scc@computer-lab.cambridge.ac.UK (Stephen Crawley) (01/06/88)
> I had a problem with 0915 a few times. The solution was to > select the Profile Tool, select "Apply" and Quit. For some strange > reason that I have not determined, it is sometimes necessary to > enter the Profile Tool before doing anything else. This sounds like an entirely different problem to me! What an 0915 code really means is "I've crashed ... debug me!" The trouble is that hardly anyone in the Interlisp community knows to use the Mesa debugger. So most people have to rely on guesswork. But why does the SystemTool crash so often anyway? My theory (for what it is worth) is that the root cause of the problem is in the Mesa programming language. In the Mesa language, a procedure's interface does not specify the exceptions that the procedure can raise. Therefore it is not possible to spot at compile time cases where an exception is raised but never caught. At runtime, when an exception is raised but not caught you get an 0915. What are the possible solutions? 1) Change the Mesa language? Politically impossible. 2) Find all the uncaught exceptions in SystemTool by hand? Impractical. Trouble is they'd need to wade through reams of Pilot and NS service stub code as well. 3) Everyone learns how to use Mesa debuggers? No way! Its all kind of sad really ... -- Steve