[Cmake] How does CMake decide when and where to build .dsp files?

[Karr, David]

I have a program that has been built with Visual C++, and the 
developers want to continue using Visual C++ so we're stuck with
.dsw and .dsp files.  So I was very happy when I saw that
CMake will generate .dsw and .dsp, and I even got a small part of
the build environment apparently to come up (a workspace with one
of the projects).  But when I tried to add more of our projects
to the workspace, first Visual Studio complained that the .dsp file
wasn't generated by Studio, and after that, having tried various
things, I haven't seen any evidence that CMake creates any .dsp
at all--when I delete the .dsp and run CMake, there's still no .dsp,
and when I restore the original .dsp (created in Visual Studio)
and then run CMake with a CMakeLists.txt that is missing several
source files, those files still show up in my project when I
open the workspace.

In other words, it seemed my CMakeLists.txt was causing CMake to 
generate a .dsp, and then it mysteriously stopped doing so.
And I can't find any rules in the documentation that could
explain how this could happen.  (Of course it's obvious that it
happened when I fooled around with various filenames, options, 
and so forth, the problem is I have found no clue as to which of my
actions in particular might have done this, or how I can fix it
or prevent it from happening again.)

My other problem (which may be related) is the naming of the .dsp
files.  For reasons I'm still trying to figure out completely,
when it came to the second .dsp file, CMake initially created one 
with a name different than the .dsp that Visual Studio had been using.
How does CMake determine the name of the .dsp file that it will write?

David Karr