为什么ocamlfind无法找到已安装的库（camlp4）

Question

我安装了OCaml库。为了证明我有这个：

$ ~/.opam/bin/opam install camlp4 
[NOTE] Package camlp4 is already installed (current version is 4.02+system). 

这：

$ ls `ocamlc -where`/camlp4* 
Camlp4.cmi  Camlp4Bin.cmx Camlp4Parsers Camlp4Top.cmi  camlp4fulllib.a  camlp4lib.a  camlp4o.cma camlp4orf.cma camlp4prof.cmx camlp4rf.cma 
Camlp4Bin.cmi Camlp4Bin.o Camlp4Printers Camlp4Top.cmo  camlp4fulllib.cma camlp4lib.cma camlp4of.cma camlp4prof.cmi camlp4prof.o 
Camlp4Bin.cmo Camlp4Filters Camlp4Top  Camlp4_config.cmi camlp4fulllib.cmxa camlp4lib.cmxa camlp4oof.cma camlp4prof.cmo camlp4r.cma 

但是当我尝试这一点，它无法识别该文件

$ ocamlfind query camlp4 
ocamlfind: Package `camlp4' not found 

如何启用它？

我~/.ocamlinit看起来是这样的：

let() = 
    try Topdirs.dir_directory (Sys.getenv "OCAML_TOPLEVEL_PATH") 
    with Not_found ->() 
;; 
#use "topfind";; 

Answer 1

机会是很好的，你忘了

eval $(opam config env) 

命令用来激活OPAM enviromnment。并且您正在尝试使用系统编译器进行编译，即系统软件包管理器安装的编译器