►The Racket Reference
►3 Datatypes
▼3.2 Numbers
3.2.1 Number Types
3.2.2 Generic Numerics
3.2.3 Flonums
3.2.4 Fixnums
3.2.5 Extflonums
►3.2.4 Fixnums
On this page:
3.2.4.1 Fixnum Arithmetic
fx+
fx-
fx*
fxquotient
fxremainder
fxmodulo
fxabs
fxand
fxior
fxxor
fxnot
fxlshift
fxrshift
fx=
fx<
fx>
fx<=
fx>=
fxmin
fxmax
fx->fl
fl->fx
3.2.4.2 Fixnum Vectors
fxvector?
fxvector
make-fxvector
fxvector-length
fxvector-ref
fxvector-set!
fxvector-copy
in-fxvector
for/  fxvector
for*/  fxvector
shared-fxvector
make-shared-fxvector
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3.2.4 Fixnums

 (require racket/fixnum)

The racket/fixnum library provides operations like fx+ that consume and produce only fixnums. The operations in this library are meant to be safe versions of unsafe operations like unsafe-fx+. These safe operations are generally no faster than using generic primitives like +.

The expected use of the racket/fixnum library is for code where the require of racket/fixnum is replaced with

(require (filtered-in
          (λ (name) (regexp-replace #rx"unsafe-" name ""))
          racket/unsafe/ops))

to drop in unsafe versions of the library. Alternately, when encountering crashes with code that uses unsafe fixnum operations, use the racket/fixnum library to help debug the problems.

3.2.4.1 Fixnum Arithmetic

procedure

(fx+ a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fx- a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fx* a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxquotient a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxremainder a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxmodulo a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxabs a) → fixnum?

  a : fixnum?
Safe versions of unsafe-fx+, unsafe-fx-, unsafe-fx*, unsafe-fxquotient, unsafe-fxremainder, unsafe-fxmodulo, and unsafe-fxabs. The exn:fail:contract:non-fixnum-result exception is raised if the arithmetic result would not be a fixnum.

procedure

(fxand a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxior a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxxor a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxnot a) → fixnum?

  a : fixnum?

procedure

(fxlshift a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxrshift a b) → fixnum?

  a : fixnum?
  b : fixnum?
Safe versions of unsafe-fxand, unsafe-fxior, unsafe-fxxor, unsafe-fxnot, unsafe-fxlshift, and unsafe-fxrshift. The exn:fail:contract:non-fixnum-result exception is raised if the arithmetic result would not be a fixnum.

procedure

(fx= a b) → boolean?

  a : fixnum?
  b : fixnum?

procedure

(fx< a b) → boolean?

  a : fixnum?
  b : fixnum?

procedure

(fx> a b) → boolean?

  a : fixnum?
  b : fixnum?

procedure

(fx<= a b) → boolean?

  a : fixnum?
  b : fixnum?

procedure

(fx>= a b) → boolean?

  a : fixnum?
  b : fixnum?

procedure

(fxmin a b) → fixnum?

  a : fixnum?
  b : fixnum?

procedure

(fxmax a b) → fixnum?

  a : fixnum?
  b : fixnum?
Safe versions of unsafe-fx=, unsafe-fx<, unsafe-fx>, unsafe-fx<=, unsafe-fx>=, unsafe-fxmin, and unsafe-fxmax.

procedure

(fx->fl a) → flonum?

  a : fixnum?

procedure

(fl->fx a) → fixnum?

  a : flonum?
Safe versions of unsafe-fx->fl and unsafe-fl->fx.

3.2.4.2 Fixnum Vectors

A fxvector is like a vector, but it holds only fixnums. The only advantage of a fxvector over a vector is that a shared version can be created with functions like shared-fxvector.

Two fxvectors are equal? if they have the same length, and if the values in corresponding slots of the fxvectors are equal?.

procedure

(fxvector? v) → boolean?

  v : any/c
Returns #t if v is a fxvector, #f otherwise.

procedure

(fxvector x ...) → fxvector?

  x : fixnum?
Creates a fxvector containing the given fixnums.

Example:

> (fxvector 2 3 4 5)

(fxvector 2 3 4 5)

procedure

(make-fxvector size [x]) → fxvector?

  size : exact-nonnegative-integer?
  x : fixnum? = 0
Creates a fxvector with size elements, where every slot in the fxvector is filled with x.

Example:

> (make-fxvector 4 3)

(fxvector 3 3 3 3)

procedure

(fxvector-length vec) → exact-nonnegative-integer?

  vec : fxvector?
Returns the length of vec (i.e., the number of slots in the fxvector).

procedure

(fxvector-ref vec pos) → fixnum?

  vec : fxvector?
  pos : exact-nonnegative-integer?
Returns the fixnum in slot pos of vec. The first slot is position 0, and the last slot is one less than (fxvector-length vec).

procedure

(fxvector-set! vec pos x) → fixnum?

  vec : fxvector?
  pos : exact-nonnegative-integer?
  x : fixnum?
Sets the fixnum in slot pos of vec. The first slot is position 0, and the last slot is one less than (fxvector-length vec).

procedure

(fxvector-copy vec [start end]) → fxvector?

  vec : fxvector?
  start : exact-nonnegative-integer? = 0
  end : exact-nonnegative-integer? = (vector-length v)
Creates a fresh fxvector of size (- end start), with all of the elements of vec from start (inclusive) to end (exclusive).

procedure

(in-fxvector vec [start stop step]) → sequence?

  vec : fxvector?
  start : exact-nonnegative-integer? = 0
  stop : (or/c exact-integer? #f) = #f
  step : (and/c exact-integer? (not/c zero?)) = 1
Returns a sequence equivalent to vec when no optional arguments are supplied.

The optional arguments start, stop, and step are as in in-vector.

An in-fxvector application can provide better performance for fxvector iteration when it appears directly in a for clause.

syntax

(for/fxvector maybe-length (for-clause ...) body ...)

syntax

(for*/fxvector maybe-length (for-clause ...) body ...)

 
maybe-length = 
  | #:length length-expr
  | #:length length-expr #:fill fill-expr
 
  length-expr : exact-nonnegative-integer?
  fill-expr : fixnum?
Like for/vector or for*/vector, but for fxvectors. The default fill-expr produces 0.

procedure

(shared-fxvector x ...) → fxvector?

  x : fixnum?
Creates a fxvector containing the given fixnums. For communication among places, the new fxvector is allocated in the shared memory space.

Example:

> (shared-fxvector 2 3 4 5)

(fxvector 2 3 4 5)

procedure

(make-shared-fxvector size [x]) → fxvector?

  size : exact-nonnegative-integer?
  x : fixnum? = 0
Creates a fxvector with size elements, where every slot in the fxvector is filled with x. For communication among places, the new fxvector is allocated in the shared memory space.

Example:

> (make-shared-fxvector 4 3)

(fxvector 3 3 3 3)

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