2004.11.04 18:31 "[Tiff] is libtiff thread-safe?", by James Xu

2004.11.05 14:38 "Re: [Tiff] is libtiff thread-safe?", by Bob Friesenhahn

If the functions provided a pointer to user context then the error information could simply be stored there, without any need to use an OS-specific thread-API function to support thread-specific storage.

My point exactly. In other words, if the function were adequate... there would be not threading issue, nor any other issue of tracing back the error to its context, nor any other issue of storing the error description in the right place. In my view, that means the issue is not threading specific, not threading related.

Without threading, using a simple static variable to cache libtiff warnings/errors is sufficient.

Investigating the above quote the other way around now, the functions *not* providing a pointer to user context, the thread specific storage (threadvars or whatever) are *not* going to help you if the thread uses multiple TIFF *. It's still not possible in that case to trace back to user context.

Good point. However, in a single-threaded program, only one libtiff call can be active at a time, so it can still be made to work with some care.

In other words, threading is not related to this issue.

Of course threading is related to the issue, but the issues go beyond threading.

Bob

======================================
Bob Friesenhahn
bfriesen@simple.dallas.tx.us
http://www.simplesystems.org/users/bfriesen