[I meant to add, I'm trying to see whether Gambit would work as an extension language to this environment: http://www.digitalspace.com/projects/lunar-telerobotics/. I used gambit 3.0 in a previous robotics simulation framework, and it worked very nicely. I'm hoping the lightweight threads in version 4 will be even better. - Mark] Marc, The sln files didn't work as is, but adding HAVE_STDIO_H;HAVE_ERRNO_H to the preprocessor definitions for the lib project was all that was needed. I ran through the tests. They basically work. There were minor problems, e.g., the file sizes of error.scm and newdir2/bbb changed, and there's something odd going on with the r4rstest.scm. (I can't get the test to work using the commandline as in tests/makefile.in, but running it by hand works fine.) Thank you very much to all who sent suggestions. If anyone wants the sln files, let me know, although they're exactly what Marc just sent plus the two preprocessor definitions above added to the lib project. A final question: has anyone used Gambit as an extension language for another program? Is there an example of building it as a dll or .so and making the call to initialize scheme? (I remember that being pretty easy in version 3, but so much has changed.) - Mark