ip地址转换htonl的用法

说明

u_long PASCAL FAR htonl ( __in u_long hostlong);

htonl（将32位主机字符顺序转换成网络字符顺序）(用于IP的转换)

IP转换为数值

unsigned long StrIp4ToValue(const char* strIp)
{	//255.255.255.255
	char buf[16] = { 0 };
	strncpy_s(buf, strIp, 16);
	char *next_token1 = NULL;
	char* token = strtok_s(buf, ".", &next_token1);
	long ip[4] = { 0 };
	int i = 0;
	while (token&&i < 4)
	{
		int nValue = atoi(token);
		ip[i] = nValue;
		i++;
		token = strtok_s(NULL, ".", &next_token1);
	}
	unsigned long ipValue = ip[3] + (ip[2] << 8) + (ip[1] << 16) + (ip[0] << 24);
	return ipValue;
}

使用htons，htonl

u_long nHost = StrIpToValue("192.168.8.24")

sockaddr_in mySockaddr = {0};
mySockaddr.sin_family = AF_INET;
mySockaddr.sin_port = htons(nPort);
mySockaddr.sin_addr.S_un.S_addr = htonl(nHost); 

// 等价于
mySockaddr.sin_addr.s_addr = inet_addr("192.168.8.24");