At least I realized that under win32 you must use system() or exec() commands after forking, to create independent process. So, at first fork, then daemonize child process (close STDIN and STDOUT) and then use system() or exec() to call part of code. This work well in my case and I hope it will work well in yours.

Thanks to other monks who helped me to find out this problem.

Li Tin O've Weedle
mad Tsort's philosopher