what's going on with checksums?

t_white · ‎10-08-2003

I am using Compaq Visual Fortran v6.6 to manage several projects: a main program and several DLLs. I would like to be able to track changes to the program and DLLs by using the checksum information in the header, but must be missing a Project setting somewhere, because the checksum changes everytime I re-link, whether there was any change to the code or not. When I use WinDiff to compare the two copies of the DLL, it claims that they are identical, except for some changes in blanks. Anyone know what's going on here?

Steven_L_Intel1 · ‎10-08-2003

Is there perhaps a link date encoded in there somewhere?

Steve

t_white · ‎10-08-2003

I was hoping you could tell me how the checksum is generated. I, too, thought that maybe this was an issue with the date or time stamp being included in the checksum, but I don't see a project setting in documentation other than /RELEASE in the link step that even addresses checksums, so I am at a loss here. Since we are sharing projects between parts of the company, I was trying to find a way to use the checksum to verify that the resulting DLL was identical from a successive build, when there have been no changes to the source code of project settings. Any ideas?

Steven_L_Intel1 · ‎10-09-2003

You're talking about a checksum in the DLL itself, right? That would be written by the MS linker - we don't have anything to do with it. I'm not sure why you think there would be a project setting for it - it's a way of protecting the DLL against corruption.

Steve

t_white · ‎10-09-2003

Good point! I was thinking, for some reason, that both the compiler and linker were CVF products. But it makes sense that the MS linker would be used, since the ideas was to make Visual Fortran part of the suite of applications that can be used in the Visual Studio development environment. I will address my question to MS. Thanks for pointing me in the right direction.