nan.h

来自「Glibc 2.3.2源代码(解压后有100多M)」· C头文件 代码 · 共 6 行

#ifndef _MATH_H
#error "Never use <bits/nan.h> directly; include <math.h> instead."
#endif

/* This file should define `NAN' on machines that have such things.  */