Documentation for sub atomic-fetch-sub assembled from the following pages:

Class: atomicint §

From atomicint

(atomicint) sub atomic-fetch-sub §

Defined as:

multi sub atomic-fetch-sub(atomicint $ is rw, int $value)
multi sub atomic-fetch-sub(atomicint $ is rw, Int() $value)

Performs an atomic subtraction on a native integer. This will be performed using hardware-provided atomic operations. Since the operation is atomic, it is safe to use without acquiring a lock. Returns the value as seen before the subtraction was performed. Underflow will wrap around silently. If $value is too big to unbox to a 64-bit integer, an exception will be thrown. If $value otherwise overflows atomicint then it will be silently truncated before the subtraction is performed.