Beefy Boxes and Bandwidth Generously Provided by pair Networks
Don't ask to ask, just ask
 
PerlMonks  

I need to know if 32-bit or 64-bit perl is running my script.

by Anonymous Monk
on Sep 14, 2013 at 04:31 UTC ( #1054052=perlquestion: print w/ replies, xml ) Need Help??
Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

32-bit solaris used to have process start time at position 264 in psinfo. 64-bit has it at 332 (I'm sort of guessing on that.) How can I tell if my perl process is running under a 32-bit binary, or 64-bits?

(Bonus points for AIX.)

Comment on I need to know if 32-bit or 64-bit perl is running my script.
Re: I need to know if 32-bit or 64-bit perl is running my script.
by mbethke (Hermit) on Sep 14, 2013 at 05:47 UTC
    That's nasty, I hope you're writing something that will abstract this away for others :) In C you could check if 0 == 1L<<32 but that would effectively identify your userland which IIRC doesn't have to match the kernel on Solaris. In Perl, even an interpreter running in 32bit userland can use 64bit ints so not even that works. I suppose the most reliable way would be to parse uname -a output somehow.
Re: I need to know if 32-bit or 64-bit perl is running my script.
by BrowserUk (Pope) on Sep 14, 2013 at 05:58 UTC

    Should work anywhere:

    C:\test>\perl64\bin\perl -e"print length pack 'P', -1" 8 C:\test>\perl32\bin\perl -e"print length pack 'P', -1" 4

    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
      To see the userland code size that's a nice way. But if the kernel determines where stuff is placed in a struct and the kernel can run both 32- and 64-bit executables, you're still fuct. Plus some weird architectures like AS/400 (relevant for AIX) use 128bit pointers even on 32bit ALUs.
        But if the kernel determines where stuff is placed in a struct and the kernel can run both 32- and 64-bit executables, you're still fuct.

        That is certainly not the case for Intel processors. Even running under 64-bit kernels; 32-bit processes only use 32-bit pointers.

        Plus some weird architectures like AS/400 (relevant for AIX) use 128bit pointers even on 32bit ALUs.

        I know naff all about AS/400, but since the original AS/400 hardware was 48-bit; and it has all been 64-bit for the last decade or so; one wonders whether the question is even relevant for such hardware?


        With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
        Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
        "Science is about questioning the status quo. Questioning authority".
        In the absence of evidence, opinion is indistinguishable from prejudice.
Re: I need to know if 32-bit or 64-bit perl is running my script.
by dave_the_m (Parson) on Sep 14, 2013 at 08:16 UTC
    If you want the perl process's start time, then that's already available in $^T. If you want a different prcocess's start time, then the 32/64-bitness of the executing perl should be irrelevant (a system may be running a mixture of 32-bit and 64-bit executables). Unless the psinfo offset is determined not by the individual processes, but by the type of the kernel. If the latter, then its a while since I've used solaris, but IIRC, psrinfo(1) gives you that info.

    Dave.

Re: I need to know if 32-bit or 64-bit perl is running my script.
by flexvault (Parson) on Sep 14, 2013 at 09:49 UTC

    AM,

    I may be missing your point, but if you want to see if it's 32/64 bit Perl on AIX, try this:

    [path/]perl -V | grep 32 # or 64
    and you will get something like this:
    . . . -maix32 # or 64
    This gives you the C compiler info for the Perl executable.

    Regards...Ed

    "Well done is better than well said." - Benjamin Franklin

      Why use external commands when everything and more is already available?

      $ perl -V:ptrsize ptrsize='8'; $ perl -MConfig -wE'say $Config{ptrsize}' 8 $ perl -MData::Peek -MConfig::Perl::V -we'DDumper (Config::Perl::V::my +config ()->{config})'

      Enjoy, Have FUN! H.Merijn

        Tux,

        Very Nice!

        but... something to keep in mind:

        • You may not be able in install CPAN modules in a production system.

        I tested the performance on a test system:

        # *Your method* after installing 2 CPAN modules real 0m0.84s user 0m0.76s sys 0m0.008s # *My method* calling Perl from the command line real 0m0.028s user 0m0.032s # Note: I did this 3 times and 'user' > 'real' +was every time??? sys 0m0.004s

        Granted your routines providing a lot of information, but doing a 'system' call to get some specific information may not be that bad of a hit.

        I'm still going to add this to my bag of tricks. Good job!

        Regards...Ed

        "Well done is better than well said." - Benjamin Franklin

Re: I need to know if 32-bit or 64-bit perl is running my script.
by Anonymous Monk on Sep 14, 2013 at 18:16 UTC

    Thanks for all of your help. $^T is especially exciting.

    You've all stimulated the more general question, though: can the root user look at any random process's info and determine if it is running in 32 or 64 bit mode?

    I like to think that something under the proc tree should tell me.

      I meant /proc, not proc tree.

Re: I need to know if 32-bit or 64-bit perl is running my script.
by Perlbotics (Abbot) on Sep 15, 2013 at 12:22 UTC

    When in Solarisland, ask Solaris (pflags).

    This one is ultra-fragile, but decide yourself if you can use or expand it!

    use strict; use warnings; #-- returns 32 or 64, or 0 in case of error # optional argument: PID of another process; defaults to current PID # see also: http://docs.oracle.com/cd/E26502_01/html/E29030/pflags-1 +.html (pflags) # http://docs.oracle.com/cd/E26502_01/html/E28556/proc-pro +vider.html (psinfo_t section) # "...The pr_dmodel field is set to either PR_MODEL_ILP32, denoting +a 32bit process, # or PR_MODEL_LP64, denoting a 64bit process." # # WARNING! Tested under Solaris 10/11 only! # sub solaris_bits { my $pid = shift || $$; my $pflags = qx{LANG=C /usr/bin/pflags $pid 2>&1}; #-- "data model" should be '_ILP32' or '_LP64' return $pflags =~ /data model\s*=\s*\D*(\d+)/ms ? $1 : 0; } print "Bits (init): ", solaris_bits(1) || 'n/a' , "\n"; # PID==1 (need +s privileges!) print "Bits (self): ", solaris_bits() || 'n/a' , "\n"; # PID==$$

    However, when checking bit-width for the current perl process ($pid == $$), I would rather use BrowserUks pack() approach.
    There is also Solaris::Procfs but the bug-reports indicate, that it doesn't compile in a 64-bit environment. Nice opportunity to make this module work again (wink).

Re: I need to know if 32-bit or 64-bit perl is running my script.
by Tux (Monsignor) on Sep 16, 2013 at 06:44 UTC
Re: I need to know if 32-bit or 64-bit perl is running my script.
by DrHyde (Prior) on Sep 16, 2013 at 10:36 UTC
    I do something like this:

    $ perl -e 'eval { my @foo;$foo[2**32]="1" } || warn("Not big enough\n" +)'

    That will warn with a 32-bit perl. However, the pointer size of an executable binary (and the libs it's linked against) doesn't necessarily tell you whether the OS is 32- or 64-bit. On many OSes (not sure about Solaris) a 32-bit binary can run on 32- or 64-bit OSes. Also beware that a perl with 32-bit pointers on a 32-bit OS can still, if compiled with the right options, have 64 bit integers and access large files.

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: perlquestion [id://1054052]
Approved by kcott
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others wandering the Monastery: (2)
As of 2014-09-20 15:22 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?

    How do you remember the number of days in each month?











    Results (160 votes), past polls