如何正确地格式化atoi函数？

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

int safe_atoi(const char* str) {
    if (str == NULL || *str == '\0') {
        return 0;
    }

    char* endptr;
    long result = strtol(str, &endptr, 10);

    if (*endptr != '\0') {
        // 处理非数字字符的情况
        printf("Invalid input: %s\n", str);
        return 0;
    }

    if (result > INT_MAX || result < INT_MIN) {
        // 处理整数溢出的情况
        printf("Integer overflow: %s\n", str);
        return 0;
    }

    return (int)result;
}

int main() {
    char str1[] = "12345";
    char str2[] = "  -678";
    char str3[] = "12a34";

    int num1 = safe_atoi(str1);
    int num2 = safe_atoi(str2);
    int num3 = safe_atoi(str3);

    printf("num1: %d\n", num1);
    printf("num2: %d\n", num2);
    printf("num3: %d\n", num3);

    return 0;
}