isfinite可以在Linux、BSD和Windows上编译，但不能在SmartOS上编译

Question

我正在尝试将Quadlods移植到SmartOS。它在Linux和DragonFly BSD上编译和运行。我没有尝试过在Windows上运行它，但是其他使用xy类和isfinite方法的程序在Windows上编译和运行。然而，在SmartOS上编译它时，我得到了这个错误：

[ 15%] Building CXX object CMakeFiles/quadlods.dir/filltest.cpp.o
In file included from /usr/include/math.h:36,
                 from /opt/local/gcc9/include/c++/9.3.0/bits/std_abs.h:40,
                 from /opt/local/gcc9/include/c++/9.3.0/cstdlib:77,
                 from /opt/local/gcc9/include/c++/9.3.0/ext/string_conversions.h:41,
                 from /opt/local/gcc9/include/c++/9.3.0/bits/basic_string.h:6493,
                 from /opt/local/gcc9/include/c++/9.3.0/string:55,
                 from /opt/local/gcc9/include/c++/9.3.0/stdexcept:39,
                 from /opt/local/gcc9/include/c++/9.3.0/optional:38,
                 from /opt/local/gcc9/include/c++/9.3.0/bits/node_handle.h:39,
                 from /opt/local/gcc9/include/c++/9.3.0/bits/stl_tree.h:72,
                 from /opt/local/gcc9/include/c++/9.3.0/map:60,
                 from /home/phma/src/quadlods/quadlods.h:27,
                 from /home/phma/src/quadlods/filltest.h:25,
                 from /home/phma/src/quadlods/filltest.cpp:26:
/home/phma/src/quadlods/xy.h:35:8: error: expected ')' before '!=' token
   35 |   bool isfinite() const;
      |        ^~~~~~~~

定义宏的文件是/usr/include/iso/math_c99.h，它会导致这个奇怪的错误：

#define isfinite(x) (__builtin_isfinite(x) != 0)

头文件中的类定义是

class xy
{
public:
  xy(double e,double n);
  xy();
  double getx() const;
  double gety() const;
  double length() const;
  bool isfinite() const;
  bool isnan() const;
  friend xy operator+(const xy &l,const xy &r);
  friend xy operator+=(xy &l,const xy &r);
  friend xy operator-=(xy &l,const xy &r);
  friend xy operator-(const xy &l,const xy &r);
  friend xy operator-(const xy &r);
  friend xy operator*(const xy &l,double r);
  friend xy operator*(double l,const xy &r);
  friend xy operator/(const xy &l,double r);
  friend xy operator/=(xy &l,double r);
  friend bool operator!=(const xy &l,const xy &r);
  friend bool operator==(const xy &l,const xy &r);
  friend xy turn90(xy a);
  friend xy turn(xy a,int angle);
  friend double dist(xy a,xy b);
protected:
  double x,y;
};

有没有可能在不重命名该方法的情况下在SmartOS上进行编译？我想取消定义isfined宏，但是在另一个程序中(不是Quadlods，它的头文件只有Quadlos.h)，xy类在库的头文件中。此外，isfinite方法调用std::isfinite。

Answer 1

Jonathan Perkin在IRC上给我的解决方案是将#include <cmath>放在xy.h的include guard之后。这取消了宏的定义。它现在可以在Linux、BSD和SmartOS上编译。