On this page:
ffi-obj
ffi-obj?
ffi-obj-lib
ffi-obj-name
ctype-basetype
ctype-scheme->c
ctype-c->scheme
ffi-call
ffi-call-maker
ffi-callback
ffi-callback-maker
ffi-callback?
make-late-will-executor

7 Unexported Primitive Functions 🔗

Parts of the ffi/unsafe library are implemented by the Racket built-in '#%foreign module. The '#%foreign module is not intended for direct use, but it exports the following procedures (among others).

procedure

(ffi-obj objname lib)  ffi-obj?

  objname : bytes?
  lib : (or/c ffi-lib? path-string? #f)
Pulls out a foreign object from a library, returning a value that can be used as a C pointer. If lib is a path or string, then ffi-lib is used to create a library object.

procedure

(ffi-obj? x)  boolean?

  x : any/c
(ffi-obj-lib obj)  ffi-lib?
  obj : ffi-obj?
(ffi-obj-name obj)  bytes?
  obj : ffi-obj?
A predicate for objects returned by ffi-obj, and accessor functions that return its corresponding library object and name. These values can also be used as C pointer objects.

procedure

(ctype-basetype type)  (or/c ctype? #f)

  type : ctype?
(ctype-scheme->c type)  procedure?
  type : ctype?
(ctype-c->scheme type)  procedure?
  type : ctype?
Accessors for the components of a C type object, made by make-ctype. The ctype-basetype selector returns a symbol for primitive types that names the type, a list of ctypes for cstructs, and another ctype for user-defined ctypes.

procedure

(ffi-call ptr    
  in-types    
  out-type    
  [abi    
  save-errno?    
  orig-place?    
  lock-name    
  blocking?    
  varargs-after])  procedure?
  ptr : cpointer?
  in-types : (listof ctype?)
  out-type : ctype?
  abi : (or/c #f 'default 'stdcall 'sysv) = #f
  save-errno? : any/c = #f
  orig-place? : any/c = #f
  lock-name : (or/c #f string?) = #f
  blocking? : any/c = #f
  varargs-after : (or/c #f positive-exact-integer?) = #f
The primitive mechanism that creates Racket callout values for _cprocedure. The given ptr is wrapped in a Racket-callable primitive function that uses the types to specify how values are marshaled.

procedure

(ffi-call-maker in-types    
  out-type    
  [abi    
  save-errno?    
  orig-place?    
  lock-name    
  blocking?    
  varargs-after])  (cpointer . -> . procedure?)
  in-types : (listof ctype?)
  out-type : ctype?
  abi : (or/c #f 'default 'stdcall 'sysv) = #f
  save-errno? : any/c = #f
  orig-place? : any/c = #f
  lock-name : (or/c #f string?) = #f
  blocking? : any/c = #f
  varargs-after : (or/c #f positive-exact-integer?) = #f
A curried variant of ffi-call that takes the foreign-procedure pointer separately.

procedure

(ffi-callback proc    
  in-types    
  out-type    
  [abi    
  atomic?    
  async-apply    
  varargs-after])  ffi-callback?
  proc : procedure?
  in-types : any/c
  out-type : any/c
  abi : (or/c #f 'default 'stdcall 'sysv) = #f
  atomic? : any/c = #f
  async-apply : (or/c #f ((-> any) . -> . any) box?) = #f
  varargs-after : (or/c #f positive-exact-integer?) = #f
The symmetric counterpart of ffi-call. It receives a Racket procedure and creates a callback object, which can also be used as a C pointer.

procedure

(ffi-callback-maker in-types 
  out-type 
  [abi 
  atomic? 
  async-apply 
  varargs-after]) 
  (procedure? . -> . ffi-callback?)
  in-types : any/c
  out-type : any/c
  abi : (or/c #f 'default 'stdcall 'sysv) = #f
  atomic? : any/c = #f
  async-apply : (or/c #f ((-> any) . -> . any) box?) = #f
  varargs-after : (or/c #f positive-exact-integer?) = #f
A curried variant of ffi-callback that takes the callback procedure separately.

procedure

(ffi-callback? v)  boolean?

  v : any/c
A predicate for callback values that are created by ffi-callback.

procedure

(make-late-will-executor)  will-executor?

Creates a “late” will executor that readies a will for a value v only if no normal will executor has a will registered for v. In addition, for the BC implementation of Racket, normal weak references to v are cleared before a will for v is readied by the late will executor, but late weak references created by make-late-weak-box and make-late-weak-hasheq are not. For the CS implementation of Racket, a will is readied for v only when it is not reachable from any value that has a late will; if a value v is reachable from itself (i.e., through any field of v, as opposed to the immediate value itself), a “late” will for v never becomes ready.

Unlike a normal will executor, if a late will executor becomes inaccessible, the values for which it has pending wills are retained within the late will executor’s place.

A late will executor is intended for use in the implementation of register-finalizer.