atomic-fixnum-decf place &optional fixnum-delta => new-value
atomic-fixnum-incf place &optional fixnum-delta => new-value
One of the specific set of places defined for low level atomic operations.
A fixnum, default value 1
The macro
atomic-fixnum-decf
is like
decf
(for fixnums only) and
atomic-fixnum-incf
is like
incf
(for fixnums only), except that they are guaranteed atomic for a suitable place.
place must be one of the places described in Low level atomic operations, or expand to one of them.
Both the value in the place and fixnum-delta must be fixnums. The arithmetic is done without checking for overflow.