凡被定义战俘功能和C实现？ [英] Where is pow function defined and implemented in C?

问题描述

我读了战俘（双，双）功​​能中的文件math.h中定义，但我找不到它的声明。

有谁知道这个功能的声明？并且它用C实现在哪里？

参考：

  

http://publications.gbdirect.co.uk/ C％5Fbook /第九章/数学％5Ffunctions.html

解决方案

很多时候，一个包含文件，如＆LT;文件math.h＆GT; 将包括其他头文件实际上宣告你希望在＆LT看到的功能;文件math.h＆GT; 。我们的想法是，该方案得到什么，它预计，当它包括＆LT;文件math.h方式＆gt; ，即使实际的功能定义在其他一些头文件

找到一个标准库函数的实施的如 POW（）完全是另一回事。你将不得不源$ C ​​$ C挖掘到C标准的运行时库，并找到实现在那里。

I read that the pow(double, double) function is defined in "math.h" but I can't find its declaration.

Does anybody know where this function declared? And where is it implemented in C?

Reference:

http://publications.gbdirect.co.uk/c%5Fbook/chapter9/maths%5Ffunctions.html

解决方案

Quite often, an include file such as <math.h> will include other header files that actually declare the functions you would expect to see in <math.h>. The idea is that the program gets what it expects when it includes <math.h>, even if the actual function definitions are in some other header file.

Finding the implementation of a standard library function such as pow() is quite another matter. You will have to dig up the source code to your C standard runtime library and find the implementation in there.

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