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.

Thx

Answer 1

Do it at compile time using #ifdef.

Under windows, WIN32 is defined.

So, do:

#ifdef WIN32
// Windows code here
#else
// UNIX code here
#endif

Answer 2

This is typically done using precompiler directives to control what chunk of code is included/excluded from your build.

#ifdef WIN32
  // ...
#endif

This results in (arguably) uglier code, but targeted binaries.

Answer 3

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

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

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

Answer 4

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.