How to determine the application ID in which the file is opened?

Question

C++ / C#

There is some application written in C++ that opens files in an associated application. The problem is that not all applications return a reference (identifier) ​​to the process.
How can you 100% find out the link?
And how can I find out if this file is open?

Searching through the titles of open windows comes to mind, but what's the best way to do this?

Thank you!

Answer 1

OS what?
On Linux and Linux-like: fuser, lsof | grep filename. Both (both fuser and lsof) work by scanning the tree in /proc/PIDs. Similarly, it is implemented.

Answer 2

Hmm, why should the application return, if it needs to be received programmatically, then the CreateProcess function takes the PROCESS_INFORMATION pointer as the last parameter, where it will place the pid, handle of the process, etc.

Answer 3

If I understand correctly, then to check if the file is open, you can call CreateFile with FILE_SHARE_MODE=0 and if the file is open somewhere, then the function should end with ERROR_SHARING_VIOLATION.

Answer 4

I need to know in advance whether the file is open or not. the file is on the server and in order not to download it again, a check is needed.