MQL5 file I/O — Are there official guarantees for I/O completion before a deadline?

[山本研太郎]

Hello,

I have reviewed the official MQL5 documentation for FileFlush, FileClose, FileMove, ExpertRemove, and OnDeinit, as well as Microsoft's documentation on Windows file caching and I/O cancellation.

I understand their documented basic behavior. However, I could not establish the following guarantees from the public documentation.

1. Worst-case execution time

Does MetaQuotes provide a guaranteed upper bound on the execution time of FileOpen, FileWriteArray, FileFlush, FileClose, and FileMove, including defined OS or storage-delay conditions?

2. Outstanding I/O and cancellation

After these MQL5 functions return, or after an EA is deinitialized, can any related file-data or metadata writes remain pending in the MT5 runtime, Windows, or storage device?

Is there a supported mechanism to cancel outstanding operations and verify their complete termination, rather than merely request cancellation?

3. Physical-write deadline guarantees

Is there any officially supported mechanism or guarantee ensuring that all physical writes associated with an EA's file operations, including already-started I/O, finish strictly before a specified deadline, with no related physical writes at or after that deadline?

If this cannot be guaranteed by MT5, could you identify the exact limits of MetaQuotes' guarantees and whether an official technical support channel can provide a build-specific written answer?

I am not asking for confidential implementation details. References to official specifications, supported environments, and explicit guarantee exclusions would be very helpful.

Thank you.

[Sky All]

https://www.mql5.com/ja/forum/472790