Host introspection

Host introspection
You are encouraged to solve this task according to the task description, using any language you may know.

Print the word size and endianness of the host machine.

Ada

<lang ada>with Ada.Text_IO; use Ada.Text_IO; with System; use System;

procedure Host_Introspection is begin

  Put_Line ("Word size" & Integer'Image (Word_Size));
  Put_Line ("Endianness " & Bit_Order'Image (Default_Bit_Order));

end Host_Introspection;</lang> Sample output on a Pentium machine:

Word size 32
Endianness LOW_ORDER_FIRST

ALGOL 68

<lang algol68>INT max abs bit = ABS(BIN 1 SHL 1)-1; INT bits per char = ENTIER (ln(max abs char+1)/ln(max abs bit+1)); INT bits per int = ENTIER (1+ln(max int+1.0)/ln(max abs bit+1));

printf(($"states per bit: "dl$,max abs bit+1)); printf(($"bits per char: "z-dl$,bits per char)); printf(($"bits per int: "z-dl$,bits per int)); printf(($"chars per int: "z-dl$,bits per int OVER bits per char));

printf(($"bits width: "z-dl$, bits width));

STRING abcds = "ABCD"; FILE abcdf; INT abcdi;

INT errno := open(abcdf, "abcd.dat",stand back channel); put(abcdf,abcds); # output alphabetically # reset(abcdf); get bin(abcdf,abcdi); # input in word byte order # STRING int byte order := ""; FOR shift FROM 0 BY bits per char TO bits per int - bits per char DO

 int byte order +:= REPR(abcdi OVER (max abs bit+1) ** shift MOD (max abs char+1))

OD; printf(($"int byte order: "g,", Hex:",16r8dl$,int byte order, BIN abcdi))</lang> Output (Intel i686): <lang algol68>states per bit: 2 bits per char: 8 bits per int: 32 chars per int: 4 bits width: 32 int byte order: ABCD, Hex:44434241</lang> On older CPUs the results would vary:

ALGOL 68R	ALGOL 68RS
~ <lang algol68>bits per char: 6 bits per int: 24 chars per int: 4</lang>	ICL 2900 <lang algol68>bits per char: 8 bits per int: 32 chars per int: 4</lang>	Multics <lang algol68>bits per char: 6 bits per int: 36 chars per int: 6</lang>

C

<lang c>#include <stdio.h>

1. include <stddef.h> /* for size_t */
2. include <limits.h> /* for CHAR_BIT */

int main() {

   int one = 1;
   printf("word size = %d\n", CHAR_BIT * sizeof(size_t)); /* best bet: size_t typically is exactly one word */
   if (*(char *)&one) /* if the least significant bit is located in the lowest-address byte */
       printf("little endian\n");
   else
       printf("big endian\n");
   return 0;

}</lang>

On POSIX-compatible systems, the following also tests the endianness (this makes use of the fact that network order is big endian): <lang c>#include <stdio.h>

1. include <arpa/inet.h>

int main() {

 if (htonl(1) == 1)
   printf("big endian\n");
 else
   printf("little endian\n");

}</lang>

D

<lang d>import std.stdio, std.system;

void main() {

 writefln("word size = ", size_t.sizeof * 8);
 writefln(endian == Endian.LittleEndian ? "little" : "big", " endian");

}</lang>

Erlang

To find the word size: <lang erlang>1> erlang:system_info(wordsize). 4</lang>

In the case of endianness, Erlang's bit syntax by default has a 'native' option which lets you use what is supported natively. As such, there is no function to find endianness. However, one could write one by using bit syntax, setting endianness and then comparing to the native format:

<lang erlang>1> <<1:4/native-unit:8>>. <<1,0,0,0>> 2> <<1:4/big-unit:8>> <<0,0,0,1>> 3> <<1:4/little-unit:8>>. <<1,0,0,0>></lang>

And so the following function would output endiannes:

<lang erlang>endianness() when <<1:4/native-unit:8>> =:= <<1:4/big-unit:8>> -> big; endianness() -> little.</lang>

Factor

<lang factor>USING: alien.c-types io layouts ; "Word size: " write cell 8 * . "Endianness: " write little-endian? "little" "big" ? print</lang>

Forth

<lang forth>: endian

 cr 1 cells . ." address units per cell"
 s" ADDRESS-UNIT-BITS" environment? if cr . ." bits per address unit" then
 cr 1 here ! here c@ if ." little" else ." big" then ."  endian" ;</lang>

This relies on c@ being a byte fetch (4 chars = 1 cells). Although it is on most architectures, ANS Forth only guarantees that 1 chars <= 1 cells. Some Forths like OpenFirmware have explicitly sized fetches, like b@.

Fortran

Works with: Fortran version 90 and later

<lang fortran>INTEGER, PARAMETER :: i8 = SELECTED_INT_KIND(2) INTEGER, PARAMETER :: i16 = SELECTED_INT_KIND(4) INTEGER(i8) :: a(2) INTEGER(i16) :: b

WRITE(*,*) bit_size(1)  ! number of bits in the default integer type

                          ! which may (or may not!) equal the word size

b = Z'1234'  ! Hexadecimal assignment a = (TRANSFER(b, a))  ! Split a 16 bit number into two 8 bit numbers

IF (a(1) == Z'12') THEN  ! where did the most significant 8 bits end up

 WRITE(*,*) "Big Endian"

ELSE

 WRITE(*,*) "Little Endian"

END IF</lang>

F#

A lot of research before I finally came up with an answer to this that isn't dependent on the machine it was compiled on. Works on Win32 machines only (obviously, due to the interop). I think that strictly speaking, I should be double checking the OS version before making the call to wow64Process, but I'm not worrying about it. <lang fsharp>open System open System.Runtime.InteropServices open System.Diagnostics

[<DllImport("kernel32.dll", SetLastError = true, CallingConvention = CallingConvention.Winapi)>] extern bool IsWow64Process(nativeint hProcess, bool &wow64Process);

let answerHostInfo =

   let Is64Bit() =
       let mutable f64Bit = false;
       IsWow64Process(Process.GetCurrentProcess().Handle, &f64Bit) |> ignore
       f64Bit
   let IsLittleEndian() = BitConverter.IsLittleEndian
   (IsLittleEndian(), Is64Bit())</lang>

Haskell

<lang haskell>import Data.Bits import ADNS.Endian -- http://hackage.haskell.org/package/hsdns

main = do

 putStrLn $ "Word size: " ++ bitsize
 putStrLn $ "Endianness: " ++ show endian
     where
       bitsize = show $ bitSize (undefined :: Int)</lang>

J

Method A:

<lang j> ":&> (|: 32 64 ;"0 big`little) {"_1~ 2 2 #: 16b_e0 + a. i. 0 { 3!:1 '' 32 little</lang>

Method B:

<lang j> ((4*#) ,:&": little`big {::~ '7'={.) {: 3!:3 ] 33 b.~_1 32 little</lang>

Java

<lang java>System.out.println("word size: "+System.getProperty("sun.arch.data.model")); System.out.println("endianness: "+System.getProperty("sun.cpu.endian"));</lang>

Modula-3

<lang modula3>MODULE Host EXPORTS Main;

IMPORT IO, Fmt, Word, Swap;

BEGIN

 IO.Put("Word Size: " & Fmt.Int(Word.Size) & "\n");
 IF Swap.endian = Swap.Endian.Big THEN
   IO.Put("Endianness: Big\n");
 ELSE
   IO.Put("Endianness: Little\n");
 END;

END Host.</lang>

Output (on an x86):

Word Size: 32
Endianness: Little

Objective-C

This example is incorrect. It does not accomplish the given task. Please fix the code and remove this message.

<lang objc>NSLog(@"operating system name: %@", [[NSProcessInfo processInfo] operatingSystemName]); NSLog(@"operating system version: %@", [[NSProcessInfo processInfo] operatingSystemVersionString]); //Mac OS X 10.5+: NSLog(@"number of bytes of physical memory: %llu", [[NSProcessInfo processInfo] physicalMemory]); NSLog(@"number of processors: %u", [[NSProcessInfo processInfo] processorCount]);</lang>

Dunno about word size and endianness.

OCaml

This example is incomplete. Please ensure that it meets all task requirements and remove this message.

<lang ocaml>Printf.printf "%d\n" Sys.word_size; (* Print word size *) Printf.printf "%s\n" Sys.os_type; (* Print operating system *)</lang>

Endianness is hidden in ocaml, but there are tricks. For example in Linux or Unix variants, one may use the uname shell command :

<lang ocaml>let uname arg = let name = Filename.temp_file "ocaml_uname" "" in ignore (Sys.command ("uname -" ^ arg ^ " > " ^ name)); let f = open_in name in let s = input_line f in close_in f; Sys.remove name; s;;

1. uname "sm";;

- : string = "Linux i686"</lang>

In most cases, endianness can be infered from informations given by uname.

One may also read files in the /proc directory in order to get informations about the host :

<lang ocaml>(* Reading all the lines from a file. If the loop is implemented by a recursive auxiliary function, the try...with breaks tail recursion if not written carefully *) let lines name = let f = open_in name and r = ref [ ] in (try while true do r := (input_line f)::!r done with End_of_file -> close_in f); List.rev !r

1. lines "/proc/meminfo";;

- : string list = ["MemTotal: 2075240 kB"; "MemFree: 469964 kB";

"Buffers:         34512 kB"; "Cached:        1296380 kB";
"SwapCached:         96 kB"; "Active:         317484 kB";
"Inactive:      1233500 kB"; "HighTotal:     1178432 kB";
"HighFree:        45508 kB"; "LowTotal:       896808 kB";
"LowFree:        424456 kB"; "SwapTotal:     2650684 kB";
"SwapFree:      2650588 kB"; "Dirty:             228 kB";
"Writeback:           0 kB"; "AnonPages:      220036 kB";
"Mapped:          67160 kB"; "Slab:            41540 kB";
"SReclaimable:    34872 kB"; "SUnreclaim:       6668 kB";
"PageTables:       1880 kB"; "NFS_Unstable:        0 kB";
"Bounce:              0 kB"; "WritebackTmp:        0 kB";
"CommitLimit:   3688304 kB"; "Committed_AS:   549912 kB";
"VmallocTotal:   114680 kB"; "VmallocUsed:      5172 kB";
"VmallocChunk:   109320 kB"; "HugePages_Total:     0";
"HugePages_Free:      0"; "HugePages_Rsvd:      0";
"HugePages_Surp:      0"; "Hugepagesize:     4096 kB"]</lang>

PicoLisp

We inspect the ELF header of the executable file (the 'cmd' function returns the path to the command that invoked the interpreter). Note that this (like most other contributions to this task) only tells how the binary was compiled/assembled/linked, not necessarily the nature of the underlying system. <lang PicoLisp>(in (cmd) # Inspect ELF header

  (rd 4)                              # Skip "7F" and 'E', 'L' and 'F'
  (prinl
     (case (rd 1)                     # Get EI_CLASS byte
        (1 "32 bits")
        (2 "64 bits")
        (T "Bad EI_CLASS") ) )
  (prinl
     (case (rd 1)                     # Get EI_DATA byte
        (1 "Little endian")
        (2 "Big endian")
        (T "Bad EI_DATA") ) ) )</lang>

Output:

64 bits
Little endian

PowerShell

<lang powershell>Write-Host Word Size: ((Get-WMIObject Win32_Processor).DataWidth) Write-Host -NoNewLine "Endianness: " if ([BitConverter]::IsLittleEndian) {

   Write-Host Little-Endian

} else {

   Write-Host Big-Endian

}</lang> Note that endianness is essentially a moot point with PowerShell, as there is only a Windows implementation currently and current Windows versions don't run on big-endian systems. But in theory this check should work.

Python

<lang python>>>> import sys, math >>> int(round(math.log(sys.maxint,2)+1)) # this only works in Python 2.x 32 >>> import struct >>> struct.calcsize('i') * 8 32 >>> sys.byteorder little >>> import socket >>> socket.gethostname() 'PADDY3118-RESTING' >>></lang>

R

Word size <lang R>8 * .Machine$sizeof.long # e.g. 32

1. or

object.size(0L) # e.g. 32 bytes</lang> Endianness <lang R>.Platform$endian # e.g. "little"</lang>

Ruby

<lang ruby>word_size = 42.size * 8

byte = [1].pack('i')[0] byte = byte.ord if RUBY_VERSION >= "1.9" byte_order = (byte == 0 ? 'big' : 'little') + ' endian'</lang>

Scheme

Works with: Chicken Scheme

<lang scheme>(define host-info

 (begin
   (display "Endianness: ")
   (display (machine-byte-order))
   (newline)
   (display "Word Size: ")
   (display (if (fixnum? (expt 2 33)) 64 32))
   (newline)))</lang>

Output:

Endianness: little-endian
Word Size: 32

Slate

<lang slate>inform: 'Endianness: ' ; Platform current endianness. inform: 'Word Size: ' ; (Platform current bytesPerWord * 8) printString.</lang> Output:

Endianness: LittleEndian
Word Size: 32

Tcl

This is very straightforward in Tcl. The global array tcl_platform contains these values. In an interactive tclsh: <lang tcl>% parray tcl_platform tcl_platform(byteOrder) = littleEndian tcl_platform(machine) = intel tcl_platform(os) = Windows NT tcl_platform(osVersion) = 5.1 tcl_platform(platform) = windows tcl_platform(pointerSize) = 4 tcl_platform(threaded) = 1 tcl_platform(user) = glennj tcl_platform(wordSize) = 4</lang>

TI-89 BASIC

<lang ti89b>Disp "32-bit big-endian"</lang>