ocamlmklib 来救援。一步步:
$ ocamlc -verbose -c sillystubs.c
$ ocamlmklib -verbose sillystubs.o silly.mli -o silly
$ ocamlc -verbose silly.cma foo.ml -o foo
File "foo.ml", line 1, characters 0-1:
Error: Error while linking foo.cmo:
The external function `silly_silly' is not available
糟糕,您在 sillystubs.c 中定义了 caml_silly_silly,但在 silly.mli 中引用了 silly_silly(太傻了 :) 修复:
$ cat silly.mli
external silly : unit -> unit = "caml_silly_silly"
$ ocamlmklib -verbose sillystubs.o silly.mli -o silly
$ ocamlc -custom -verbose silly.cma foo.ml -o foo
/usr/bin/ld: cannot find -lsilly
collect2: ld returned 1 exit status
File "foo.ml", line 1, characters 0-1:
Error: Error while building custom runtime system
还是没有运气?添加-I.以查找所需的库。
$ ocamlc -I . -verbose silly.cma foo.ml -o foo.byte
$ ocamlc -I . -verbose -custom silly.cma foo.ml -o foo.byte.custom
$ ocamlopt -I . -verbose silly.cmxa foo.ml -o foo.native
但是在“真实”设置中,您确实想使用 ocamlfind 安装 silly 库,然后通过 ocamlfind 运行编译将放置所需的命令行选项,一切都会自动运行。从头开始,整个过程如下所示:
$ ocamlc -verbose -c sillystubs.c
$ ocamlmklib -verbose sillystubs.o silly.mli -o silly
$ cat META
version="0"
description="quite silly"
archive(byte)="silly.cma"
archive(native)="silly.cmxa"
$ ocamlfind install silly META silly.cm* *.mli *.a *.so
Installed /usr/local/lib/ocaml/3.11.2/silly/silly.a
Installed /usr/local/lib/ocaml/3.11.2/silly/libsilly.a
Installed /usr/local/lib/ocaml/3.11.2/silly/silly.mli
Installed /usr/local/lib/ocaml/3.11.2/silly/silly.cmxa
Installed /usr/local/lib/ocaml/3.11.2/silly/silly.cmi
Installed /usr/local/lib/ocaml/3.11.2/silly/silly.cma
Installed /usr/local/lib/ocaml/3.11.2/silly/META
Installed /usr/local/lib/ocaml/3.11.2/stublibs/dllsilly.so
Installed /usr/local/lib/ocaml/3.11.2/stublibs/dllsilly.so.owner
$ rm *.cm* *.a *.so *.o
$ ocamlfind ocamlopt -linkpkg -package silly foo.ml -o foo.native
$ ocamlfind ocamlc -custom -linkpkg -package silly foo.ml -o foo.byte.custom
$ ocamlfind ocamlc -linkpkg -package silly foo.ml -o foo.byte
本机和字节版本已准备就绪。顺便说ocamlc -custom一句弃用。
我希望揭开谜底。