Get the current operating system during runtime in C++
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.
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