I am using Windows 10 (64 bit) (1511, _not_ the anniversary update) and Excel 2010 (32 bit)

When I have a bit more time I will try to get to the bottom of what is causing Excel to crash in 2.29.

I will attempt to keep a history of versions by making copies of the mingw-w64 directory.

The compiler obviously changed from version 2.26 to 2.29.  Nothing in particular about how DLLs are created was changed.  I find it surprising, though, that a DLL is causing Excel to crash.  I'd ask if you could compile the DLL with some sort of debugging, but it sounds like you've moved on for the time being.

If you do have another version of GNU Fortran installed or present on the system, you can easily point Simply Fortran at it in the Compiler Options window.  For example, you could copy Simply Fortran 2.26's mingw-w64 directory somewhere else on your system, and then install Simply Fortran 2.29.  Once installed, the paths to the compilers can then be changed.

We don't have the facilities to ship different versions of GNU Fortran with Simply Fortran at this time.  Such a mechanism probably won't be added, unfortunately, so the above suggestion is the best solution, I'm afraid.

We do have many users who are always asking for the latest version.  Some have asked for in-development versions, in fact.  We always try to ship the latest, released version, implying that it has been tested for stability.  I understand there are reasons to stick with older versions, but we do have people asking for the other extreme (unreleased versions).  We're just trying to maintain a sensible policy.

I'll try to see what's occuring with the DLL crashing.  Could you tell me what OS and Excel versions you're running?

I have version 2.29 installed.

However, when using it to re-build one of my projects (a DLL for use with Excel), the resulting DLL now causes Excel to crash.

Originally this was built with 2.26 and worked.

So, I am going to try to uninstall 2.29 and re-install 2.26. I have no idea what the issue is and don't have much time to study this at the moment. (Edit: it worked when I reverted back to 2.26).

Have there been any changes to the way such DLL routines should be called in the later versions of the compiler? I am decorating the names manually.

It would also be good if we could have a facility for picking the version of gfortran we want to use. This would mean isolating different versions of gfortran in their own subdirectory's and all of the dependent library's as well. If this could be done it would be very valuable as it isn't always wise to just use the latest version of gfortran all the time.

Or could you provide some guidance on how this can be done.