Computer SW Compilers - Berkeley CSUA MOTD
Berkeley CSUA MOTD:Computer:SW:Compilers:
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Berkeley CSUA MOTD
2017/09/20 [General] UID:1000 Activity:popular

2013/4/29-5/18 [Computer/SW/Languages/C_Cplusplus, Computer/SW/Compilers] UID:54665 Activity:nil
4/29    Why were C and Java designed to require "break;" statements for a
        "case" section to terminate rather than falling-through to the next
        section?  99% of the time poeple want a "case" section to terminate.
        In fact some compilers issue warning if there is no "break;" statement
        in a "case" section.  Why not just design the languages to have
        termination as the default behavior, and provide a "fallthru;"
        statement instead?
        \_ C did it that way because it was easy to program -- they just
        \_ C did it that way because it was easy to implement -- they just
           used the existing break statement instead of having to program
           a new statement with new behavior.  Java did it to match C.
           \_ I see.  -- OP
2017/09/20 [General] UID:1000 Activity:popular

2012/6/13-7/20 [Computer/SW/Compilers] UID:54417 Activity:nil
6/13    Hysterical:
2010/1/20-29 [Computer/SW/Compilers, Computer/SW/Languages/Misc] UID:53646 Activity:nil
1/20    Watch out for these Chinese hackers!!! Project Aurora has
        infiltrated into the U.S.
2009/8/31-9/9 [Computer/SW/Compilers] UID:53312 Activity:nil
8/31    I'm trying to learn ActionScript, like a step by step tutorial.
        The site at
        isn't well organized. It doesn't explain how to get started with
        an editor, compiler, IDE. And should I even learn AS2 when you can
        learn AS3? Is Adobe Flash CS4 >>> CS3 or just CS4 > CS3?
2009/7/21-24 [Computer/SW/Compilers, Computer/SW/OS/OsX] UID:53173 Activity:kinda low
        Read the Apollo 11 code comment. Bugless? Yeah right.
        \_ Who claimed that that code was bugless?
           \_ if it was bugless then astronauts wouldn't be necessary
              \_ They're not necessary except to do research. We don't need
                 them to fly anything.
                 \_ "Houston, we've had a problem"
                    \_ Wouldn't have been an issue at all if the astronauts
                       weren't up there to begin with. The O2 was for them.
2009/2/28-3/11 [Computer/SW/Compilers] UID:52661 Activity:nil
2/28    I'm looking for a recommendation of a compiler/IDE to use to
        develop C/C++ code under Linux. In school, we used jove/gcc and
        I still use emacs/vi and gcc to this day. However, it is really
        lacking. Under Windows I tried Visual Studio and there were some
        really nice things about it, although it was so overwhelming that
        after 6 months of occasional use I still didn't really know what I
        was doing. I don't need something that powerful. I would like a
        visual editor that allows me to compile from within, preferably
        with make. If it has a debugger, too, that's great but not a
        requirement. I'd like something simple and easy to learn/use. It
        doesn't have to be free, but that's a plus.
        Ones I have found: Eclipse , Anjuta , KDevelop, Code::Blocks
        Any experiences with these or others?
        \_ No opinions? This is the CSUA, right?
           \_ I've been using emacs + gcc as my development environment
              since the early 90s and I don't find it lacking and have
              been largely frustrated by IDEs (XCode, CodeWarrior, Visual
              Studio, &c.), so I can't really recommend anything to this
              poor poster.  My guess is that many people on the motd feel
              the same as me, hence the lack of responses.
           \_ emacs to edit source files then whatever IDE u want to compile
        \_ We use IDEA here, which is pretty good but I think Java specific.
           It's also a big resource hog. I tried Eclipse for a short while,
           it seems to do normal IDE things ok (e.g. jumping to method
           definitions, finding references to a method call, etc).
2008/11/17 [Politics/Domestic, Computer/SW/Compilers] UID:52028 Activity:nil
        meh.  lulz.
2008/6/13-20 [Computer/SW/Compilers, Computer/SW/OS/FreeBSD] UID:50257 Activity:nil
6/13    Anybody know of a library that can do the following in *BSD systems?
        Add a function call like "if (debug) print_backtrace()" and it
        would print out the stack trace.  Similar to setting a breakpoint
        in GDB and then doing "bt".  Running GDB is not an option sometimes.
2008/5/2-8 [Computer/SW/Compilers] UID:49874 Activity:low
5/2     How do I get the L1/L2 cache size and cache line size on my machine?
        Can I find this stuff out at compile time somehow?
        \_ You aren't planning on running your code on any other processors?
        \_ May I ask what it is you want to achieve ultimately? If you don't
           know your architecture and want to find out dynamically, there are
           tools that can peek/poke to give you definitive answers, plus you get
           to see the latency of L1/L2/memory and infer a lot of info like
           cache associativity. Prof Saavedra has done a lot of cache benchmarks
           and micro measurements.                              -kchang
           tools that can peek/poke to give you definitive answers, plus you
           get to see the latency of L1/L2/memory and infer a lot of info like
           cache associativity. Prof Saavedra has done a lot of cache
           benchmarks and micro measurements.                           -kchang
        \_ No, there isn't a simple way, compile time or not. Your common
           user oriented desktop compiler today doesn't know anything
           about L1/L2 besides knowing how to do proper register allocation
           and in most cases don't even do a good job of spilling, knowing
           about cache effects, etc. Now, there is a lot of research in
           the past 20 years where compilers for specialized applications
           will optimize vector computing, tight loops, unrolling based
           on known monotonicity of variables, specialization, and allocate
           memory access patterns all based on memory locality (L1/L2),
           but you're not going to get that type of optimization from
           gcc or M$ compiler.
           the past 20 years where compilers will optimize vector computing
           and allocate memory access patterns based on L1/L2, but you're
           not going to get that from gcc or M$ compiler.
           \_ That's unfortunate.  Is there some program I can run to find
              out?  /proc/cpuinfo tells me, "cache size : 4096 KB", but doesn't
              give L1, or line size.  Is that just the data cache?
              (This is an Intel Core2 )
        \_ What the hell does "at compile time" mean?
           \_ I mean, perhaps there is some built in constant I can use
              that gives the L2 cache size of the machine you're compiling on.
              \_ You mean for a POSIX C++ compiler?  Also do you not expect
                 your code to be run on any other machine?
                 \_ Nope, this is purely an optimization test for 1 machine.
                    I guess if there's a way to find out the sizes dynamically
                    that's ok too.
                    \_ What I'm saying is that "compile time" doesn't mean
                       shit.  Compile time + what language/compiler you are
                       using might mean something.
                       \_ Language: C, C++, or Fortran.  Not picky
                          Compiler: gnu, intel, or portland.  Not picky.
                          OS: Linux.
                    \_ If it's just for one machine, why don't you just look
                       up the specs at Intel or AMD's website?
                       \_ I think I'd have to know more about the CPU than I
                          do.  Also, it would be nice to be able to recompile
                          it on other machines for comparison.
                          \_ Then you probably want to look into a CPUID
                             utilities (or roll your own simple version if
                             you just want simple cache info), along with
                             preprocessing of some sort. However, cache size
                             and line size are spelled out pretty clearly in
                             specs, so you don't have to know all that much.
                          \_ Someone considerately overwrote my post here,
                             so to recap, look into a cpuid utility +
2007/11/30-12/6 [Computer/SW/Compilers, Computer/HW/CPU] UID:48719 Activity:moderate
11/29   From the CSUA minutes:
        - Next Gen Console
        -- If we have $1800 in our accounts, should we buy a console:
           4 votes passes.
        -- Console voting: 2 votes each, neither passes
           * 360 = 600, more games
           * PS3 = 650, not as many games
        Does this mean the CSUA already has a Wii?
        Since when is, "more expensive, fewer games" an argument for something?
        I guess if they're gonna install Linux and try some Cell development,
        THAT would be cool, but I don't think that's what they want it for.
        \_ Netrek is free.. but you need to have skills
        \_ I think the decision should be based on which you can hack and/or
           boot alternate OS's on.   I think there is a clear answer here...
           \- YMWTS: KYELICK et al paper "The potential of the cell processor
              for scientific computing" on the POWER of the CELL. Interesting
              and quick read. Note: KYELICK now the Director of NERSC.
              \_ Yeah, but Roadrunner (A combo Opteron/Cell cluster proposed
                 at Los Alamos) is still a dumb idea.
                 \_ Why do you say that?  I'd be more concerned about using
                    /panfs as the storage system. Panasas might be ok by the
                    time it is deployed. A lot of impressive people there,
                    but mixed experiences in practice.
                    \_ The Cell already has a perfectly good general processor
                       attached to it.  (A dual core power 5).  What's the
                       Opteron doing there?  The last thing the Cell
                       development tool kit needs is another totally different
                       processor to work with.  Yea! A third compiler!  For
                       hevean's sake, they don't even have the same endianness!
                       processor to work with.  Yeah! Another compiler!  For
                       hevean's sake, the don't even have the same endianness!
                       \- ibm and amd are working together on a few things
                          like socket compat between POWER-tng and Opteron,
                          and Torrenza(sp?)/HTX rather than PCIe. the HPC space
                          is very different from the rest of the world ...
                          on a $100m computer you have a legion of programers
                          to work on tweaking code, compilers because they
                          are no longer dominated by "expensive programmer
                          time costs".
                          \_ While everything you say is true, I can't see how
                             that excuses creating a totally wacky, needlessly
                             difficult architecture.  Even Los Alamos
                             doesn't have infinite resources, programmer time
                             still costs money, money Los Alamos doesn't have.
                             Not to mention, they're buying the whole machine,
                             whole hog.  No small test prototype.  On a totally
                             untestest architecture.
                             \- no offense intended here, but are you just
                                reading articles on the net or do you have
                                some experience with how large HPC procurements
                                are done? i dont have any specific knowledge
                                of Los Alamos/Roadrunner but two things dont
                                ring true: 1. los alamos being on the hook for
                                all the dev and tuning work 2. ibm just being
                                responsible for dropping the machine off at
                                the loading dock and being done ... the "whole
                                machine whole hog" part. usually there are
                                lots of partial milestones involved. although
                                the somewhat dirty not that secret part of
                                this is those milestones are never missed
                                with major consequences. [well maybe once,
                                but not with one of the main *hpc* vendors.
                                i cant mention which well known vendor it was].
                                \_ Sorry, I didn't mean to imply what you've
                                   read into the 'whole hog' statement.  I
                                   guess that was really poor word choice.  I
                                   just meant that Los Alamos didn't buy a
                                   small prototype cluster to see how well this
                                   thing will work in production, as is
                                   normally done.  I'm aware IBM has milestones
                                   and will support the cluster.
2007/2/18-20 [Computer/SW/Languages/C_Cplusplus, Computer/SW/Compilers] UID:45772 Activity:nil
2/18    Anyone have Richard Stallman's old .emacs config?
        \- why, you want to borrow some of his abbrev stuff?
           that about the main unique thing that was in there.
           well maybe some gdb stuff. --psb
           \_ the macros were pretty funny.  can you put a copy
              in /tmp?  ok thx.
2006/11/10-12 [Computer/SW/Compilers] UID:45316 Activity:nil
11/10   Is there anyway to get C/C++ compilers to automatically compile
        different code for different processors?  I'd like to be able to
        say something like:
          #if defined X86 ...
          #elif defined SPARC ...
          #else ...
        If there's not standard way to have the compiler do it, is ther an
        easy way to have configure figure it out?
        \_ Most compilers have something like that.  Which compiler are you
           \_ I have to support a couple. gcc and icc are the main ones.
           \_ So, do you know how to do it in any compiler?  Please?
        \_ Do you mean that you want to do this without the #if statements?  Or
           do you just want standardized OS defs?  If the latter, take a look a
           the wxwidgets project, it's got a lot of examples of OS-specific
           \_ I don't care about OS, I care about processor architecture.
              x86, sparc, IA64, PowerPC.  I don't really care if it's done
              with #ifdefs or some other way.  It doesn't matter.
              \_ Sorry--brain fart about OS.
         \_ gcc at least, makes this easy for you. do a 'gcc -E' and see what
            defines it sets. Usually it is thinkgs like __sparc__ and __X86__
            for the relevant architectures.  Then you can just wrap your code
             in #ifdef's for those symbols. -ERic.
2006/8/25-28 [Computer/SW/Languages, Computer/SW/Compilers] UID:44149 Activity:nil
8/25    Why are iterators "superior" or more recently popular over the
        traditional method of using  for loops and indexing?
        \_ I guess it's because you can change an array to some other data
           structure (linked-list, tree, ...) without changing the loop code.
           \_ This is a limitation of your language, not the concept of looping
        \_ They handle multithreaded use cases better.
           They hide implementation details.
           You can pass iterators around between functions and they do
           what you want witout much hassle.
        \_ Traditionally doing pointer comparisons is faster than
           dereferencing by index. (Good compilers probably will
           transform the latter for you for simple data structures like
           arrays, though.) Also, they're simply an abstraction that
           better describe what you're trying to accomplish
           (reverse_iterator) or what your needs are (const_iterator).
2006/8/7-11 [Computer/SW/Compilers] UID:43928 Activity:nil
8/7     OK all you compiler geniuses looking for a cool job:
        \_ Why do you keep posting this?
           \_ There must be no compiler geniuses reading motd, only sysadmins
2006/7/11 [Computer/SW/Compilers] UID:43629 Activity:nil
7/11    Is there a way to turn off specific warnings on the intel 9.0 C++
        compilers?  The man page says -wd[warning number] should suppress
        the warning, but that isn't working for me at all.  The only
        think that does is just -w, but that suppresses ALL warnings.
        \_ grep -v warning-that-I-dont-care ...
2006/5/17-22 [Computer/SW/Compilers] UID:43081 Activity:nil
5/16    Hey boys and girls! Do you have time? Do you want to be productive?
        Do you want to be a better person? Then learn something new today,
        like gdb, ddd, strace, nc, gprof, and valgrind! With these new
        skillsets, YOU can make the world a better place!
        \_ So, um, I've monkeyed with all those tools, except nc, what's
           \_ Netcat, likely.  -John
              \- you forgot xargs, mapcar and apply
                 \_ these are really basic, "small steps" skillsets
                    like ls, man, less. -op
                 \_ He didn't ask about tools.   He asked about nc. -John
        \_ Knowing gdb is a lot more important than ddd
2006/3/31-4/1 [Computer/SW/Compilers] UID:42583 Activity:nil
3/31    Does every C++ compiler give totally worthless error messages, or is
        it just gcc?
        \_ Wow, what a great question.  No, not even gcc error messages are
           totally worthless.
           \_ Aww, give the guy a break -- he's probably just having a really
              difficult day.
        \_ We care why?
2006/1/19-21 [Computer/SW/Compilers] UID:41435 Activity:nil
1/19    Political talk is boring, let's talk about the Linux kernel and
        Java compilers! Viva la technology!
        \_ OK:  If I build a reasonably large website using Apache SSIs in
           every page, will I want to shoot myself later?
           And if I enable MultiViews, what could go wrong?
2017/09/20 [General] UID:1000 Activity:popular
Results 151 - 168 of 168   < 1 2 >
Berkeley CSUA MOTD:Computer:SW:Compilers: