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November 2004
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2004.11.05 14:38 "Re: is libtiff thread-safe?", by Bob Friesenhahn
On Fri, 5 Nov 2004, Joris wrote: > > > 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