The use of learning error_reporting

Error_reporting in the use of PHP programming frequency, presumably everyone is very clear, this article introduces the usage of error_reporting, for everyone to learn the reference. If the parameter level is not specified, the current error levels are returned. The following items are possible values for level: 1 e_error2 e_warning4 e_parse8 e_notice16 e_core_error32 e_core_warning64 e_compile_error128 E_COMPILE_ WARNING256 e_user_error512 e_user_warning1024 e_user_notice2047 e_all2048 E_stricte_notice indicates that the general situation is not recorded, only if the program has an error condition, For example, attempt to access a nonexistent variable, or call the stat () function to view files that do not exist. E_warning are usually displayed, but do not interrupt the execution of the program. This is very effective for debugging. For example: Call Ereg () with a problematic regular representation. The e_error is usually displayed, and the program execution is interrupted. This mask cannot be traced to a memory configuration or other error. E_parse parse the error from the syntax. E_core_error is similar to E_error, but does not include errors caused by PHP core. E_core_warning similar to e_warning, but does not include PHP core error warnings. Error reporting for PHP There are many configuration settings in the php.ini file. You should have your own php.ini file set up and put it in the appropriate directory, as shown in the documentation for installing PHP and Apache 2 on Linux. When debugging a PHP application, you should know two configuration variables. The following are the two variables and their default values:display_errors = offerror_reporting = E_all By searching for them in the php.ini file, you can find the current default values for both variables. The purpose of the display_errors variable is obvious-it tells PHP if it shows an error. The default value is OFF. However, to make the development process easier, please set this value to on:display_errors = on The default value for the error_reporting variable is e_all. This setting shows all the information from bad coding practices to harmless prompts to errors. E_all is a bit too thin for the development process because it shows hints on the screen for small things (such as uninitialized variables), which can mess up the browser's output. I just want to see errors and bad coding practices, but don't want to see harmless hints. Therefore, replace the default value of error_reporting with the following values:error_reporting = e_all & ~e_notice Restart Apache and it's all set up. Next, you'll learn how to do the same thing on Apache. Error reporting on the server depends on what Apache is doing, and opening an error report in PHP may not work because there may be multiple versions of PHP on the computer. It is sometimes difficult to tell which PHP version Apache is using because Apache can only view one php.ini file. It is a security issue to not know which php.ini file Apache is using to configure itself. However, there is a way to configure PHP variables in Apache to ensure that the correct level of error is set. Also, it is best to know how to set these configuration variables on the server side to veto or preempt php.ini files, providing a higher level of security. When you configure Apache, you should have been exposed to the basic configuration in the http.conf file in/conf/httpd.conf. To do what has already been done in the php.ini file, add the following lines to httpd.conf, overwriting any php.ini files:php_flag display_errors onphp_value error_reporting 2039 This overrides the flags already set for display_errors in the php.ini file, as well as the value of error_reporting. A value of 2039 represents E_all & ~e_notice. If you prefer to use E_all, set the value to 2047. Again, you'll restart Apache. Next, you will test the error report on the server. About error_reporting () This function, it can be blocked to some error message, but the PHP core caused by the error, is not blocked, because the PHP core error will directly lead to PHP file compilation failure, because the writing format is not written according to the Code rules of PHP errors caused by , is not blocked. * For now, avoid warnings of e_strict mode * (This must is done before function definitions) */ if (defined (' e_strict ')) { $old _error_reporting = error_reporting (0); if ($old _error_reporting & e_strict) { Error_reporting ($old _error_reporting ^ e_strict); } else { Error_reporting ($old _error_reporting); } unset ($old _error_reporting); Copy Code The following are common: Turn off all error reporting; error_reporting (0); Report easy running errors; reporting a simple run error Error_reporting (E_error | e_warning | E_parse); Reporting E_notice can good too (to report uninitialized Variables or catch variable name misspellings ...); Includes spelling errors that report some uninitialized variables or catch variable names Error_reporting (E_error | e_warning | E_parse | E_notice); Report all errors except E_notice The default value set in php.ini; all errors are reported but not included E_notice Error_reporting (e_all ^ e_notice); Report All PHP errors (bitwise is used in PHP 3); reports all errors Error_reporting (E_all); Same as error_reporting (E_all); ibid. Ini_set (' error_reporting ', e_all); Copy Code

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