C语言vs2019对string类型数据报错

Question

//基于C语言的ip地址16进制整型与字符串相转换的简单实现方式
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

unsigned int ipv4_str_to_hex(char* str) {
    char ip1[4] = "";
    char ip2[4] = "";
    char ip3[4] = "";
    char ip4[4] = "";
    char* p = str;
    strcpy(ip1, strsep(&p, "."));
    strcpy(ip2, strsep(&p, "."));
    strcpy(ip3, strsep(&p, "."));
    strcpy(ip4, strsep(&p, "."));
    unsigned int ip = atoi(ip1);
    ip = ip * 256 + atoi(ip2);
    ip = ip * 256 + atoi(ip3);
    ip = ip * 256 + atoi(ip4);
    return ip;
}

void ipv4_hex_to_str(unsigned int iphex, char* ipstr) {
    sprintf(ipstr, "%u.%u.%u.%u", (iphex >> 24) & 0xff, (iphex >> 16) & 0xff, (iphex >> 8) & 0xff);
}

int main() {
    char ipstr[64] = "3131372E37342E3133362E33343B";
    unsigned int a;
    a = ipv4_str_to_hex(ipstr);
    printf("hex ip:0x%08x\n", a);
    char ipstr2[64] = "";
    ipv4_hex_to_str(a, ipstr2);
    printf("str ip is: %s\n", ipstr2);
    return 0;
}

这段代码在vs2019环境下编译报错，提示如下：
错误 LNK2019 无法解析的外部符号 strsep，函数 ipv4_str_to_hex 中引用了该符号 Project1 E:\ota_server_client_0606\Project1\Project1\server_main.obj 1

这是什么原因导致的？

Answer 1

strsep是linux下的，vc没有。
可以用库函数strpbrk写一个