c - C语言中EDOM和ERANGE的区别？

Question

errno 从标准库函数中捕获错误信息。但是，有两个宏值 EDOM 和 ERANGE 我觉得很难区分。

来自 cppreference 的示例代码将执行以下操作

#include <stdio.h>
#include <math.h>
#include <errno.h>

void show_errno(void)
{
    const char *err_info = "unknown error";
    switch (errno) {
    case EDOM:
        err_info = "domain error";
        break;
    case EILSEQ:
        err_info = "illegal sequence";
        break;
    case ERANGE:
        err_info = "pole or range error";
        break;
    case 0:
        err_info = "no error";
    }
    fputs(err_info, stdout);
    puts(" occurred");
}

int main(void)
{
    errno = 0;
    acos(+1.1);
    show_errno();
 
    errno = 0;
    log(0.0);
    show_errno();

    return 0;
}

它会产生

domain error occurred
pole or range error occurred

所以我的问题是:哪些操作会导致errno变成EDOM，哪些操作会导致它变成ERANGE？

Answer 1

... what operations will cause errno to become EDOM, and what operations will cause it to become ERANGE?

These are math functions that can be graphed: y = f(x). Invalid values of the independent variable x will produce "domain" errors. Invalid values of the dependent variable y will produce "range" errors. @Fe2O3

或

EDOM means the mathematical function is not defined there, and ERANGE means the computed function cannot give you the mathematical result because it cannot be represented in the result format. @Eric Postpischil

---

EDOM 和 ERANGE 都是在 C 标准中定义的。

For all functions (<math.h>), a domain error occurs if and only if an input argument is outside the domain over which the mathematical function is defined. C17dr § 7.12.1 2

例如ojit_代码

Likewise, a range error occurs if and only if the mathematical result of the function cannot be represented in an object of the specified type, due to extreme magnitude. § 7.12.1 4

例如ojit_代码