The state is being saved from “bare” poly, and being reloaded into the same
environment (no complicated chains of states in my example). “Silently crash”
means exits without any output, even though the … section of my code includes
calls to print.
Here is a simple example:
First:
$ echo "val x = ref 10; PolyML.SaveState.saveState \"foo\";" | poly
generating my state file “foo”.
Then I write bar.ML:
````
fun die s = (TextIO.output(TextIO.stdErr, s ^ "\n");
OS.Process.exit OS.Process.failure)
fun write_to_file f =
let
val ostrm = TextIO.openOut f
in
TextIO.output(ostrm, "(* this is a file *)\n");
TextIO.closeOut ostrm
end
fun main() =
let
val (s,file) = case CommandLine.arguments() of
[s,file] => (s,file)
| _ => die ("Usage:\n "^CommandLine.name() ^
" state file")
in
PolyML.SaveState.loadState s;
print "Switched state successfully\n";
write_to_file file;
PolyML.use file
end
````
Then I compile with polyc:
$ polyc bar.ML
Then I try running a.out
$ ./a.out foo usefile
I get no output, an exit code of 1 and usefile hasn’t been created.
This is on macos (uname says “Darwin Kernel Version 16.7.0”), and with Poly/ML
5.6 Release.
Michael
On 30/8/17, 22:33, "David Matthews" <[email protected]> wrote:
How exactly are you saving the state you want to load? The problem is
that you can only load a saved state into the same executable as you
used to save it. The ultimate reason for this restriction is that the
saved state does not save any heap cells that are present in the
executable but instead saves their (relative) addresses. loadState will
raise an exception if the saved state does not match the executable.
By "silently crash" do you mean that it raises an exception that you are
not handling or is this something else?
David
On 30/08/2017 13:10, [email protected] wrote:
> If I have a program I’d like to compile with polyc that looks like
>
>
> fun main () =
> let
> val _ = PolyML.SaveState.loadState (hd (CommandLine.arguments()))
> in
> …
> end
>
> what, if anything can I put in the … and have it work?
>
> All I really want is what is effectively a sequence of calls to “use” in
that slot, but there seem to be many ways of generating executables that
silently crash.
>
> Michael
>
> _______________________________________________
> polyml mailing list
> [email protected]
> http://lists.inf.ed.ac.uk/mailman/listinfo/polyml
>
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