Hi guys, I have a static library in which I have included the boost regex header. This static library compiles fine with no errors. But then I want to use this static library in an MFC application I made. I keep getting the following linking error: error LNK2005: "public: static unsigned int __cdecl std::char_traits<unsigned short>::length(unsigned short const *)" (?length@?$char_traits@G@std@@SAIPBG@Z) already defined in msvcprtd.lib(MSVCP71D.dll) What is the problem and how can I solve it? Thanks -- This email is from Civica Pty Limited and it, together with any attachments, is confidential to the intended recipient(s) and the contents may be legally privileged or contain proprietary and private information. It is intended solely for the person to whom it is addressed. If you are not an intended recipient, you may not review, copy or distribute this email. If received in error, please notify the sender and delete the message from your system immediately. Any views or opinions expressed in this email and any files transmitted with it are those of the author only and may not necessarily reflect the views of Civica and do not create any legally binding rights or obligations whatsoever. Unless otherwise pre-agreed by exchange of hard copy documents signed by duly authorised representatives, contracts may not be concluded on behalf of Civica by email. Please note that neither Civica nor the sender accepts any responsibility for any viruses and it is your responsibility to scan the email and the attachments (if any). All email received and sent by Civica may be monitored to protect the business interests of Civica.