• Bastiaan Veelo (15/16) Jun 03 2019 When I test that on Windows, what seems to happen is that when
• Jonathan Marler (4/20) Jun 03 2019 It's funny because the name of the enum makes more sense than the

Bastiaan Veelo <Bastiaan Veelo.net> writes:

Currently[1], std.MmFile.Mode.readCopyOnWrite is documented as

 readCopyOnWrite, /// Read/Write existing file, copy on write

When I test that on Windows, what seems to happen is that when 
written to, memory is copied and the copy is no longer backed by 
a file. So changes are not persistent and I think this should be 
clarified in the documentation. This mode will not change the 
file, and Read/Write should actually be Read, I would think. But 
marking the file read-only will cause this to fail, as the file 
is actually opened Read/Write in the implementation, and I wonder 
whether it should be opened read-only instead. The implementation 
is platform-specific, so what works on one might not work on the 
other.

Any input on this?

Bastiaan.

[1] 
https://github.com/dlang/phobos/blob/841541fca9c8c0224f3d47ef11db219a9fa5e065/std/mmfile.d#L64

Jonathan Marler <johnnymarler gmail.com> writes:

On Monday, 3 June 2019 at 09:11:41 UTC, Bastiaan Veelo wrote:
 Currently[1], std.MmFile.Mode.readCopyOnWrite is documented as

 readCopyOnWrite, /// Read/Write existing file, copy on write

 When I test that on Windows, what seems to happen is that when 
 written to, memory is copied and the copy is no longer backed 
 by a file. So changes are not persistent and I think this 
 should be clarified in the documentation. This mode will not 
 change the file, and Read/Write should actually be Read, I 
 would think. But marking the file read-only will cause this to 
 fail, as the file is actually opened Read/Write in the 
 implementation, and I wonder whether it should be opened 
 read-only instead. The implementation is platform-specific, so 
 what works on one might not work on the other.

 Any input on this?

 Bastiaan.

 [1] 
 https://github.com/dlang/phobos/blob/841541fca9c8c0224f3d47ef11db219a9fa5e065/std/mmfile.d#L64

It's funny because the name of the enum makes more sense than the 
comment :)  readCopyOnWrite is pretty clear, but "Read/Write 
existing file, copy on write" is a bit confusing.