Hi Guys, I am using VC6, boost-1.33.1, and I've compiled the regex lib mt-s and ms-sgd It works when I have used mt-s in the release, however, when it comes to the debug mode. Any regex call will prompt me a vc++ "debug error" From my program console, it shows Assertion failed: r == 1 << 8, file E:\boost_1_33_1_beta\boost_1_33_1 \libs\regex\build\../src/w32_regex_traits.cpp, line 108 and then the program terminated with "abnormal program termination" error message I've tested this by taken out all regex related variables, function calls. Then the debug version of my program works! Anybody know what this really mean? I wonder if this is because of the issue during lib compilation. HCan anyone please give me a helping hand? I am really appreciate yours help. Best regards, Kit