package ctypes

fn is the signature of the underlying OCaml function.

Handle to an OCaml function that can be passed to C for use in callbacks.

Each value of type t allocated by of_fun must be deallocated by calling free. Alternatively with_fun encapsulates both allocation and deallocation.

A type representation for a function pointer type with explicit lifetime management.

This behaves like t, except that null pointers appear in OCaml as None.

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.