Kevin, yes the mutex around proj.4 is necessary in order to guarantee correct behaviour when several threads call proj.4 concurrently.
There are a few places in proj.4 where global variables are used. One of them is the pj_errno variable / pj_strerrno() function. There's an old discussion on the proj.4 mailing list about the issue : http://lists.maptools.org/pipermail/proj/2005-February/thread.html#1483 (and other following threads the same month) I'd note that a few things have evolved : since proj 4.7.0, there is a locking mechanism within proj.4 that protects the init cache and the gridlist. But the pj_errno and maybe other issues remain. Best regards, Even _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
