# Module Printexc.Slot

    module Slot: sig .. end

- Since 4.02.0

    type t = Printexc.backtrace_slot

    val is_raise : t -> bool

`is_raise slot` is `true` when `slot` refers to a raising point in the code, and `false` when it comes from a simple function call.

- Since 4.02

    val is_inline : t -> bool

`is_inline slot` is `true` when `slot` refers to a call that got inlined by the compiler, and `false` when it comes from any other context.

- Since 4.04.0

    val location : t -> Printexc.location option

`location slot` returns the location information of the slot, if available, and `None` otherwise.

Some possible reasons for failing to return a location are as follow:

- the slot corresponds to a compiler-inserted raise
- the slot corresponds to a part of the program that has not been compiled with debug information (`-g`)

- Since 4.02

    val format : int -> t -> string option

`format pos slot` returns the string representation of `slot` as `raw_backtrace_to_string` would format it, assuming it is the `pos`-th element of the backtrace: the `0`-th element is pretty-printed differently than the others.

Whole-backtrace printing functions also skip some uninformative slots; in that case, `format pos slot` returns `None`.

- Since 4.02