1、

2、

>>>   int socket(int af, int type,int protocol);//创建套接字，返回从文件描述表中取出新的索引号(int);AF_INET,SOCK_DGRAM/SOCK_STREAM,0；阻塞式socket

int close(int d);/int shutdown(int socket,int direction);//关闭

//将int s套接字转成nonblock

void nonblock(int s)

{

  int flags;

flags = fcntl(s, F_GETEL,0);//获取

flags != O_NONBLOCK;

if(fcntl(s,F_SETFL,flags)<0) exit(1);//设置

}

struct sockaddr{

u_short sa_family;

char sa_data[14];

}

struct in_addr{

u_long s_addr;

};

struct sockaddr_in{

short sin_family;

u_short sin_port;

struct in_addr sin_addr;

char sin_zero[8];

}

>>>  int connect(int s, const struct sock* name, socklen_t namelen);

int connectToServer(int sock)

{

struct sockaddr_in  s_addr_in;

s_addr_in.sin_family = AF_INET;

s_addr_in.sin_port = htos(8001);

s_addr_in.sin_addr.s_addr = inet_addr(“127.0.0.1”);//ip转为usigned long 二进步数，相反 char*  inet_ntoa(struct in_addr in);

if(connect(sock,(struct sockaddr*)&s_addr_in,sizeof(s_addr_in))<0)

        return 0;

return 1;

}

//域名转成long 类型二进制地址

unsigned long getaddrbydomain(char* addr)

{

struct hostent *ph;

struct in_addr in;

ph = gethostbyname(addr);

memcpy((char**)&(in),ph->_addr,ph->h_length);

return (in.s_addr);

}

struct hostent

{

char h_name;

char **h_aliases;

int h_addrtype;

int h_length;

char **h_addr_list;//名字服务器上的地址列表

}

>>>  int bind(int s, const struct sockaddr* addr, socklen_t addrlen);

>>>  int listen(int s, int backing);

>>>  int accept(int s, struct sockaddr *addr, socklen_t *addrlen);//返回分配到的套接字

>>>  ssize_t send(int s,const void *msg,size_t len, int flags);

>>>  int recv(int s, void *buf, size_t len, int flags);//buf 接收到的数据，返收的数据长度；flags{MSG_OOB,MSG_PEEK/*从receive_queue取出数据到buf后不删除原来的*/}

>>>  int write(int s, void *buf, size_t len);//与send相同

>>>  int read(int s, void *buf ,size_t len);//recv

>>>  int sendto (int s,const void *msg,size_t len, int flags, const struct sockaddr* to, socklen_t tolen);//相当于connect 与send组合

>>>  int recvfrom(int s, void *buf ,size_t len, int  flags, struct sockaddr* from, socklen_t  * fromlen);//相当于accept与recv合并

>>>  int select(int nfds, fd_set *readfds, fd_set * writefds, fd_set *exceptfds, struct timeval * timeout);

>>>   int setsockopt(int s,int level, int optname, const void* optval, unsigned int optlen);/getsockopt

>>>  void (*signal(int signum,void(*handler)(int)))int);

>>> errno

3. winsock

>>> int WASStartup(WORD wVersionRequest,LPWSADATA lpWSAData);

>>>  int WSACleanup();

struct WSAData {    WORD             wVersion;    WORD             wHighVersion;    char             szDescription[WSADESCRIPTION_LEN+1];    char             szSystemStatus[WSASYSSTATUS_LEN+1];    unsigned short   iMaxSockets;    unsigned short   iMaxUdpDg;    char FAR *       lpVendorInfo;

};

>>>  SOCKET socket(int af,int type,int protocol);

>>>  int closesocket(SOCKET s);

>>>  int ioctlsocket(SOCKET s,long cmd, u_long FAR* argp);//fcntl/ioctl

>>>  int connect(SOCKET s, const struct sockaddr FAR* name,int namelen);

>>>  int bind(SOCKET s, const struct sockaddr FAR* name,int namelen);

>>> int listen(SOCKET s, int backlog);

>>>  SOCKET accept( SOCKET s,struct sockaddr FAR*addr,int FAR*addrlen);

>>>  int send ( SOCKET s, const char FAR * buf, int len, int flags ); 

>>> int recv ( SOCKET s, char FAR* buf, int len, int flags ); 

>>> sendto /recvfrom

>>>  select/WSAAsyncSelect/WSAEventSelect

>>> getsockopt/setsockopt

>>>  WSAGetLastError