Re: crypt mutex

[Marius Vollmer]

Mikael Djurfeldt <address@hidden> writes:

> Kevin Ryde <address@hidden> writes:
>
>> While nosing around the crypt function, I wondered if it ought to have
>> a mutex, just in case two threads run it concurrently.
>
> We probably need a policy which regulates when to have and when to not
> have a mutex.
>
> Personally, I wouldn't like Guile to have everything thread-safe
> "under the hood".  That would be a terrible waste of resources.

Yes.  Also, what does 'thread-safe' mean, aynway?  (This question is
probably just a nother way to ask what you are asking...)  For
example, can lists be meaningfully made thread safe?

> [...]
>
> So, the policy needs to specify where the border between Guile and
> user responsibility goes.  In most cases, I would probably draw the
> line so that as much as possible of the responsibility is left to the
> user with the exceptions that 1. Guile should never segfault due to
> misuse in this respect, and, 2. Guile need to have enough thread
> safety so that it's reasonably convenient to write parallel programs.

Yes, exactly my view.  Also, I would broaden point 1 a bit: we should
also 'fix' functions that can not every be used in a threaded program
without mutexes around them.  Like libc getpwent.  They might not
segfault, but you can't use them anyway in a threaded program.

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