Cstubs
Operations for generating C bindings stubs.
module Types : sig ... end
module type FOREIGN = Ctypes.FOREIGN
Values of the errno_policy
type specify the errno support provided by the generated code. See ignore_errno
for the available option.
val ignore_errno : errno_policy
Generate code with no special support for errno. This is the default.
val return_errno : errno_policy
Generate code that returns errno in addition to the return value of each function.
Passing return_errno
as the errno
argument to Cstubs.write_c
and Cstubs.write_ml
changes the return type of bound functions from a single value to a pair of values. For example, the binding specification
let realpath = foreign "reaplath" (string @-> string @-> returning string)
generates a value of the following type by default:
val realpath : string -> string -> stirng
but when using return_errno
the generated type is as follows:
val realpath : string -> string -> stirng * int
and when using both return_errno
and lwt_jobs
the generated type is as follows:
val realpath : string -> string -> (stirng * int) Lwt.t
Values of the concurrency_policy
type specify the concurrency support provided by the generated code. See sequential
and lwt_jobs
for the available options.
val sequential : concurrency_policy
Generate code with no special support for concurrency. This is the default.
val unlocked : concurrency_policy
Generate code that releases the runtime lock during C calls.
val lwt_preemptive : concurrency_policy
Generate code which runs C function calls with the Lwt_preemptive module:
http://ocsigen.org/lwt/2.5.1/api/Lwt_preemptive
Passing lwt_preemptive
as the concurrency
argument to Cstubs.write_c
and Cstubs.write_ml
changes the return type of bound functions to include the Lwt
.t constructor. For example, the binding specification
let unlink = foreign "unlink" (string @-> returning int)
generates a value of the following type by default:
val unlink : string -> int
but when using lwt_preemptive
the generated type is as follows:
val unlink : string -> int Lwt.t
Additionally, the OCaml runtime lock is released during calls to functions bound with lwt_preemptive
.
val lwt_jobs : concurrency_policy
Generate code which implements C function calls as Lwt jobs:
http://ocsigen.org/lwt/2.5.1/api/Lwt_unix#TYPEjob
Passing lwt_jobs
as the concurrency
argument to Cstubs.write_c
and Cstubs.write_ml
changes the return type of bound functions to include the Lwt
.t constructor. For example, the binding specification
let unlink = foreign "unlink" (string @-> returning int)
generates a value of the following type by default:
val unlink : string -> int
but when using lwt_jobs
the generated type is as follows:
val unlink : string -> int Lwt.t
val write_c : ?concurrency:concurrency_policy -> ?errno:errno_policy -> Format.formatter -> prefix:string -> (module BINDINGS) -> unit
write_c fmt ~prefix bindings
generates C stubs for the functions bound with foreign
in bindings
. The stubs are intended to be used in conjunction with the ML code generated by write_ml
.
The optional argument concurrency
specifies the concurrency support provided by the generated code. The default is sequential
.
The generated code uses definitions exposed in the header file ctypes_cstubs_internals.h
.
val write_ml : ?concurrency:concurrency_policy -> ?errno:errno_policy -> Format.formatter -> prefix:string -> (module BINDINGS) -> unit
write_ml fmt ~prefix bindings
generates ML bindings for the functions bound with foreign
in bindings
. The generated code conforms to the FOREIGN
interface.
The optional argument concurrency
specifies the concurrency support provided by the generated code. The default is sequential
.
The generated code uses definitions exposed in the module Cstubs_internals
.