Error handling with PHP example.

error.php

<?php

// Setup
set_time_limit(3);

// http://php.net/manual/en/function.register-shutdown-function.php
function shutdown() {
    global $start;
    $elapsed=microtime(true) - $start;
    echo "SHUTDOWN. Time: ${elapsed}";
    var_dump(error_get_last());
}
register_shutdown_function("shutdown");

// http://php.net/manual/en/function.set-error-handler.php
function error_handler($errno, $errstr, $errfile, $errline, $errcontext) {
    global $start;
    $elapsed=microtime(true) - $start;
    echo "ERROR HANDLER. Time: ${elapsed}";
    var_dump(get_defined_vars());
}
set_error_handler('error_handler', -1);


// Start "app"
global $start;
$start = microtime(true);

echo "Hi\n";
$begin=time();

// errors
echo $unknown; # force an error message
sleep(10); # CPU time suspended as wall time ticks (same as DB query?)
while (true) {} # force a PHP timeout
echo "Foo";

## Output
# 
# Hi
# ERROR HANDLER. Time: 3.1...
#   ["errstr"]=>
#   string(27) "Undefined variable: unknown"
# ...
# SHUTDOWN. Time: 13.4...
#   ["message"]=>
#   string(44) "Maximum execution time of 3 seconds exceeded"
# ...

#############
## References
# http://stackoverflow.com/questions/6217994/php-how-to-use-set-error-handler-to-properly-deal-with-all-errors-except-noti
# http://stackoverflow.com/questions/4410632/handle-fatal-errors-in-php-using-register-shutdown-function
# http://stackoverflow.com/questions/36621/set-error-handler-isnt-working-how-i-want-it-to-work
# http://stackoverflow.com/questions/236795/php-destructor-vs-register-shutdown-function
# https://github.com/panrafal/PHP-Error
# http://stackoverflow.com/questions/1900208/php-custom-error-handler-handling-parse-fatal-errors
# http://stackoverflow.com/questions/4657475/register-shutdown-function-what-is-best-practice
# http://www.mysqlperformanceblog.com/2008/05/20/apache-php-mysql-and-runaway-scripts/
# https://gist.github.com/jsjohnst/3297804
# http://stackoverflow.com/questions/1870125/how-to-avoid-blocking-indefinitely-when-using-a-php-script-to-update-a-db-table