mio file_size is incorrect

[spudwa]

I'm writing a large binary file with a struct/record size of 93k and at regular intervals I want to sort the tail of the file (1500 records) To speed up loading/sorting/writing I thought mmap could be the answer rather than fread() sort fwrite but I'm having a problem caused by Windows GetFileSizeEx() (I think) The following article explains why this may be happening

https://devblogs.microsoft.com/oldnewthing/20111226-00/?p=8813

I'm explicitly giving offset and length to the ctor but the error check fails and if I default the length argument the "wrong" file length is used.

As your documentation says mio can be used for shared access, this seems like a problem

Works fine without the check. I guess it's a case of whether you trust the input or not??? If input parameters are explicit who do you believe?