Foreign.Funptr
val t : t Ctypes.typ
A type representation for a function pointer type with explicit lifetime management.
val t_opt : t option Ctypes.typ
This behaves like t
, except that null pointers appear in OCaml as None
.
val free : t -> unit
Indicate that the fptr
is no longer needed.
Once free
has been called any C calls to this Dynamic_funptr.t
are unsafe. Only call free
once the callback is no longer used from C.
Turn an OCaml closure into a function pointer that can be passed to C.
The function pointer returned by of_fun
should be deallocated by a call to free
once it is no longer in use. Failure to call free
is an error.
Alternatively, with_fun
encapsulates both allocation and deallocation.
Implementation detail: to avoid crashes, if free
is not called then the implementation will retain a reference to the OCaml closure and report a warning. See report_leaked_funptr
.
with_fun fn (fun fptr -> e)
- Turn an OCaml closure into a function pointer and perform simple life cycle management.
with_fun fn (fun fptr -> e)
will call free fptr
after e
completes.
with_fun
is not safe to use if the C function ptr fptr
may still be used after e
completes.