CBFS Connect 2020 Python Edition

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on_close_file Event

Fires when the OS needs to close a file.


class CBFSCloseFileEventParams(object):
  def file_name() -> str: ...
  def delete_file() -> bool: ...
  def handle_info() -> int: ...
  def file_context() -> int: ...
  def handle_context() -> int: ...
  def result_code() -> int: ...
  def result_code(value) -> None: ...

# In class CBFS:
def on_close_file() -> Callable[[CBFSCloseFileEventParams], None]: ...
def on_close_file(event_hook: Callable[[CBFSCloseFileEventParams], None]) -> None: ...


This event fires when the OS needs to close the file specified by FileName. If the fire_all_open_close_events property is disabled, this event will only fire after the last handle to the specified file is closed.

To handle this event properly, applications can (if necessary/applicable) check to see if there are any other handles open for the file, and if not, close whatever backend resources are currently open for it.

The DeleteFile parameter indicates whether the file should be deleted; if it's True, the on_delete_file event will fire immediately after this event. The application may delete the file from either event handler.

The HandleInfo parameter carries a handle to an object with information about the file handle. While within the event handler, it can be used to call any of the following methods: get_handle_creator_process_id, get_handle_creator_process_name, get_handle_creator_thread_id, or get_handle_creator_token.

The FileContext and HandleContext parameters are placeholders for application-defined data associated with the file and specific handle, respectively. Please refer to the Contexts topic for more information.

The ResultCode parameter will always be 0 when the event is fired. If the event cannot be handled in a "successful" manner for some reason (e.g., a resource isn't available, security checks failed, etc.), set it to a non-zero value to report an appropriate error. Please refer to the Error Reporting and Handling topic for more information.

Note: The OS sends a file close request asynchronously, later than a process closes its handle(s) to the opened file. Due to this, the result code returned by the event handler does not get back to the process that closed the file handle.

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CBFS Connect 2020 Python Edition - Version 20.0 [Build 7880]