Php exception handling technology, top-level exception processor _ PHP Tutorial

Php exception handling technology, top-level exception processor. Set_exception_handler (My_exception) is the function used to define the top-level exception processor. here, My_expection is a developer-defined exception handling function, which is a top-level exception processor. only the function used to define the top-level exception processor is
Set_exception_handler ("My_exception ");
Here, My_expection is a developer-defined exception handling function, which is a top-level exception processor. only when there is no function in the program to handle exceptions can there be a top-level exception processor to handle exceptions, if the top-level exception processor is not defined, the system's default exception processor will handle the exception.

Example:

The code is as follows:

Set_exception_handler ("My_expection ");
Function My_expection (){
Echo "this is a top-level exception processor ";
}
Try {
Nohello ("hello ");
} Catch (Exception $ e ){
Throw $ e;
}
Function nohello ($ nohello ){
If ($ nohello = "hello "){
Throw new Exception ("hello cannot be entered ");
} Else {
Echo "input successful ";
}
}
?>

A question about PHP exception handling

The code is as follows:

Try {
$ A = 10/0;
} Catch (Exception $ e ){
Echo "throw an exception ";
}
?>

The above code does not output "throw an exception", but outputs the error message: Warning: Division by zero in ......

Note: The try block does not throw an exception, but is handled according to the default error handling mechanism of the system.

So whether an exception can be caught depends on whether an exception is thrown.

Set_exception_handler ("My_exception"); here, My_expection is a developer-defined exception handling function, which is a top-level exception processor and only...