Module `Core__Syscall_result`

Representation of Unix system call results

Almost no Unix system call returns a negative integer in case of success.

We can use this to encode the result of a system call as either a positive integer value or -errno. This allows us to avoid exceptions for dealing with errors such as EAGAIN. Indeed, in some context we issue a system call in a tight loop that will often fail with EAGAIN and using exceptions to return it is costly.

type 'a t = private int

There is no [@@deriving sexp_of] on purpose as it could only print the 'a value as an integer. Use [%sexp_of: Int.t] or [%sexp_of: Unit.t].

exposed only as a performance hack

module type S : Core__.Syscall_result_intf.S with type 'a syscall_result := 'a t

module type Arg = Core__.Syscall_result_intf.Arg

module Make : functor (M : Arg) -> functor () S with type ok_value := M.t

module Int : S with type ok_value := int

module Unit : S with type ok_value := unit

val create_error : Core__.Unix_error.t -> _ t
val unit : Unit.t
val is_ok : _ t -> bool
val is_error : _ t -> bool
val error_exn : _ t -> Core__.Unix_error.t
val ignore_ok_value : _ t -> Unit.t: Keep only the error.