Re: [xml] EXSLT random() function

[Rush Manbert <rush manbert com>]

Ralf Junker wrote:
> > > so apparently libexslt implementation might just be conformant, but
> > > as usual we takes patches ... But I don't see how you would seed in
> > > a truely random fashion while keeping the code portable.
> >
> > replying to myself, maybe we could just use 
> >   srand((unsigned int)time(NULL))
> > just before xsltRegisterExtModuleFunction ((const xmlChar *) "random", ...
> > in exsltMathRegister()
>
>
> Well possible, but calling srand() automatically can be disturbing - and hard to debug, if not known! - if a 
> special srand() was issued previously to run reproducable tests.
>
> Also, as far as I understand, calling srand() automatically is only required for external libxml libraries. 
> If linked into applications, they can just call srand() as they please.
>
> How about, therefore, adding a simple srand() wrapper function like (for example xmlsrand() or similar) which 
> applications can call to set the external library's random seed?
>
> Ralf 

If you're going to do something like this (which sounds like a good 
idea), then maybe you should also consider allowing connections for 2 
callback functions. One to seed the random number generator as the 
library user desires, and a second to generate a random number. There 
are many ways to generate random numbers (See the thread post by Roumen 
Petrov), some better than others. There are also many possible ways the 
library users might want to use them. Providing default behavior with 
the capability to override would be potentially useful.

Just my 2 cents.

- Rush