strtoull linux

unsigned long strtoull(const char *str, char **endptr, int base);

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

int main() {
    const char *str = "12345abc";
    char *endptr;
    unsigned long val = strtoull(str, &endptr, 10);

    if (endptr == str) {
        printf("No digits were found
");
        return 1;
    }

    printf("Converted value: %lu
", val);
    printf("Unconverted part: %s
", endptr);

    return 0;
}

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

int main() {
    const char *str = "12345abc";
    char *endptr;
    errno = 0; // Reset errno before call
    unsigned long val = strtoull(str, &endptr, 10);

    if (endptr == str) {
        printf("No digits were found
");
    } else if (errno == ERANGE) {
        printf("Result out of range
");
    } else {
        printf("Converted value: %lu
", val);
        printf("Unconverted part: %s
", endptr);
    }

    return 0;
}