FAQ

If you have any question, just edit the page and leave question here. We will answer it later.

Why pending forever?

1. Check whether the judge daemon is running. The process's name should be php or php.exe
2. If the daemon quits by itself, check your PHP log (default to syslog or Windows NT events log) for detail error messages.

What the difference between sandbox and ideone.com?

OJ currently supports two kinds of judge engine: sandbox and ideone.com. The following table describes the difference.

Judge	Supported OSes	Internet	Speed	Languages	Limits	Safe
sandbox	Linux only	Not required	Depends on your server load. Normally faster than ideone.com	C/C++ only	No	Yes, but it depends on the sandbox
ideone.com	Linux & Windows	Required	Depends on the internet conection and ideone.com's load.	40+	1000 submissions/month	Sure, no submissions will be executed on your server

What the difference between Linux and Windows for OJ

Since the developers are using Linux, OJ supports Linux better. We did only a few testings under Windows.

And, Windows doesn't support all the features we provide.