Detect MS Windows

Question

Challenge

Create a program that returns a truthy value when run on Microsoft Windows (for simplicity we'll stick with Windows 7, 8.1 and 10) and a falsey value when run on any other operating system (OSX, FreeBSD, Linux).

Rules

• Code that fails to run/compile on a platform doesn't count as a falsey value.

Winning criteria

I'm labelling this as code-golf, so lowest score wins, but I'm also very interested in seeing creative solutions to this problem.

Answer 1

Powershell 6, 10 bytes

$isWindows

Powershell 6 intoduce 3 predefined variables: $isWindows, $isLinux and $IsMacOs.

Answer 2

FPC, 61 chars

begin{$ifdef win32}write('f');{$else}write('nf');{$endif}end;

Answer 3

Lua, 21 Bytes

os.execute"dir c:\\"

It will error if not on windows and list the C:\ directory if on windows.

Answer 4

IBM/Lotus Notes Formula Language, 22 21 bytes

@Like(@Platform;"W%")

Previous versions:

@Left(@Platform;1)="W"

or

@Begins(@Platform;"W")

Computed field formula on a Notes form. @Platform returns 1 of:

AIX/64
Linux/64
Macintosh
OS/400®
UNIX
Windows/32
Windows/64

So the formula returns 1 (@True) if the platform starts with "W" and 0 (@False) if not.

Answer 5

LibreOffice Calc / OpenOffice Calc, 21 bytes

Code:

=INFO("system")="WNT"

Microsoft Excel, 23 bytes

Code:

=INFO("system")="pcdos"

Result:

Returns TRUE if Windows; FALSE otherwise.

Answer 6

tcl, 51

puts [string match windows $tcl_platform(platform)]

I don't have a Windows machine online, but on http://rextester.com/live/OVTY1488 replace windows by unix to see it output 1 instead of 0.

2nd attempt:

tcl, 40

puts [string match W* $tcl_platform(os)]

assuming Windows is the only system the name begins on a W.

3rd attempt:

tcl, 26

puts [info exists env(OS)]

assuming Windows is the only system the OS environment variable is defined.

Answer 7

Ruby, 38 bytes

Stealing the code from here:

exit (RUBY_PLATFORM=~/(?<!r)win/)!=nil

Return 0 on OK, to keep with shell conventions. We need the funny (?<!r) negative look-behind to avoid matching darwin, although if Microsoft device to make a vrwin Windows version for virtual reality the code will fail... On JRuby, though, this doesn't work so well, so instead:

Ruby including JRuby, 52 bytes

exit (RbConfig::CONFIG['host_os']=~/(?<!r)win/)!=nil

I don't have raw Windows, just Cygwin, but if the host_os is windows then we need to distinguish nil and 0.

Ruby plus gem install os, 25 (+9?)

This needs an extra gem, so we might have to add an extra 9 bytes for gem i os at the command line:

require 'os'
exit OS.windows?

This also avoids the darwin problem completely!

Answer 8

PHP, 18 bytes

<?=!(PHP_EOL^'=');

Explanation

PHP_EOL, as its name might suggest, returns the line separator on a given system. On Windows, this is CRLF, and on other platforms, this is LF.

^ is binary XOR. '=' XOR "\r" is '0', and PHP's string bitwise operations truncate to the length of the shortest string, so "\r\n" XOR '=' is also '0'.

! is boolean NOT. In PHP, "0" is considered falsy. So, when we're on Windows, PHP will negate this to true. When we're not on Windows, we get a truthy value ('7') which PHP negates to false.

<?= is the short opening tag for echo.

Answer 9

Ruby 2, 17 14 bytes

17 byte solution: Gem.win_platform? This only works on the newer versions of ruby, as in the older versions you would have to require rubygems.

---

14 byte solution:

system 'del a' This command outputs true if on windows, because there is a command called del in Windows, but outputs nil (falsey) on Linux and Mac because there is no such command as del in Unix. Oh, and if you are on windows it will delete a file called a in your current directory, that's an unintended side effect :P

Answer 10

Python 3, 29 bytes

import os;exit(os.name!='nt')

Probably should have tryed that first....

Previous answer (41 bytes)

Two answers I found that are the same size

import os;exit(-hasattr(os,"P_DETACH")+1)

and

import sys;exit(-hasattr(sys,"winver")+1)

also -+1 is a neat way to negate the output, gonna keep that one noted

Answer 11

C (gcc), x64 only, 37 bytes

asm("m:_m:.int 50066");f(){m(2,1,0);}

Try it online!

Function called f(). Returns 1 for Windows, 0 for non-Windows.

You wanted a "creative solution"? Here you go. Unfortunately, it isn't as short or portable as the other C solution. (TODO: x86, ARM, and ARM64 polyglot /s)

Expanded:

// ASM
// We need both m and _m because macOS uses leading underscores for
// C symbols, while Windows and Linux do not.
m:
_m:
        // We manually encode these in the golfed code to save space.
        // eax = edx
        xchg    eax, edx // 0x92
        ret              // 0xC3
// C
int m(int, int, int);
int f()
{
    // The first parameter can be anything, I use 2 for ease of explanation.
    return m(2, 1, 0);
}

What does it do? It uses the fact that Windows and Linux (and Mac, BSD, etc) use different calling conventions on x64.

So, when GCC tries to call m(2, 1, 0), on Windows it will use the Microsoft x64 calling convention (rcx, rdx, r8, r9):

    mov     ecx, 2
    mov     edx, 1
    mov     r8d, 0
    call    m

However, on Linux, Mac, BSD, etc, it will use the System V calling convention (rdi, rsi, rdx, rcx, r8, r9):

    mov     edi, 2
    mov     esi, 1
    mov     edx, 0
    call    m

As I have bolded, edx is used on both platforms, but since they represent different parameters in the calling conventions, Windows and non-Windows will get different values.

With some inline assembly, we can get GCC to return the value of edx instead of the third parameter.

To test how it would function on Windows, simply uncomment the prototype at the top, which uses an attribute to force GCC to use the Microsoft ABI.

Answer 12

Elixir, 19 bytes

{:win32,_}=:os.type

Exit code 0 for Windows, 1 for others.

Answer 13

Scala, 71 bytes

object W extends App{print(sys.env.get("OS").get.contains("Windows"))}

Answer 14

Dartlang, 43 bytes

import'dart:io';main()=>Platform.isWindows;

First answer one here, so I hope this is okay :)

Answer 15

D, 43 bytes

int f(){version(Windows)return 0;return 1;}

D ... is horrible at golfing. But it does have a version construct, so I thought I'd post an answer in D.

And ... there's really no point in putting a TIO link, since TIO is ran on only one type of OS.

Answer 16

SQL 2017, 61 bytes

SELECT IIF(host_platform='Linux',0,1)FROM sys.dm_os_host_info

SQL 2017 is the first MS SQL version that can run on a platform other than Windows. The system view sys.dm_os_host_info returns either Linux or Windows, so (at least in this version) anything that isn't on Linux is on Windows.

Answer 17

Rust, 14 bytes

||!cfg!(unix);

The target_family attribute is windows on Windows and (most) others have unix.

Answer 18

Julia 0.6, 8 bytes

!is_unix

Try it online!

Julia 1.0, 11 bytes

!Sys.isunix

Try it online!

Answer 19

Factor, 11 bytes

os windows?

Try it online!

Answer 20

Nim, 20 bytes

echo defined windows

Try it online!

Answer 21

05AB1E, 26 19 bytes

'ª¬7£’ÿ :ï´.ƒª’.E2å

Try it online!

'ª¬7£’...’.E2å  # trimmed program
             å  # is...
            2   # literal...
             å  # in...
          .E    # result of running...
     ’...’      # "ÿ :os.type"...
                # (implicit) with ÿ replaced by...
    £           # first...
   7            # literal...
    £           # characters of...
'ª¬             # "inspection"...
          .E    # as Elixir code...
             å  # ?
                # implicit output

=================================================

inspect :os.type  # full program
        :os.type  # return tuple of OS family and OS name...
inspect           # as a string

:os.type return values:

Family	Names
unix	A result from running uname -s. No Unix kernels have 2 in their name, so if the machine is running Unix, the program will return 0.
win32	nt or windows

05AB1E (legacy), 21 bytes

’__£Ø__('ï´').ˆ³’.EÇÈ

Try it online!

’...’.EÇÈ  # trimmed program
        È  # push 1 minus...
       Ç   # codepoint of...
     .E    # result of running...
’...’      # "__import__('os').sep"...
     .E    # as python code...
        È  # modulo 2
           # implicit output

=================================================

__import__('os').sep  # full program
__import__(    )      # return...
           'os'       # operating system...
                .sep  # file path separator

Answer 22

Lua (LuaJIT), 17 bytes

print(jit.os>"V")

Try it online!

Answer 23

Thunno 2, 28 bytes

‘\_\_Ʋ¡\_\_('Ỵġ').ẓ÷()‘E`ż³=

Uses platform.system(), as suggested in this SO answer.

Explanation

‘...‘E`ż³=  # Full program
‘...‘       # Push compressed string "__import__('platform').system()"
     E      # Evaluate as Python code (returns "Linux"/"Darwin"/"Windows")
      `ż³   # Push compressed string "Windows"
         =  # Are they equal?
            # Implicit output

Answer 24

Racket, 26 17 bytes

Shameless plug for the TCL answer I saw that used the OS environment variable.

(and(getenv"OS"))

---

(Old answer)

Pretty straight forward. system-type with no argument returns a symbol indicating the system operating system type.

(eq?'windows(system-type))

Answer 25

Nim, 37 bytes

quit when defined(windows): 0 else: 1

Returns exit code 0 for Windows, 1 for all other operating systems. Uses conditional compilation with when.

Answer 26

PowerShell, 17

gdr|? P* -like *y

Abusing the fact that there's no Registry PSProvider on non-Windows systems.

Answer 27

Node.js, 23 bytes

_=>os.platform=="win32"

Answer 28

Python 3, 78 bytes

Raises a KeyError exception if it can't determine if running on Windows. On not-Windows it can return either None or 0 (both are falsy), on Windows it returns 1.

def f():
 try:open(':','x')
 except Exception as e:return{17:0,22:1}[e.errno]

: is a forbidden character on Windows (also on DOS, etc.)

Answer 29

GNU AWK, 45 37 bytes

BEGIN{print PROCINFO["platform"]~/w/}

Try it online!

Evaluates the PROCINFO["platform"] built-in variable, and returns 1 if it matches any w character; returns 0 otherwise. Why, you ask? According to the GNU AWK manual, only mingw option has a letter w:

PROCINFO["platform"]

    This element gives a string indicating the platform for which
    gawk was compiled. The value will be one of the following:

    "mingw"
        Microsoft Windows, using MinGW.

    "os390"
        OS/390.

    "posix"
        GNU/Linux, Cygwin, Mac OS X, and legacy Unix systems.

    "vms"
        OpenVMS or Vax/VMS.

Answer 30

PowerShell, 18 bytes

$env:OS-like"Win*"

Try it online!