Re: [Caml-list] Suggested way to determine platform specific capabilities in build system?

[Thomas Gazagnaire <thomas@gazagnaire.org>]

>> What is the current suggested way to determine what, roughly, autoconf
>> would do for you? I have some platform specific functionality to be
>> included (or excluded) depending on the OS.
> 
> I don't know if there's a suggested way but here are various ways to proceed.
> 
> If you are using ocamlbuild, you can use `Sys.win32` since 4.01.0 or `Sys.os_type = "Win32"` to determine if you are on windows and otherwise get the (stripped and lowercased) result of `uname -s`, see e.g (but it's missing the win bit):  
> 
> https://github.com/dbuenzli/tsdl/blob/master/myocamlbuild.ml#L6
> 
> If you are using Makefiles you may want include `$(ocamlc -where)/lib/ocaml/Makefile.config` and use the `$SYSTEM` variable.
> 
> If this is only needed for C stubs you can also try solve this at the CPP level — but I guess this can be quite brittle — see e.g (here again missing the win bit as it's undefined for now):  
> 
> https://github.com/dbuenzli/mtime/blob/master/src-os/mtime_stubs.c#L11-L21
> 
> In any case make sure the value can be overridden from the command line for cross compilation scenarios.  

See also the system detection functions in opam-depext:

https://github.com/ocaml/opam-depext/blob/master/depext.ml#L76

Thomas