[Caml-list] Dynlink and unsafe modules

[Caml-list] Dynlink and unsafe modules

[Luca Pascali]

Hi to the whole team.

I'm having a little trouble using Dynlink module:
I have created a binarycode library (.cma file) that contains some 
functions I need in the application.
By statically linking this library to the executable I do not get any 
error, all works fine and I can use this library.
What I want (or I should say "what I would like") to do is to 
dynamically link this library to the executable.

I would like to say that no other module in the executable refers to the 
library. Library functions are referred by binarycode objects (.cmo 
files) dynamically loaded on request.

Now calling the Dynlink.loadfile function on the library filename (after 
the Dynlink.init ()) I get the following exception:
Dynlink.Error("this object file uses unsafe features")

What does it mean? Which kind of mistake I can have done in the library 
source that can bring to this error?
At what kind of mistakes I should pay attention when I work with the 
Dynlink module?

I tried also to call the Dynlink.allow_unsafe_modules true function to 
bypass the problem that rises the exception.
What I got is that I didn't get this exception, but I got troubles with 
a simple function in witch I use the stat of Unix in a try ... with ... 
clause.
This try/with failed to recognise the Unix.Error (Unix.NOENT,_) execption.
If I do not call the Dynlink.allow_unsafe_modules true function, this 
try/with does not fails.

Thanks in advance to everyone can help me.

Luca Pascali

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Re: [Caml-list] Dynlink and unsafe modules

[Richard Jones]

On Fri, Apr 16, 2004 at 05:23:45PM +0200, Luca Pascali wrote:
> Now calling the Dynlink.loadfile function on the library filename (after 
> the Dynlink.init ()) I get the following exception:
> Dynlink.Error("this object file uses unsafe features")

This simply means that the library or module you are trying to load
does some unsafe stuff - typically it was compiled with the "-unsafe"
option to turn off bounds checking, or else it contains C code.

Try using the ocamlobjinfo (sometimes called objinfo) command to
display the internal structure of the library / module that you are
trying to load.

> I tried also to call the Dynlink.allow_unsafe_modules true function to 
> bypass the problem that rises the exception.
> What I got is that I didn't get this exception, but I got troubles with 
> a simple function in witch I use the stat of Unix in a try ... with ... 
> clause.
> This try/with failed to recognise the Unix.Error (Unix.NOENT,_) execption.
> If I do not call the Dynlink.allow_unsafe_modules true function, this 
> try/with does not fails.

Can you post a test case where this fails?

Rich.

-- 
Richard Jones. http://www.annexia.org/ http://www.j-london.com/
Merjis Ltd. http://www.merjis.com/ - improving website return on investment
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