On Mon, Nov 28, 2016 at 03:39:05PM +0100, immanuel litzroth wrote:
> caml_invalid_argument(str) is no return and does not free it's
> argument.
> So calling it with a string constructed dynamically will mean it'll never
> get freed.
> I could construct an ocaml string and pass that to caml_raise_with_arg,
> but I don't seem to be able to get to the caml_exn_Invalid_argument from
> c. Am I missing something?

We have the same problem in libguestfs in a few places.  The solution
is to use an allocation on the C stack, either a fixed size buffer or
[although we don't currently use this] a variable sized one using
alloca.  The string is freed when the stack is unwound.  Examples:

https://github.com/libguestfs/libguestfs/blob/master/builder/yajl-c.c#L108-L114
https://github.com/libguestfs/libguestfs/blob/master/v2v/domainxml-c.c#L120

Be nice to have a "freeing" version of caml_raise* I suppose.

Rich.