PHP core error warnings.
PHP Error Reporting
　 There are many configuration settings in the php.ini file. You should have already set up your php.ini file and placed it in the appropriate directory, as shown in the documentation for installing PHP and Apache 2 on Linux. There are two configuration variables that you should be aware of when debugging PHP applications. Here are the two variables and their default values: display_errors = Off
error_reporting = E_ALL
You can find the current default values ​​of these two variables by searching for them in the php.ini file. The purpose of the display_errors variable is obvious - it tells PHP whether to display errors. The default value is Off. However, to make the development process easier, set this value to On:
　　display_errors = On
　　The default value of error_reporting variable is E_ALL. This setting will show everything from bad coding practices to harmless tips to errors. E_ALL is a bit too granular for development purposes, as it also displays hints on the screen for small things (such as variables not being initialized), which messes up the browser's output. I only want to see errors and bad coding practices, but not harmless tips. So, please replace it with the following values The default value of error_reporting:
　　error_reporting = E_ALL & ~E_NOTICE
　 Restart Apache and everything is set. Next, you'll learn how to do the same thing on Apache.
　 Error reporting on the server
Depending on what Apache is doing, turning on error reporting in PHP may not work because there may be multiple versions of PHP on the computer. Sometimes it's hard to tell which PHP version Apache is using because Apache can only look at one php.ini document. Not knowing which php.ini file Apache is using to configure itself is a security issue. However, there is a way to configure PHP variables in Apache so that the correct error level is set.
Also, it’s a good idea to know how to set these configuration variables on the server side to override or preempt the php.ini file, thus providing a higher level of security.
When configuring Apache, you should have already been exposed to the basic configuration in the http.conf file in /conf/httpd.conf.
To do what you have already done in the php.ini file, add the following lines to httpd.conf, overwriting any php.ini files:
　　　php_flag display_errors on
　　php_value error_reporting 2039
　This Will overwrite the flags already set in the php.ini file for display_errors, as well as the value of error_reporting. The value 2039 represents E_ALL & ~E_NOTICE. If you prefer to use E_ALL, set the value to 2047. Again, you still need to restart Apache.
Next, we need to test the error reporting on the server.
Regarding the error_reporting() function, it can shield some error messages, but errors caused by the PHP core cannot be shielded, because errors caused by the PHP core will directly cause the PHP file compilation to fail, because the writing format does not Errors caused by writing according to PHP coding rules cannot be blocked

// Turn off all error reporting;关闭所有的错误 
error_reporting(0); 

// Report simple running errors;报告一个简单的运行错误 
error_reporting(E_ERROR | E_WARNING | E_PARSE); 

// Reporting E_NOTICE can be good too (to report uninitialized 
// variables or catch variable name misspellings …);包括报告一些未初始化的变量或捕捉变量名的拼写错误 
error_reporting(E_ERROR | E_WARNING | E_PARSE | E_NOTICE); 

// Report all errors except E_NOTICE 
// This is the default value set in php.ini;报告所有的错误但不包括E_NOTICE 这也是php.ini的缺省设置 
error_reporting(E_ALL ^ E_NOTICE); 

// Report all PHP errors (bitwise 63 may be used in PHP 3);报告所有的错误 
error_reporting(E_ALL); 

// Same as error_reporting(E_ALL);同上 
ini_set('error_reporting', E_ALL); 

The above introduces the usage of the error_reporting() function in PHP (modifying PHP to block errors), including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.