Hello all, while installing boost in a linux system i noticed a strange thing. i installed boost in two ways:- 1. in default directory (/usr/local) 2. by specifying a installation directory with "--prefix" option. (/usr/local/boost) the strange thing is that the result include files and library files in both the cases are different. and the files created with step 2 are throwing regex exception in a multithreaded environment. please can you help me in this ... Thanks & Regards Yogendra