| Value | Meaning |
|---|---|
| win321 | Microsoft 32 bit Windows systems |
| win64 | Microsoft 64 bit Windows systems |
| linux | All Linux Systems, except for Android |
| osx | Mac OS X |
| iOS | iOS |
| tvOS | tvOS |
| watchOS | watchOS |
| freeBSD | FreeBSD |
| netBSD | NetBSD |
| openBSD | OpenBSD |
| dragonFlyBSD | DragonFlyBSD |
| solaris | Solaris |
| android | Android |
| otherPosix | Other Posix Systems |
| unknown | Unknown |
Operating system.
Note: This is for cases where you need a value representing the OS at runtime. If you're doing something which should compile differently on different OSes, then please use version (Windows), version (linux), etc.