[Ios]clang Diagnostic, Wprotocol.

First, #pragma is essentially a declaration,一般常用的功能就是打注释、尤其是分段注释

但是#pragma 另外一个强大的功能就是处理编译器警告，用的时候可能就没上一个

功能用的那么多，在代码中处理警告却是极其高效的方法。

其中 clang diagnostic 便是#pragma 第一个功能常用的命令，步骤如下

#pragma clang diagnostic push#pragma clang diagnostic ignored "-related commands"    //Your own code #pragma clang diagnostic pop

常见用法

1.方法弃用告警

    #pragma clang diagnostic push            #pragma clang diagnostic ignored "-wdeprecated-declarations"           [TestFlight Setdeviceidentifier:[[uidevice Currentdevice] uniqueidentifier];            #pragma clang diagnostic pop   

2. Incompatible pointer types

    #pragma clang diagnostic push       #pragma clang diagnostic ignored "-wincompatible-pointer-types"       //      #pragma Clang Diagnostic Pop  

3. Circular references

    Completionblock is manually the retain cycle of nilled out and afurlconnectionoperation to break.      #pragma clang diagnostic push      #pragma clang diagnostic ignored "-warc-retain-cycles"          Self.completionblock = ^ { c9/> ...          };      #pragma clang diagnostic pop  

4. No variables used

#pragma clang diagnostic push   #pragma clang diagnostic ignored "-wunused-variable"     int A;   #pragma clang diagnostic pop  




#pargma 用法详情：

http://nshipster.cn/pragma/

http://nshipster.com/clang-diagnostics/


相关的命令列表

http://fuckingclangwarnings.com/

Advanced:

Http://clang.llvm.org/docs/UsersManual.html#diagnostics_pragmas




[Ios]clang Diagnostic, Wprotocol.