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常见的网络字节转换函数有：
htons()：host to network short，将short类型数据从主机字节序转换为网络字节序。
ntohs()：network to host short，将short类型数据从网络字节序转换为主机字节序。
htonl()：host to network long，将long类型数据从主机字节序转换为网络字节序。
ntohl()：network to host long，将long类型数据从网络字节序转换为主机字节序。

通常，以s为后缀的函数中，s代表2个字节short，因此用于端口号转换；以l为后缀的函数中，l代表4个字节的long，因此用于IP地址转换。
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cat hto.c
#include <stdio.h> #include <stdlib.h> int main(){     unsigned short host_port = 0x1234, net_port;     unsigned long host_addr = 0x12345678, net_addr;     net_port = htons(host_port);     net_addr = htonl(host_addr);     printf("Host ordered port: %#x\n", host_port);     printf("Network ordered port: %#x\n", net_port);     printf("Host ordered address: %#lx\n", host_addr);     printf("Network ordered address: %#lx\n", net_addr);     return 0; }

make hto
cc     hto.c   -o hto

#./hto
Host ordered port: 0x1234
Network ordered port: 0x3412
Host ordered address: 0x12345678
Network ordered address: 0x78563412


cat inetaddr.c
#include <stdio.h> #include <stdlib.h> #include <arpa/inet.h> int main(){     char *addr1 = "192.168.1.1";     char *addr2 = "192.168.1.11";     unsigned long conv_addr = inet_addr(addr1);     if(conv_addr == INADDR_NONE){         puts("Error occured!");     }else{         printf("Network ordered integer addr: %#lx\n", conv_addr);     }     conv_addr = inet_addr(addr2);     if(conv_addr == INADDR_NONE){         puts("Error occured!");     }else{         printf("Network ordered integer addr: %#lx\n", conv_addr);     }     return 0; }


make inetaddr  
cc     inetaddr.c   -o inetaddr

./inetaddr
Network ordered integer addr: 0x101a8c0
Network ordered integer addr: 0xb01a8c0

From:http://c.biancheng.net/cpp/html/3047.html

作者：jackxiang@向东博客 专注WEB应用 构架之美 --- 构架之美，在于尽态极妍 | 应用之美，在于药到病除
地址：https://jackxiang.com/post/9581/
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