danno@eleazar.dartmouth.edu (Danno) (02/22/91)
Archive-name: unix/programming/pikestyle/1991-02-19 Archive: cs.toronto.edu:/doc/programming/pikestyle.* [128.100.1.65] Original-posting-by: danno@eleazar.dartmouth.edu (Danno) Original-subject: Re: Optimizing for compile time? Reposted-by: emv@ox.com (Edward Vielmetti) atk@tigger.Colorado.EDU (Alan T. Krantz) writes: >I think (hope) the thread about optimizing compile time is a joke. It >has to be - honest. Who in their right mind, or for that matter, their >wrong mind, would optimize for compile time? Well, this isn't exactly ``optimizing'' for compilation, but it's something of an example. This comes from a collection of short essays on programming style by Rob Pike, called ``Notes on Programming in C.'' It is available from cs.toronto.edu via anonymous FTP; this and other useful programming tips are in either /pub/doc/programming, or some variation thereof. To quote: ``There's a little dance involving #ifdef's that can prevent a file being read twice, but it's usually done wrong in practice - the #ifdef's are in the file itself, not the file that includes it. The result is often thousands of needless lines of code passing through the lexical analyzer, which is (in good compilers) the most expensive phase.'' He is talking here about #include files that #include other files that you might have already included. How much do you need to worry about this? It depends on how loaded down the machine you're working on is: it might not matter if you have a workstation at your desk, but a lot of us often work on general-use UNIX machines that will have upwards of 30 users at a time, doing any number of things. A folklore question: What are good uses for lots and lots of spare 9-track write rings? I've just become a junior operator, and these things are proliferating at an alarming rate... -- Danno McKinnon | danno@eleazar.dartmouth.edu ---------------------+-------------------------------------------------- Computer programmer | ``Now get out of here, before someone drops & data librarian | a house on you, too!'' -- Glinda of the North