Arduino的：错误：“ABS”在此范围中未声明 [英] Arduino: error: 'abs' was not declared in this scope

问题描述

我工作的一个Arduino库需要的ABS（）函数：

I'm working on an arduino library needing the abs() function:

#include <math.h>
normTransFreq1 = abs(1.0);

错误：ABS在此范围中未声明

Error: 'abs' was not declared in this scope

由于文件math.h 已经包含在CPP，我完全不知道该如何解决这个问题。一个新的Arduino 1.5.2的安装并没有帮助。

As math.h is already included in the cpp I'm entirely unsure how to fix this problem. A new install of arduino 1.5.2 didn't help.

推荐答案

刚刚找到了解决办法：

无需为库包含math.h中。相反，应该Arduino.h加入以下的头文件中包括：

Including math.h is not needed for the library. Instead, Arduino.h should be included by adding the following to the header file:

#if ARDUINO >= 100
  #include "Arduino.h"
#else
  #include "WProgram.h"
#endif

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