Core heap not available

Learning
1

Core heap not being available. I have installed Core and Core_kernel via opam.
“Core.Heap” is not available here.

open! Core
…
let pq = Heap.create ;;

Error :
24 | let pq = Heap.create ;;
^^^^^^^^^^^^^^^^
Error: Unbound module Heap

Command to compile : “ocamlfind ocamlc -package core -linkpkg heap_problems.ml”

“opam install core” output is as follows:
[NOTE] Package core is already installed (current version is v0.13.0).

Is heap support removed from Core or am I missing something basic?

2

My understanding is that Heap is now Pairing_heap, located
in a sublibrary (namely core_kernel.pairing_heap).

For some reason, we missed this move while preparing the
changelog for v0.13; sorry for the inconvenience.

1 Like
3

Thanks a ton. For future user following worked for me
“ocamlfind ocamlopt -linkpkg -package core_kernel.pairing_heap heap_problems.ml”

Is it possible to fix this documentation or raise a bug which fixes this?

1 Like
4

I ran into the same issue:

https://groups.google.com/forum/#!topic/ocaml-core/nMscbnfAf5Y

This post was helpful to me in figuring that out. Thanks @Rahul_Sr .

I noticed that Pairing_heap is missing from the API docs as well:

https://ocaml.janestreet.com/ocaml-core/latest/doc/core_kernel/Core_kernel/index.html

5

With a very simple program that simply uses printf I get that error:

$ ocamlfind ocamlc -package core -linkpkg hello2.ml
ocamlfind: [WARNING] Package `threads': Linking problems may arise because of the missing -thread or -vmthread switch
File "hello2.ml", line 1:
Error: Module `Condition' is unavailable (required by `Error_checking_mutex')
6

As suggested by the warning, try adding the flag -thread to the invocation. (It may also succeed if you invoke with -package threads.posix,core).

7

ah yes, that works, thx :slight_smile: