These variables store build and version numbers of the 32-bit Windows operating systems. Declarations for these variables in STDLIB.H are as follows:
externunsignedint_osver;
externunsignedint_winmajor;
externunsignedint_winminor;
externunsignedint_winver;
These variables are useful in programs that run in different versions of Windows NT or Windows 95.
| Variable | Description |
| _osver | Current build number |
| _winmajor | Major version number |
| _winminor | Minor version number |
| _winver | Holds value of _winmajor in high byte and value of _winminor in low byte |