I made an "interesting " mistake today that took some time to resolve, as so often happens. After building my program, converting src/foo.cbl to lib/foo.so, I did this $ cobc lib/foo.so instead of $cobcrun lib/foo The result? No error message, but a new file, ./foo.so, with many missing symbols. I suspect the technical answer is that a single .so file is valid input to the toolchain invoked by cobc. I'd accept that, maybe, if the result was not broken by every measure that a user would apply: 1. no message 2. output that does basically nothing I suggest that if the input is a single .so, the compiler should reject it as an error. I can think of no case in which that input would produce a useful output. --jkl