(optimize {quality | (quality value)}*)
quality—an optimize quality.
value—one of the integers 0
, 1
, 2
, or 3
.
declaration or proclamation
Advises the compiler that each quality should be given attention according to the specified corresponding value. Each quality must be a symbol naming an optimize quality; the names and meanings of the standard optimize qualities are shown in Figure 3–25.
Name Meaning compilation-speed speed of the compilation process debug ease of debugging safety run-time error checking space both code size and run-time space speed speed of the object code Figure 3–25: Optimize qualities
There may be other, implementation-defined optimize qualities.
A value 0
means that the corresponding quality is totally
unimportant, and 3
that the quality is extremely important;
1
and 2
are intermediate values, with 1
the
neutral value.
(quality 3)
can be abbreviated to quality.
Note that code which has the optimization (safety 3)
,
or just safety,
is called safe code.
The consequences are unspecified if a quality appears more than once with different values.
(defun often-used-subroutine (x y) (declare (optimize (safety 2))) (error-check x y) (hairy-setup x) (do ((i 0 (+ i 1)) (z x (cdr z))) ((null z)) ;; This inner loop really needs to burn. (declare (optimize speed)) (declare (fixnum i)) ))
declare, declaim [Macro] , proclaim [Function] , Declaration Scope
An optimize declaration never applies to either a variable or a function binding. An optimize declaration can only be a free declaration. For more information, see Declaration Scope.