matlab中connect函数用法?

Question

matlab中connect函数用法

Answer 1

　connect()用于建立与指定socket的连接。　　头文件: #include <winsock.h>　　函数原型: int PASCAL FAR connect( SOCKET s, const struct sockaddr FAR* name, int namelen);　　参数:　　s：标识一个未连接socket　　name：指向要连接套接字的sockaddr结构体的指针　　namelen：sockaddr结构体的字节长度　　注释：　　本函数用于创建与指定外部端口的连接。s参数指定一个未连接的数据报或流类套接口。如套接口未被捆绑，则系统赋给本地关联一个唯一的值，且设置套接口为已捆绑。请注意若名字结构中的地址域为全零的话，则connect()将返回WSAEADDRNOTAVAIL错误。　　对于流类套接口（SOCK_STREAM类型），利用名字来与一个远程主机建立连接，一旦套接口调用成功返回，它就能收发数据了。对于数据报类套接口（SOCK_DGRAM类型），则设置成一个缺省的目的地址，并用它来进行后续的send()与recv()调用。　　返回值：　　若无错误发生，则connect()返回0。否则的话，返回SOCKET_ERROR错误，应用程序可通过WSAGetLastError()获取相应错误代码。对非阻塞套接口而言，若返回值为SOCKET_ERROR则应用程序调用WSAGetLsatError()。如果它指出错误代码为WSAEWOULDBLOCK，则您的应用程序可以：　　1.用select()，通过检查套接口是否可写，来确定连接请求是否完成。　　2.如果您的应用程序使用基于消息的WSAAsynSelect()来表示对连接事件的兴趣，则当连接操作完成后，您会收到一个FD_CONNECT消息。　　错误代码：　　WSAENOTINITIALISED：在使用此API之前应首先成功地调用WSAStartup()。　　WSAENETDOWN：WINDOWS套接口实现检测到网络子系统失效。　　WSAEADDRINUSE：所指的地址已在使用中。　　WSAEINTR：通过一个WSACancelBlockingCall()来取消一个（阻塞的）调用。　　WSAEINPROGRESS：一个阻塞的WINDOWS套接口调用正在运行中。　　WSAEADDRNOTAVAIL：在本地机器上找不到所指的地址。　　WSAENOTSUPPORT：所指族中地址无法与本套接口一起使用。　　WSAECONNREFUSED：连接尝试被强制拒绝。　　WSAEDESTADDREQ：需要目的地址。　　WSAEFAULT：namelen参数不正确。　　WSAEINVAL：套接口没有准备好与一地址捆绑。　　WSAEISCONN：套接口早已连接。　　WSAEMFILE：无多余文件描述字。　　WSAENETUNREACH：当前无法从本主机访问网络。　　WSAENOBUFS：无可用缓冲区。套接口未被连接。　　WSAENOTSOCK：描述字不是一个套接口。　　WSAETIMEOUT：超时时间到。　　WSAEWOULDBLOCK：套接口设置为非阻塞方式且连接不能立即建立。可用select()调用对套接口写，因为select()时会进行连接。

Answer 2

connect Block-diagram interconnections of dynamic systems.connect computes an aggregate model for a block diagram interconnectionof dynamic systems. You can specify the block diagram connectivity intwo ways:Name-based interconnectionIn this approach, you name the input and output signals of all blocksSYS1, SYS2,... in the block diagram, including the summation blocks.The aggregate model SYS is then built bySYS = connect(SYS1,SYS2,...,INPUTS,OUTPUTS)where INPUTS and OUTPUTS are the names of the block diagram externalI/Os (specified as strings or string vectors).Example 1: Given SISO models C and G, you can construct the closed-looptransfer T from r to y usinge ur --->O-->[ C ]---[ G ]-+---> y- | |+<----------------+C.InputName = 'e'; C.OutputName = 'u';G.InputName = 'u'; G.OutputName = 'y';Sum = sumblk('e = r-y');T = connect(G,C,Sum,'r','y')Example 2: If C and G above are two-input, two-output models instead,you can form the MIMO transfer T from r to y usingC.u = 'e'; C.y = 'u';G.u = 'u'; G.y = 'y';Sum = sumblk('e = r-y',2);T = connect(G,C,Sum,'r','y')Note that C.u,C.y is shorthand for C.InputName,C.OutputName and that'r','y' select all entries of the two-entry vector signals r and y.Example 3: If you already have specified I/O names for C and G, youcan build the closed-loop model T using:Sum = sumblk('%e = r - %y',C.u,G.y);T = connect(G,C,Sum,'r',G.y)See SUMBLK for more details on using aliases like %e and %y.Index-based interconnectionIn this approach, first combine all system blocks into an aggregate,unconnected model BLKSYS using APPEND. Then construct a matrix Qwhere each row specifies one of the connections or summing junctionsin terms of the input vector U and output vector Y of BLKSYS. Forexample, the row [3 2 0 0] indicates that Y(2) feeds into U(3), whilethe row [7 2 -15 6] indicates that Y(2) - Y(15) + Y(6) feeds into U(7).The aggregate model SYS is then obtained bySYS = connect(BLKSYS,Q,INPUTS,OUTPUTS)where INPUTS and OUTPUTS are index vectors into U and Y selecting theblock diagram external I/Os.Example: You can construct the closed-loop model T for the blockdiagram above as follows:BLKSYS = append(C,G);% U = inputs to C,G. Y = outputs of C,G% Here Y(1) feeds into U(2) and -Y(2) feeds into U(1)Q = [2 1; 1 -2];% External I/Os: r drives U(1) and y is Y(2)T = connect(BLKSYS,Q,1,2)Note:* connect always returns a state-space or FRD model SYS* States that do not contribute to the I/O transfer from INPUTS toOUTPUTS are automatically discarded. To prevent this, set the"Simplify" option to FALSE:OPT = connectOptions('Simplify',false);SYS = connect(...,OPT)