To compile checkers, run make -j4. You'll be given tons of warnings, unless they are fixed in testlib. Build should succeed though.

• char, ichar — Compares files character by character. Extremely strict, and therefore should rarely be used.
• token, itoken, exacttoken, iexacttoken — Compares files token by token, ignoring whitespace and line breaks.
• line, iline, exactline, iexactline — Compares files token by token, ignoring whitespace but not line breaks.
• yesno, exactyesno — Compares two sequences of YES and NO, case-insensitive.
• int, exactint — Compares two sequences of arbitrary-length signed integral numbers.
• intline, exactintline — Compares two sequences of arbitrary-length signed integral numbers, ignoring whitespace but not line breaks.
• float1 – float10 — Compares two sequences of real numbers. Absolute or relative error between corresponding elements must not exceed 10^-N.
• ok — A stub checker that always returns OK.
• fail — A stub checker that always returns FAIL.

Checkers prefixed with an i are case-insensitive.

Normal checkers return PE when encountered EOF in one file but not in another. Their exact counterparts return WA in such case.