6 Miscellaneous Support
| (regexp-replaces objname substs) → string? |
| objname : (or/c string? bytes? symbol?) |
| substs : (listof (list regexp? string?)) |
A function that is convenient for many interfaces where the foreign
library has some naming convention that you want to use in your
interface as well. The objname argument can be any value
that will be used to name the foreign object; it is first converted
into a string, and then modified according to the given
substs list in sequence, where each element in this list is a
list of a regular expression and a substitution string. Usually,
regexp-replace* is used to perform the substitution, except
for cases where the regular expression begins with a ^ or
ends with a $, in which case regexp-replace is
used.
For example, the following makes it convenient to define Racket bindings such as foo-bar for foreign names like MyLib_foo_bar:
| (define mylib (ffi-lib "mylib")) |
| (define-syntax defmyobj |
| (syntax-rules (:) |
| [(_ name : type ...) |
| (define name |
| (get-ffi-obj |
| (regexp-replaces 'name '((#rx"-" "_") |
| (#rx"^" "MyLib_"))) |
| mylib (_fun type ...)))])) |
| (defmyobj foo-bar : _int -> _int) |
| (list->cblock lst type) → any |
| lst : list? |
| type : ctype? |
Allocates a memory block of an appropriate size, and initializes it
using values from lst and the given type. The
lst must hold values that can all be converted to C values
according to the given type.
| (vector->cblock vec type) → any |
| vec : vector? |
| type : type? |
Like list->cblock, but for Racket vectors.
| (vector->cpointer vec) → cpointer? |
| vec : vector? |
Returns a pointer to an array of _scheme values, which is the
internal representation of vec.
| (flvector->cpointer flvec) → cpointer? |
| flvec : flvector? |
Returns a pointer to an array of _double values, which is the
internal representation of flvec.
Returns the value most recently saved (in the current thread) after a
foreign call with a non-#f #:save-errno option (see
_fun and _cprocedure).
| (lookup-errno sym) → exact-integer? |
| sym : (or/c 'EINTR 'EEXIST 'EAGAIN) |
Returns a platform-specific value corresponding to a Posix errno
symbol. The set of supported symbols is likely to expand in the
future.
Converts v from a value matching from-type to a
value matching to-type, where (ctype-sizeof from-type)
matches (ctype-sizeof to-type).
The conversion is equivalent to
| (let ([p (malloc from-type)]) |
| (ptr-set! p from-type v) |
| (ptr-ref p to-type)) |
| (cblock->list cblock type length) → list? |
| cblock : any/c |
| type : ctype? |
| length : exact-nonnegative-integer? |
Converts C cblock, which is a vector of types, to a
Racket list. The arguments are the same as in the
list->cblock. The length must be specified because
there is no way to know where the block ends.
| (cblock->vector cblock type length) → vector? |
| cblock : any/c |
| type : ctype? |
| length : exact-nonnegative-integer? |
Like cblock->vector, but for Racket vectors.