Find out if file was written using direct or sequential access

[jirina]

Is there a way how to find out if a binary file was written using direct or sequential access without opening it and reading values from it?

If I have to open the file and start reading values, how would I know that opened the file using an  access that is different from the one used to write the file?

Thank you in advance for any suggestions.

[Arjen_Markus · Accepted solution]

In the old days (let's say around 1980 thereabout) (some?) computer systems used to distinguish between direct-access and sequential-access, but nowadays there is no such difference anymore, at least not with current-day compilers and run-time systems that I am aware of.

There is a difference between binary and unformatted sequential files, but if your file is indeed binary (so no inherent record structure, as opposed to unformatted sequential files), then direct-access simply means a different way of positioning the read/write action within a file for all intents and purposes.

In fact, stream access should work fine even if the file was written as direct-access. (I know in the past some compilers might add some marker in the file to make sure the record length was correct, but that was years ago).

[jirina]

Thank you for pointing me in the right direction - the stream access works well for what I need to do, even for direct access written files.