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From "Bill Stoddard" <b...@wstoddard.com>
Subject RE: c-client's thread-safeness
Date Fri, 16 Aug 2002 12:33:32 GMT
> > This is a particularly interesting case as Mark is pretty adamant
> > that strtok() and gethostbyname() should be thread-safe and the fact
> > that it isn't on most platforms doesn't persuade him to use
> > strtok_r() or gethostbyname_r() if available.  (Not that I disagree
> > with him here - these *should* be thread-safe calls.)
>
>     That is clearly wishful thinking -- strtok/gethostbyname are
>     legacy, non-reentrant APIs according to POSIX/SUSv3.
>
>     The problem with these APIs is that it is impossible to make
>     them reentrant.  Yes, you can solve half of the problem by
>     using thread-local storage in the legacy APIs.  But then they
>     are still not reentrant, just thread-safe.
>
>     For portable applications, there is only one choice -- use
>     those interfaces which are marked as reentrant and don't
>     assume that suddenly all vendors will provide thread-safe
>     implementations of non-reentrant APIs.  That simply won't
>     happen.
>
>     What's his problem with the reentrant APIs?  Is the cost of
>     transition too painful for him?
>
>     - Sascha

I believe the criterion for adding a library to our list of "known thread
safe libraries" must be that the libraries are both thread safe -and-
reentrant. My $.02.

Bill


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