2011.05.05 19:01 "Re: [Tiff] Is LibTiff 3.9.5 Thread Safe ?", by Bob Friesenhahn

That said, it is hopefully safe for different threads to operate on distinct TIFF objects at the same time.

There are some areas related to library initialization and error reporting which do not appear to be thread safe. If a bunch of threads requested to open different TIFF files all at the same time before the library has been exercised at least once, then failure is likely.

Bob
--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/