Check File Created in C++ in Serial Port Program

Hi Friends,
Sorry for my English. I am working on Medical Device Project. I am new for C++. Get Data from Medical Device,Store into Local Drive and Convert file(s) from local Drive into Local Drive. My MFCDLL creates one file at a time.So How to create Multiple files using COM Port Program.I am using this MFCDLL in my C Share .Net Application.
C++ Method:
Method Name: Import(Portno, FilePath).
Return Value :1(When file created in the Local Drive).
Suppose,file doesn't create in the Path .Return value should 0(zero).
1) Method will check ,suppose file should create or Not.
2) We can't identify time interval of One file to another file (from Medical Device).
So how to Solve this Problem?
 


Thanks and Regards,
Lakshmi Narayanan.S