strtoll 溢出时未将 errno 设置为 ERANGE

Question

I'm parsing a long long value using fgets and strtoll as one does, but strtoll is not setting errno to ERANGE when an overflow occurs like it's supposed to.

From the man page :

The strtol() function returns the result of the conversion, unless the value would underflow or overflow. If an underflow occurs, strtol() returns LONG_MIN . If an overflow occurs, strtol() returns LONG_MAX. In both cases, errno is set to ERANGE . Precisely the same holds for strtoll() (with LLONG_MIN and LLONG_MAX instead of LONG_MIN and LONG_MAX) .

Sample code without fgets for MRE purposes:

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

int main(){

    long long number; //max value 9223372036854775807   
    char input[] = "12345678976543245678976543";
    char *end;

    number = strtoll(input, &end, 10);

    printf("%d %d <%s> %lld %lld\n", errno, ERANGE, input, (long long)number, LLONG_MAX);
    //prints 0 for errno and 34 for ERANGE regardless of overflow
    //eerno should be set to ERANGE so it should be 34

    int e = errno; //further testing, assigning errno
    printf("%d", e);// again prints 0 should be 34
}

Output is:

0 34 <12345678976543245678976543> 9223372036854775807 9223372036854775807
0

Should be:

34 34 <12345678976543245678976543> 9223372036854775807 9223372036854775807
34

This is highly confusing to me, especially because in an online compiler it seems to work fine.

I'm using gcc version 9.3.0 (Ubuntu 9.3.0-10ubuntu2), ldd (Ubuntu GLIBC 2.31-0ubuntu9) 2.31 in a recently updated Linux Mint 20.

Answer 1

I reinstalled the entire system and the problem is gone now, I should have maybe reported it, I was thinking about my problems more than in the community.

The likely situation that caused these issues is the fact that I glazed over some of the recommended steps in upgrading my system.

The circumstantial evidence:

• There were other issues like a wifi error, problems with the GRUB and with the timezone, they are also gone after the new instalation.

• I also updgraded my desktop just to see if I could reproduce the same problems, but this time following carefully all the steps and everything works fine.

So for anyone upgrading UNIX systems, pay atention to the upgrade instructions . And have backups, it saved my life in this instance.