Subject: [Announcement:] libefence
         Date: Thu, 15 Mar 2001 20:09:23 -0500
         From: Igor Markov <imarkov@umich.edu>
 Organization: U. of Michigan, EECS
   Newsgroups: umich.eecs.class.380

    I just noticed that CAEN Linux machines (e.g., red)
    have Electric Fence (efence) installed. This is a very neat
    debugging tool, and you could use it to find sneaky memory
    problems in your code. It is rarely finding anything that
    purify does not find, but I saw such cases. In addition, efence
    is free and comes with most Linux distributions. CAEN Linux systems
    should be able to compile/run your code just as well as Solaris systems,
    but you need to double check that your code runs on Solaris before you
    submit it.

    To use efence, you need to add  -lefence at the end of the line
    in your Makefile that creates executables. This will cause your
    program run much slower and use a lot more memory, but the main
    effect is that if something is wrong with memory accesses (such 
    as out-of-bounds array accesses or broken pointers), your program
    will seg. fault right away. Therefore, you need to run in gdb or ddd, 
    and you will know where the problems are.

    The main advantage of using efence is that it exposes "hidden"
    bugs that silently wreak havok in your program and lead to unexplicable
    seg. faults later on (those are very hard to debug). 

    AFAIK, you can't use efence and purify at the same time, but I haven't
    tried that with the latest versions.
    
-- 
   Igor Markov         (734) 936-7829       EECS 2211
   http://www.eecs.umich.edu/~imarkov