The difference between EDOM and ERANGE in C?

Question

errno captures error messages from standard library functions. However, there are two macro values EDOM and ERANGE which I find hard to distinguish.

An example code from cppreference will do the following

#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;
}

and it will produce

domain error occurred
pole or range error occurred

So my question is: what operations will cause errno to become EDOM, and what operations will cause it to become 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

or

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

---

Both EDOM and ERANGE are defined in the C standard.

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

E.g. sqrt(-1)

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

E.g. strtol("1234567890123456789012345678901234567890", 0, 0)