http://www.tcl.tk/cgi-bin/tct/tip/7.html
http://www2.hawaii.edu/~chenx/alg/util/zg_timer.c
postgresql source code
http://social.msdn.microsoft.com/Forums/en-US/windowsgeneraldevelopmentissues/thread/80710f2b-25e7-43f6-a4b9-d8bad010ab04