Hello,

I notice that when pass a non-numeric char to strtod, musl will set errno
to non-zero, but glibc will set errno to zero.
I am curious why this difference exists, and whether it is necessary to
make strtod in musl behave similarly to glibc.

Here is the toy program:


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

int main(int argc, char** argv) {
  errno = 0;
  char input[] = "NA023";
  strtod(input, NULL);
  printf("errno = %d\n", errno);
  perror("strtod");

  return 0;
}

Output (musl):

bash-4.3# ./main
errno = 22
strtod: Invalid argument

Output (glibc, Ubuntu 16.04):
> ./main
errno = 0
strtod: Success



Best,
Xiaowei