In-depth explanation: PHP socket Communication

1. Common types of errors in PHP

1. Syntax Errors
* 1). Write fewer semicolons
* 2). 。 。。。。。

2. Environmental Errors
* 1). PHP Configuration Wait

3. Logic Error
* 1). To use an equal sign, the result uses two equal signs

2. Defined error types

Error name	Error Description
E_ALL	All errors and Reports
E_ERROR	Fatal run-time error, the execution of the script is
E_WARBING	Run-time warning (non-fatal), execution of script is not paused
E_PARSE	Compile-Time Parse error
E_NOTICE	Run-time Reminders
E_STRICT	Start PHP recommendations for code modifications to ensure optimal interoperability and forward compatibility of your code
E_DEPRECATED	runtime notifications, which will warn you about code that might not work in a future release
E_CORE_ERROR	Fatal error occurred during initialization of PHP startup
E_CORE_WARNING	A warning error (non-fatal) that occurred during initialization during PHP startup
E_COMPILE_ERROR	Compile-time fatal error
E_COMILE_WARNING	Compile-time warning (non-fatal error)
E_USER_ERROR	User-generated error messages
E_USER_WARNING	User-generated warning message
E_USER_NOTICE	User-generated reminder messages
E_USER_DEPRECATED	User-generated warning message, similar to e_deprecated, but generated by a trigger_error function
E_RECOVERABLE_ERROR	Can be caught indicating an error, she said that a very dangerous error may have occurred, but has not caused the PHP engine to be in an unstable state. If the error is not captured by the user's custom handle (see set_error_handler() ), it becomes a e_error, and the script terminates.

Error level in 3.php

1. Deprecated（不推荐|过时） Error
* 1). 最低级的错误For example ereg , using a function, mysql_escape_string
* 2).Deprecated: mysql_escape_string(): This function is deprecated; use mysql_real_escape_string() instead.

2. Notice Notification-level errors
* 1). To access undefined variables
* 2). When accessing an array, $arr ["name"]; The program first executes the lookup constant name, and if not found, the name is treated as a string

3. Warning Warning Level errors
* 1). Wrong number of parameters
* 2). Wrong parameter type

4. Fatal error fatal level of error （终止程序继续执行）
* 1). Invoke undefined function
* 2). Wrong parameter type

5. parse error Parsing Errors
* 1). The inspection phase did not pass, no other errors will be seen, because not yet where,程序还没解析成功

6. E_USER_相关的错误
* 1). The inspection phase did not pass, no other errors will be seen, because not yet where,程序还没解析成功

4. Error-related options in the PHP configuration file

Options	Description
Error_reporting	Set the level of error reporting
Display_error	Whether an error is displayed
Log_errors	Sets whether the resulting error message is logged or Error_log
Error_log	To set the save file for the error log
Log_errors_max_len	Set the maximum number of bytes for log_errors
Ignore_repeated_errors	Whether to ignore duplicate error messages
Ignore_repeated_source	Whether to ignore duplicate message sources
Track_errors	If this option is turned on, the last error will always be saved in the $php_errormsg

5. How to set the error level

1. Modify the value of error_reporting in the configuration file

2. In the code by error_reporting函数 setting the
* 1.error_reporting (0); Do not display errors except for E_parse
* 2.error_reporting (-1) | Error_reporting (E_all) Show All errors

3. Use Ini_set (' error_reporting ', 0) function runtime settings

6. Suppress Error output symbols @

1. @ Settype ()

7. PHP Error via Trigger_error

1. The ability to trigger errors is not limited to the PHP parser, but it can also trigger_error() trigger errors through functions.
2. Trigger_error (' Error message ', custom error, such as: (E_user_notice)) trigger_error (' Custom error message ', E_user_notice);
3. The function does not interrupt the program to continue execution.

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In-depth explanation: PHP socket Communication