Re: [Caml-list] Build number and date in OCaml?

[Jeremie Dimino <jdimino@janestreet.com>]

Hi Etienne,

On Tue, Apr 9, 2013 at 12:38 PM, Étienne André
<Etienne.Andre@univ-paris13.fr> wrote:
> I've been using OCaml for a couple of years, but without using any advanced
> feature; so my question may be a little naive.
> Is there any way to insert easily the current date and time of compiling, as
> well as, e.g., an incremental build number in an OCaml program?
> So that it is printed at runtime, e.g., in the program header.
>
> I quite stupidly used the Unix.gettimeofday() function before realizing that
> it is of course executed at runtime.
>
> Of course, I could do it using an external script that would modify the
> OCaml source code before compiling, but is there any native OCaml feature
> for achieving this in a cleaner manner?

I don't know of such a feature.  One thing you can do is to write a
small camlp4/ppx extension that will replace for instance BUILD_DATE
by the current date.

But I think the standard way to have the build date/number at runtime
is to generate a small file containing this information and link it
with the other units. If you don't want to recompile everything every
time the date changes, just make sure that the other units do not
depend on the implementation on this file (i.e. they must not see the
.cmx), or generate a C file instead of a .ml file.

Cheers,

-- 
Jeremie