function_exists性能成本

Question

Does anyone have any data about the computational cost of function_exists? I have this snippet:

if(function_exists('fastcgi_finish_request')) {
    fastcgi_finish_request();
}

It is needed only because the function doesn't exist in dev environment, but it will always exist in production. Since I need high efficiency (this script is called millions of times per day and must be as fast as possible), should I remove this check before deploying to production?

Answer 1

You need this function if sometimes this function may not exist.

You can remove this check and implement empty method function fastcgi_finish_request() {} in dev environment that does nothing.