Is it possible in PHP to prevent “Fatal error: Call to undefined function”?

问题

In PHP, is there any way that I can ignore functions that are undefined instead of throwing a fatal error that is visible in the browser?—i.e., Fatal error: Call to undefined function

I know that there is the practice of wrapping all custom functions in a conditional as below, but is there a programmatic way to get this effect?

if (function_exists('my_function')) { 

   // use my_function() here;

}

回答1:

No. Fatal errors are fatal. Even if you were to write your own error handler or use the @ error suppression operator, E_FATAL errors will still cause the script to halt execution.

The only way to handle this is to use function_exists() (and possibly is_callable() for good measure) as in your example above.

It's always a better idea to code defensively around a potential (probable?) error than it is to just let the error happen and deal with it later anyway.

EDIT - php7 has changed this behavior, and undefined functions/methods are catchable exceptions.

回答2:

In php 7, this is now possible.

Example codez:

try {
    some_undefined_function_or_method();
} catch (\Error $ex) { // Error is the base class for all internal PHP error exceptions.
    var_dump($ex);
}

demo

http://php.net/manual/en/migration70.incompatible.php

Many fatal and recoverable fatal errors have been converted to exceptions in PHP 7. These error exceptions inherit from the Error class, which itself implements the Throwable interface (the new base interface all exceptions inherit).

回答3:

What you are asking for seems a little goofy, but you can get a similar effect by declaring all your functions as methods of a class and then implement __call as a method of that class to handle any undefined method calls. You can then handle calls to undefined methods however you like. Check out the documentation here.

回答4:

If you would like to suppress this error while working with objects use this function:

function OM($object, $method_to_run, $param){ //Object method
    if(method_exists(get_class($object), $method_to_run)){
        $object->$method_to_run($param);
    }        
}

Regards

回答5:

we can hide errors but this will log in apache error log

//Set display error true.

ini_set('display_errors', "0");

//Report all error except notice

ini_set('error_reporting', E_ALL ^ E_NOTICE ^ E_STRICT);

//We can use try catch method

try {
    my_method();
} catch (\Error $ex) { // Error is the base class for all internal PHP error exceptions.
    var_dump($ex);
}

//Check method existance

function_exists()

回答6:

Prevent no. But catch and log yes, using register_shutdown_function()

See PHP manual

function shutDown_handler()
{
   $last_error = error_get_last();
   //verify if shutwown is caused by an error
   if (isset ($last_error['type']) && $last_error['type'] == E_ERROR)
   {
      /*
        my activity for log or messaging
        you can use info: 
          $last_error['type'], $last_error['message'],
          $last_error['file'], $last_error['line']
          see about on the manual PHP at error_get_last()
      */
   }
}

register_shutdown_function ('shutDown_handler');

来源：https://stackoverflow.com/questions/7116995/is-it-possible-in-php-to-prevent-fatal-error-call-to-undefined-function

标签

php

error-handling

undefined

fatal-error