C # Preprocessor Directives #define/#undefine/#if/#elif/#else/#endif

Preprocessor commands are very powerful and are used extensively during programming, such as easy to use in version release, 1, #define (tells the compiler that there is a symbol for the given name) #undefine (delete symbol) 2, #if#elif#else#endif#define本身没有什么作用, typically used in conjunction with other preprocessor directives (#if)

1. Use # define to tell the compiler that a given symbol exists
2. Add a name symbol to VS
3. Use in Unity

 ----Use # define to tell the compiler that a given symbol exists--------------------------------------#define ANDROID #define IOS #define WP using System; using System.Collections.Generic; using system.linq; using system.text; using System.Threading.Tasks; namespace cshapeb { class Test     {#if ANDROID #if QD1 #elif QD2 #elif QD3 #endif #elif IOS #if QD1 #elif QD2 #elif QD3 #endif #elif WP #elif ELSE #else#endif    }}-----add a name symbol to VS--------------------------------------1,debug--> Configuration Manager.
2,debug-->< new ...>.
3, fill in the name Android_debug, and complete the setup, then we can see in DEBUGit's android_debug.

4, configure Android_debug, write the given name symbol in the conditional compilation symbol number, and save.
5, using, we are in the debug mode of words ourAndroid is not enabled, but we switch tounder the Android_debug.The code under the Android symbol is enabled.


-----Use in Unity--------------------------------------buildsetting->playersettings->scripting Define Symbols
-----Unity Pre-defined macros--------------------------------------Platform definition

Unity_editor	Editor calls.
Unity_standalone_osx	Specifically for the definition of Mac OS (including Universal, PPC, and Intelarchitectures) platforms.
Unity_dashboard_widget	Mac OS Dashboard widget (Mac OS Dashboard widget).
Unity_standalone_win	Windows.
Unity_standalone_linux	A standalone application for Linux.
Unity_standalone	Standalone platform (mac,windows or Linux).
Unity_webplayer	Web player (including Windows and Mac Web Player executables).
Unity_wii	Wii console platform.
Unity_iphone	iphone platform.
Unity_android	Android platform.
Unity_ps3	PlayStation 3.
unity_xbox360	Xbox 360.
Unity_nacl	Google Native Client (use this must additionally use Unity_webplayer).
Unity_flash	Adobe Flash.

You can also judge the Unity version, the currently supported version

Unity_2_6	The platform is defined as the major version of Unity 2.6.
Unity_2_6_1	Platform-defined version 1 of the major version 2.6.
Unity_3_0	The platform is defined as the major version of Unity 3.0.
Unity_3_0_0	The platform defines a specific version of Unity 3.0 0.
Unity_3_1	The platform is defined as the major version of Unity 3.1.
Unity_3_2	The platform is defined as the major version of Unity 3.2.
Unity_3_3	The platform is defined as the major version of Unity 3.3.
Unity_3_4	The platform is defined as the major version of Unity 3.4.
Unity_3_5	The platform is defined as the major version of Unity 3.5.
Unity_4_0	The platform is defined as the major version of Unity 4.0.
Unity_4_0_1	Major Version 4.0.1 a unified platform definition.
Unity_4_1	The platform is defined as the major version of Unity 4.1.

From for notes (Wiz)

C # Preprocessor Directives #define/#undefine/#if/#elif/#else/#endif