kqueue and determine if a file is still open

[Stephan Leemburg]

I'm using kqueue events to trigger certain programs. The programs run  
when a file is dropped into a certain directory. To avoid race  
conditions, I want to know if the newly created or modified files are  
still open by a process, so I can do what I need to do when no-one  
else is possibly working on the file. Is there a way, other than  
repeating the tricks in lsof, to find out if a file is still open  
from within a c program?

If not would a systemcall like sys_isopen(path, O_WRONLY), where the  
call returns the or-ed value of the openmodes and-ed with the actual  
parameter, not be usefull?

--
Stephan