Php Exception Handling Technology, top-level exception Processor

Which of the following functions is used to define a top-level exception processor?
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:Copy codeThe Code is as follows: <meta http-equiv = "content-type" content = "text/html; charset = UTF-8"/> <? Php
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 HandlingCopy codeThe Code is as follows: <? Php
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.