Experience with a portable debugging tool

Debugging tools are usually highly machine and compiler dependent programs that are either impossible to move or require a tremendous effort to move to another machine. This paper describes Ctrace, a portable debugging tool for the C language that provides the same, easy-to-use debugging environment on all machines. A similar debugger can be written for any language. Ctrace is a preprocessor that inserts source language debugging code into the program before compilation that, at execution time, prints the text of each source language statement along with the values of variables it uses and modifies. Redundant trace output from program loops is detected and eliminated. Tracing can be limited to selected statements or functions. Ctrace has shown its usefulness and popularity by its installation on over 200, computers at Bell Laboratories. It has proven its portability by being used to test software on four different operating systems and nine different processors.