Get the current operating system during runtime in C++

Question

I need to figure out the operating system my program is running on during runtime.

I'm using Qt 4.6.2, MinGW and Eclipse with CDT. My program shall run a command-line QProcess on Windows or Linux. Now I need a kind of switch to run the different code depending on the operating system.

Answer 1

Actually the Operating System is defined by the Q_OS_... macros. Just saying. The Q_WS_... are windowing system. Not exactly the same. (I'm just reading what the author of the question wrote.... "operating system".)

These declarations are found in the qglobal.h file.

Use Q_OS_x with x being one of:

 DARWIN   - Darwin OS (synonym for Q_OS_MAC)
 SYMBIAN  - Symbian
 MSDOS    - MS-DOS and Windows
 OS2      - OS/2
 OS2EMX   - XFree86 on OS/2 (not PM)
 WIN32    - Win32 (Windows 2000/XP/Vista/7 and Windows Server 2003/2008)
 WINCE    - WinCE (Windows CE 5.0)
 CYGWIN   - Cygwin
 SOLARIS  - Sun Solaris
 HPUX     - HP-UX
 ULTRIX   - DEC Ultrix
 LINUX    - Linux
 FREEBSD  - FreeBSD
 NETBSD   - NetBSD
 OPENBSD  - OpenBSD
 BSDI     - BSD/OS
 IRIX     - SGI Irix
 OSF      - HP Tru64 UNIX
 SCO      - SCO OpenServer 5
 UNIXWARE - UnixWare 7, Open UNIX 8
 AIX      - AIX
 HURD     - GNU Hurd
 DGUX     - DG/UX
 RELIANT  - Reliant UNIX
 DYNIX    - DYNIX/ptx
 QNX      - QNX
 QNX6     - QNX RTP 6.1
 LYNX     - LynxOS
 BSD4     - Any BSD 4.4 system
 UNIX     - Any UNIX BSD/SYSV system

The window system definitions are like this:

Use Q_WS_x where x is one of:

 MACX     - Mac OS X
 MAC9     - Mac OS 9
 QWS      - Qt for Embedded Linux
 WIN32    - Windows
 X11      - X Window System
 S60      - Symbian S60
 PM       - unsupported
 WIN16    - unsupported

One of the main problems with using #ifdef is to make sure that if you compile on a "new" platform (never compiled that software on that platform) then you want to use #elif defined(...) and at least an #else + #error ...

#ifdef Q_OS_LINUX
  std::cout << "Linux version";
#elif defined(Q_OS_CYGWIN)
  std::cout << "Cygwin version";
#else
#error "We don't support that version yet..."
#endif

Answer 2

In Qt the following OS macros are defined for compile time options

// pre Qt5 Qt/X11 = Q_WS_X11 is defined.
Qt/Windows = Q_WS_WIN is defined.
Qt/Mac OS X = Q_WS_MACX is defined

// For Qt5 onwards Qt/X11 = Q_OS_X11 is defined.
Qt/Windows = Q_OS_WIN is defined.
Qt/Mac OS X = Q_OS_MACX is defined

Then the QSysInfo class gives you the OS version and other options at runtime.

Answer 3

Qt offers QSysInfo if you really need to get at this at run-time. Useful for appending to a crash report but for anything else try to do it at compile time.

Answer 4

Most of these answers provide solutions for determining the required info at a compile time, when your app is being compiled on your development machine.

Here is a how you get the required info during runtime, when your app is run by users of your app on their machines.

qDebug() << "currentCpuArchitecture():" << QSysInfo::currentCpuArchitecture();
qDebug() << "productType():" << QSysInfo::productType();
qDebug() << "productVersion():" << QSysInfo::productVersion();
qDebug() << "prettyProductName():" << QSysInfo::prettyProductName();

Typical result:

21:43:09.855 Debug: currentCpuArchitecture(): "x86_64"
21:43:09.855 Debug: productType(): "windows"
21:43:09.855 Debug: productVersion(): "10"
21:43:09.855 Debug: prettyProductName(): "Windows 10 (10.0)"

Documentation for QSysInfo is here.

Answer 5

Since Qt5 macroses Q_WS_* are not defined!

You should use Q_OS_* macroses instead:

Q_OS_AIX
Q_OS_ANDROID
Q_OS_BSD4
Q_OS_BSDI
Q_OS_CYGWIN
Q_OS_DARWIN - Darwin-based OS such as OS X and iOS, including any open source version(s) of Darwin.
Q_OS_DGUX
Q_OS_DYNIX
Q_OS_FREEBSD
Q_OS_HPUX
Q_OS_HURD
Q_OS_IOS
Q_OS_IRIX
Q_OS_LINUX
Q_OS_LYNX
Q_OS_MAC - Darwin-based OS distributed by Apple, which currently includes OS X and iOS, but not the open source version.
Q_OS_NETBSD
Q_OS_OPENBSD
Q_OS_OSF
Q_OS_OSX
Q_OS_QNX
Q_OS_RELIANT
Q_OS_SCO
Q_OS_SOLARIS
Q_OS_ULTRIX
Q_OS_UNIX
Q_OS_UNIXWARE
Q_OS_WIN32 - 32-bit and 64-bit versions of Windows (not on Windows CE).
Q_OS_WIN64
Q_OS_WIN - all supported versions of Windows. That is, if Q_OS_WIN32, Q_OS_WIN64 or Q_OS_WINCE is defined.
Q_OS_WINCE
Q_OS_WINPHONE
Q_OS_WINRT

More details in documentation of QtGlobal