The error functions are used to deal with error handling and loging. The error functions allow us to define own error handling rules, and modify the way the errors can be logged.
The logging functions allow us to send messages directly to other machines, emails, or system logs. The error reporting functions allow us to customize what level and kind of error feedback is given.
| Function | Description |
|---|---|
| debug_backtrace() | Generates a backtrace |
| debug_print_backtrace() | Prints a backtrace |
| error_get_last() | Returns the last error that occurred |
| error_log() | Sends an error message to a log, to a file, or to a mail |
| error_reporting() | Specifies which errors are reported |
| restore_error_handler() | Restores the previous error handler |
| restore_exception_handler() | Restores the previous exeception handler |
| set_error_handler() | Sets user-defined error handler function |
| set_exception_handler() | Sets a user-defined exception handler function |
| trigger_error() | Creates a user-level error message |
| user_error() | Alias of trigger_error() |
| debug_backtrace() | Generates a backtrace |
Error handling is the process of catching errors raised by your program and then taking appropriate action. If you would handle errors properly then it may lead to many unforeseen consequences.
when there's a problem that prevents a script from running properly, the PHP engine triggers an error. Each error is represented by an integer value and an associated constant.
| Error Level | Value | Description |
|---|---|---|
E_ERROR |
1 |
A fatal run-time error, that can't be recovered from. The execution of the script is stopped immediately. |
E_WARNING |
2 |
A run-time warning. It is non-fatal and most errors tend to fall into this category. The execution of the script is not stopped. |
E_NOTICE |
8 |
A run-time notice. Indicate that the script encountered something that could possibly an error, although the situation could also occur when running a script normally. |
E_USER_ERROR |
256 |
A fatal user-generated error message. This is like an E_ERROR, except it is generated by the PHP script using the function trigger_error() rather than the PHP engine. |
E_USER_WARNING |
512 |
A non-fatal user-generated warning message. This is like an E_WARNING, except it is generated by the PHP script using the function trigger_error() rather than the PHP. engine |
E_USER_NOTICE |
1024 |
A user-generated notice message. This is like an E_NOTICE, except it is generated by the PHP script using the function trigger_error() rather than the PHP engine. |
E_STRICT |
2048 |
Not strictly an error, but triggered whenever PHP encounters code that could lead to problems or forward incompatibilities |
E_ALL |
8191 |
All errors and warnings, except of E_STRICT prior to PHP 5.4.0. |