I am using Fedora 9, gcc 4.3.0, and boost 1.38.0. When I include <boost/date_time/posix_time/posix_time_types.hpp> I get the following errors /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:67: error: ‘::clock_t’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:68: error: ‘::time_t’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:71: error: ‘::clock’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:72: error: ‘::difftime’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:73: error: ‘::mktime’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:74: error: ‘::time’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:75: error: ‘::asctime’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:76: error: ‘::ctime’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:77: error: ‘::gmtime’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:78: error: ‘::localtime’ has not been declared /usr/lib/gcc/x86_64-redhat-linux/4.3.0/../../../../include/c++/4.3.0/ctime:79: error: ‘::strftime’ has not been declared How can I resolve them? Thanks