php error handling

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Error handling
Commonly used tips for debugging code
1. Check the error message and error line number
2. Breakpoint output debugging method
3. Output debugging method
Error type of php program
1. Running error
will not prevent the php script, but it will The intent of the script. An error message is output, but the php program will continue to run
2. Syntax errors
are the most common and relatively easy to fix, and will prevent the script from running. The most common one is the lack of the terminating semicolon
3. Logic error (the most troublesome)
Wrong run level
1. Attention Level
Basically nothing serious, you can use it normally
E_NOTICE Runtime prompt
2. Warning level
Part of the function fails, the script continues to execute
E_WARING Warning during runtime
3. Severe error level
Prevents the script from running
E_ERROR Fatal error
E_ALL All errors and warnings
Set error level
1 . Modify php.ini in the configuration file. The semicolon in each line means commenting out the line
Modify the error_reporting option
& means and
| means or
(wavy line~) means anything other than
Note:
Save a copy of the configuration file to be modified , or copy the option you want to modify and comment it out
Be sure to restart the apache server after modifying the configuration file
2. Make modifications in your own script ( Recommended)
error_reporting()
Note: The scope is limited to the script where it is located
Other error options
1. The display_errors option indicates whether to display error messages in the browser. If it is on, it means that the error message is displayed, but it needs to be displayed according to the setting of error_reporting. If it is set to off, it means that it will not be displayed at all
2. ini_get() is a function to obtain configuration information. Note that when using ini_get( option), be sure to add quotes to the option ini_get('display_errors')
3. ini_set('option name','value') temporarily sets the configuration options through the function, at the end of the script Valid when
4. ini_get_all() will obtain all information configurations (global_value represents the settings in php.ini, and local_value represents the local settings)
Log processing
log_errors: Whether to start logging
error_log: Where to store errors
1. Customization The error file location
2. Put it in the system log syslog
How to view the system log
My computer (right click)- 》Management-》Event Viewer -》In the application options
Steps to set the log
1. Display all errors Error_reporting=E_ALL
2. display_errors=off does not display error reports
3.log_errors=on Turn on the error log
4.error_log sets where your error log should be stored

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