nan

接口定义

C interface：

float nanf(const char *tagp);

double nan(const char *tagp);

参数

返回值

当tagp不为NULL时，返回浮点NAN，如果为NULL，则出现未定义行为，调用者需保证入参不为NULL。

依赖

C: "km.h"

示例

C interface：

// typical usage
const char *a = "0x7ff8000000000000";
const char *b = "0x781";
const char *c = "0x781asdf";
printf("/*\n");
printf(" * nan(%s)=0x%lx\n", a, Asuint64(nan(a)));
printf(" * nan(%s)=0x%lx\n", b, Asuint64(nan(b)));
printf(" * nan(%s)=0x%lx\n", c, Asuint64(nan(c)));
printf(" **/\n");
/*
 * nan(0x7ff8000000000000)=0x7ff8000000000000
 * nan(0x781)=0x7ff8000000000781
 * nan(0x781asdf)=0x7ff8000000000000
 **/