Search Results

Search found 7065 results on 283 pages for 'cpu sockets'.

Page 69/283 | < Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >

  • how to print a char od struct()

    - by make
    Hi Could someone please tell us to print a char when receiving data as a truct? here is an EXP: ... struct rcv{ int x1; float x2; char x3; }; rcv data_rcv; ... if (recv(socket, &data_rcv, sizeof(data_rcv), 0) < 0) printf("recv() failed"); ... printf("x1 = %d\n", data_rcv.x1); printf("x2 = %f\n", data_rcv.x2); printf("x3 = %s\n", data_rcv.x3); // it doesn't print anything, why? ... Thanks for your replies-

    Read the article

  • First time using select(), maybe a basic question?

    - by darkletter
    Hello people, i've been working for a few days with this server using select(). What it does, is that, i have two arrays of clients (one is "suppliers", and the other is "consumers"), and the mission of the server is to check whether the suppliers have something to send to the consumers, and in case affirmative, send it. The second part of the server is that, when the consumers have received the suppliers' info, they send a confirmation message to the same suppliers that sent the info. When a client connects, it gets recognized as "undefined", until it sends a message with the word "supplier" or "consumer" (in Spanish, as i'm from there), when the server puts it in the correct clients array. Well, what the server does is not very important here. What's important is that, i'm doing both parts with two different "for" loops, and that's where i'm getting the problems. When the first user connects to the server (be it a supplier or a consumer), the server gets stuck in the first or second loop, instead of just continuing its execution. As it's the first time i'm using select(), i may be missing something. Could you guys give me any sort of help? Thanks a lot in advance. for(;;) { rset=allset; nready=select(maxfd+1,&rset,NULL,NULL,NULL); if (FD_ISSET(sockfd, &rset)){ clilen=sizeof(cliente); if((connfd=accept(sockfd,(struct sockaddr *)&cliente,&clilen))<0) printf("Error"); IP=inet_ntoa(cliente.sin_addr); for(i=0;i<COLA;i++){if(indef[i]<0){indef[i]=connfd;IPind[i]=IP;break;}} FD_SET(connfd,&allset); if(connfd > maxfd) maxfd=connfd; if(i>maxii) maxii=i; if(--nready<=0) continue; }// Fin ISSET(sockfd) for(i=0;i<=maxii;i++){ if((sockfd1=indef[i])<0){ continue;} //! if(FD_ISSET(sockfd1,&rset)){ if((n=read(sockfd1,comp,MAXLINE))==0){close(sockfd1);FD_CLR(sockfd1,&allset);indef[i]=-1;printf("Cliente indefinido desconectado \n");} else{ comp[n]='\0'; if(strcmp(comp,"suministrador")==0){ for(j=0;j<=limite;j++){if(sumi[j]<0){IPsum[j]=IPind[i];sumi[j]=indef[i]; indef[i]=-1;if(j>maxis) {maxis=j;}break; } } } else if(strcmp(comp,"consumidor")==0){ for(o=0;j<=limite;j++){if(consum[o]<0){IPcons[o]=IPind[i];consum[o]=indef[i]; indef[o]=-1;if(o>maxic) {maxic=o;}break; } } } if(--nready <=0)break; } } }//fin bucle for maxii for(i=0;i<=maxis;i++){ if((sockfd2=sumi[i])<0){continue;} if(FD_ISSET(sockfd2,&rset)){ if((n=read(sockfd2,buffer2,MAXLINE))==0){close(sockfd2);FD_CLR(sockfd2,&allset);sumi[i]=-1;printf("Suministrador desconectado \n");} else{ buffer2[n]='\0'; for(j=0;j<=maxic;j++){ if((sockfd3=consum[j])<0){ continue;} else {strcpy(final,IPsum[i]);strcat(final,":");strcat(final,buffer2);write(sockfd3,final,sizeof(final));respuesta[i]=1;} } break; // ? } } }//fin for maxis for(i=miniic;i<=maxic;i++){ if((sockfd4=consum[i])<0){continue;} if(FD_ISSET(sockfd4,&rset)){ if((n=read(sockfd4,buffer3,MAXLINE))==0){close(sockfd4);FD_CLR(sockfd4,&allset);consum[i]=-1;printf("Consumidor desconectado \n");} else{ buffer3[n]='\0'; IP2=strtok(buffer3,":"); obj=strtok(NULL,":"); for(j=0;j<100;j++){ if((strcmp(IPsum[j],IP2)==0) && (respuesta[j]==1)) {write(sumi[j],obj,sizeof(obj)); miniic=i+1; respuesta[j]=0; break; } } } } }

    Read the article

  • Strange numbers in java socket output

    - by user293163
    I have small test app: Socket socket = new Socket("jeck.ru", 80); PrintWriter pw = new PrintWriter(socket.getOutputStream(), false); pw.println("GET /ip/ HTTP/1.1"); pw.println("Host: jeck.ru"); pw.println(); pw.flush(); BufferedReader rd = new BufferedReader(new InputStreamReader(socket.getInputStream())); String str; while ((str = rd.readLine()) != null) { System.out.println(str); } It`s output: HTTP/1.1 200 OK Date: Sat, 13 Mar 2010 22:06:51 GMT Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked Connection: keep-alive Keep-Alive: timeout=5 Server HTTP/1.1 200 OK Date: Sat, 13 Mar 2010 22:06:51 GMT Content-Type: text/html;charset=utf-8 Transfer-Encoding: chunked Connection: keep-alive Keep-Alive: timeout=5 Server: Apache Cache-Control: max-age=0 Expires: Sat, 13 Mar 2010 22:06:51 GMT 123 <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <title>??? IP</title> </head> <body> <div style='text-align: center; font: 32pt Verdana;margin-top: 300px'> ??? IP &#151; 94.103.87.153 </div> </body> </html> 0 Whence these numbers (123 an 0) takes?

    Read the article

  • How can I forcibly close a TcpListener

    - by Nissim
    I have a service which communicates through tcpListener. Problem is when the user restarts the service - an "Address already in use" exception is thrown, and the service cannot be started for a couple of minutes or so. Is there's any way of telling the system to terminate the old connection so I can open a new one? (I can't just use random ports because there is no way for the service to notify the clients what is the port, so we must depend on a predefined port)

    Read the article

  • Reason for socket.error

    - by August Flanagan
    Hi, I am a complete newbie when it comes to python, and programming in general. I've been working on a little webapp for the past few weeks trying to improve my coding chops. A few days ago my laptop was stolen so I went out and got a new MacBook Pro. Thank God I had everything under subversion control. The problem is now that I am on my new machine a script that I was running has stopped working and I have no idea why. This is really the only part of what I have been writing that I borrowed heavily for existing scripts. It is from the widely available whois.py script and I have only slightly modified it as follows (see below). It was running fine on my old system (running ubuntu), but now the socket.error is being raised. I'm completely lost on this, and would really appreciate any help. Thanks! def is_available(domainname, whoisserver="whois.verisign-grs.com", cache=0): if whoisserver is None: whoisserver = "whois.networksolutions.com" s = None while s == None: try: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.setblocking(0) try: s.connect((whoisserver, 43)) except socket.error, (ecode, reason): if ecode in (115, 150): pass else: raise socket.error, (ecode, reason) ret = select.select([s], [s], [], 30) if len(ret[1])== 0 and len(ret[0]) == 0: s.close() raise TimedOut, "on connect " s.setblocking(1) except socket.error, (ecode, reason): print ecode, reason time.sleep(1) s = None s.send("%s \n\n" % domainname) page = "" while 1: data = s.recv(8196) if not data: break page = page + data s.close()

    Read the article

  • Hold a network connection although IP address change

    - by rursw1
    Hi, Is it possible to hold an open TCP connection with a client, while the IP address of the client is externally changed? For example, the connection is establishes against address X, but somewhen while the connection is open, the client-side user asks for IP renew and gets another IP address. Can the connection remains alive in this case? Thanks in advance.

    Read the article

  • How Proxy server works with tcp/http connections?

    - by Vivek
    Since I am a beginner in the world of internet/networking, I always mess up with these kinds of doubts in my head while programming ;) .. My doubts are, While working behind a proxy, how my requests and responses work? Means my request headers and data will first reach to Proxy server- then proxy server sends it(same headers and data) to corresponding server. And server responses to it with a response header and body to the proxy server-then proxy server sends it to my computer. Wright? While using websockets we are upgrading our http connection to tcp. At this time what is happening @ Proxy server? Does the proxyserver also upgrades its connection to plain TCP? After opening such TCP connections, does the proxy server able to track/log those socket messsages? And most importantly, Is the proxy server transparent or acting like an original server infront of a client? Thanks for any answers or helpful links in advance.

    Read the article

  • Reading TCP Sequence Number Before Sending a Packet

    - by Sadeq Dousti
    I'm writing a C/C++ client-server program under Linux. Assume a message m is to be sent from the client to the server. Is it possible for the client to read the TCP sequence number of the packet which will carry m, before sending m? In fact, I'd like to append this sequence number to m, and send the resulting packet. (Well, things are more complicated, but let's keep it that simple. In fact, I'd like to apply authentication info to this sequence number, and then append it to m.) Moreover, is it possible for the server to read the TCP sequence number of the packet carrying m?

    Read the article

  • What happens to an instance of ServerSocket blocked inside accept(), when I drop all references to i

    - by Hanno Fietz
    In a multithreaded Java application, I just tracked down a strange-looking bug, realizing that what seemed to be happening was this: one of my objects was storing a reference to an instance of ServerSocket on startup, one thread would, in its main loop in run(), call accept() on the socket while the socket was still waiting for a connection, another thread would try to restart the component under some conditions, the restart process missed the cleanup sequence before it reached the initialization sequence as a result, the reference to the socket was overwritten with a new instance, which then wasn't able to bind() anymore the socket which was blocking inside the accept() wasn't accessible anymore, leaving a complete shutdown and restart of the application as the only way to get rid of it. Which leaves me wondering: with no references left to the ServerSocket instance, what would free the socket for a new connection? At what point would the ServerSocket become garbage collected? In general, what are good practices I can follow to avoid this type of bug?

    Read the article

  • Concurrent connections in C# socket

    - by Chu Mai
    There are three apps run at the same time, 2 clients and 1 server. The whole system should function as following: The client sends an serialized object to server then server receives that object as a stream, finally the another client get that stream from server and deserialize it. This is the sender: TcpClient tcpClient = new TcpClient(); tcpClient.Connect("127.0.0.1", 8888); Stream stream = tcpClient.GetStream(); BinaryFormatter binaryFormatter = new BinaryFormatter(); binaryFormatter.Serialize(stream, event); // Event is the sending object tcpClient.Close(); Server code: TcpListener listener = new TcpListener(IPAddress.Parse("127.0.0.1"), 8888); listener.Start(); Console.WriteLine("Server is running at localhost port 8888 "); while (true) { Socket socket = listener.AcceptSocket(); try { Stream stream = new NetworkStream(socket); // Typically there should be something to write the stream // But I don't knwo exactly what should the stream write } catch (Exception e) { Console.WriteLine("Exception: " + e.Message); Console.WriteLine("Disconnected: {0}", socket.RemoteEndPoint); } } The receiver: TcpClient client = new TcpClient(); // Connect the client to the localhost with port 8888 client.Connect("127.0.0.1", 8888); Stream stream = client.GetStream(); Console.WriteLine(stream); when I run only the sender and server, and check the server, server receives correctly the data. The problem is when I run the receiver, everything is just disconnected. So where is my problem ? Could anyone point me out ? Thanks

    Read the article

  • Interview Questions that can be asked on TCP/IP, UDP, Socket Programming ?

    - by Shantanu Gupta
    I am going for an interview day after tomorrow where i will be asked vaious questions related to TCP/IP and UDP. As of now i have prepared theoritical knowledge about it. But now I am looking up for gaining some practicle knowledge related to how it works in a network. What all is going in vaious .NET classes. I want to create a very small application like a chat or something that can make me all these concepts very much clear. Could you please suggest some questions related to TCP/IP that you generally ask or that you might have faced. How communication is going from server to client. Right now I am studying TcpClient, TcpListener and UdpClient Class but I want to implement all of them so as to get aware about its working. Is Chat application a Tcp/IP application ? I would appreciate your help.

    Read the article

  • Receive input over TCP/IP and use it to update HTML

    - by mawg
    This has got to be a FAQ, so can someone please just direct me to a "network programming for dummies" URL? The server wants to push information to a client or broadcast to all, when an event happens - as opposed to the clients constantly polling the server "just in case". The client then updates a browser page display. How do I do that? (toldya it was a n00b question) Should I have a thread which receives info on a socket and then writes it to a database which the browser display (PHP) can process with an HTML refresh tag, or what? Sorry to sound so dumb.

    Read the article

  • Why can't a bind linux service to the loop-back only?

    - by Jon Trauntvein
    I am writing a server application that will provide a service on an ephemeral port that I only want accessible on the loopback interface. In order to do this, I am writing code like the following: struct sockaddr_in bind_addr; memset(&bind_addr,0,sizeof(bind_addr)); bind_addr.sin_family = AF_INET; bind_addr.sin_port = 0; bind_addr.sin_addr.s_addr = htonl(inet_addr("127.0.0.1")); rcd = ::bind( socket_handle, reinterpret_cast<struct sockaddr *>(&bind_addr), sizeof(bind_addr)); The return value for this call to bind() is -1 and the value of errno is 99 (Cannot assign requested address). Is this failing because inet_addr() already returns its result in network order or is there some other reason?

    Read the article

  • udp server unable to transmit data

    - by mawia
    Hi! all, I have written a simple udp server which has to transmit certain data to few of it's clients. but though server is successfully executing send,but unable to transmit even a single byte.The return value of send is 0 although I have enough data to be transmitted.you can see the code for the said server here: http://pastebin.com/zeMcwd6X Can you people help in finding the possible culprit for the same.Any reply in this regard will be appreciated. Lot of Thanks in advance! Mawia

    Read the article

  • python send/receive hex data via TCP socket

    - by Mike
    I have a ethenet access control device that is said to be able to communicate via TCP. How can i send a pachet by entering the HEX data, since this is what i have from their manual (a standard format for the communication packets sent and received after each command)

    Read the article

  • Does Socket open another thread? Does it return something?

    - by Roman
    In the client application I call new Socket(serverIP,serverPort). As a result the client application sends a request to the server application to open a socket. Does it start a new thread? I mean which of the following is true? Client application sends a request and immediately starts to execute following commands (not weighting for the answer). Client sends the request and weights for the answer. As soon as the answer is obtained, the client application continues to execute following commands. The second case seems to be more realistic and logical for me. However, I do not understand what happens if the server does not open a socket and it does not say that it does not "want" to open the second (it can happen if the server does not exist or network is broken). What will happen in this case? Will server weight forever? In general it would be nice for the client to know what is the result of its request for the socket. For example I can imagine the following situations: The socket is opened by the server. The server refuses to open a socket. So, server exists, it got the request from the client but it says "no". There is no response from the server. I know that new Socket(serverIP,serverPort) does not "return" this kind of information. But it throws exceptions. One of them is "UnkownHostException". When it is thrown? When the server is not responding for a while (for how long)? ADDED: I just found out that UnknownHostException is thrown to indicate that the IP address of a host could not be determined. So, it is unrelated with the above described situations (server is not responding, server refuses to open a socket).

    Read the article

  • [java] Threading socket handler for two sided communication in tcp port

    - by raven
    I want to make a chat which will be programed in java. one computer will host the server and the other one will initiate the socket [tcp port]. now from what I read there should be a loop that will constantly read the socket which means it will make the code stuck. I have a button that is 'actionperformed' on mouse release, I want to know if it will work along with the loops that constantly reads the socket so that it will also send the infromation I wrote. If I must thread it, I want to know if the run() method must be void because if I thread it it will mean creating a new class, and the whole GUI is one big class which includes a text area, and it's private. also how can I extract the information from the socket directly to the text area? lets say the textarea variable is called "chatOutput". thx :)

    Read the article

  • [Errno 10061] No connection could be made because the target machine actively refused it

    - by user551717
    I've tried to connect to my local machine every time I try and run my program. I am a nub, so it's probably a simple mistake somewhere. def connect(self): self.conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM) self.conn.connect((self.host,self.port)) That is the code causing the error. The host and port are defined. Why is it giving me this error report? [Errno 10061] No connection could be made because the target machine actively refused it

    Read the article

  • Use of select or multithread for almost 80 or more clients?

    - by Tushar Goel
    I am working on one project in which i need to read from 80 or more clients and then write their o/p into a file continuously and then read these new data for another task. My question is what should i use select or multithreading? Also I tried to use multi threading using read/fgets and write/fputs call but as they are blocking calls and one operation can be performed at one time so it is not feasible. Any idea is much appreciated. update 1: I have tried to implement the same using condition variable. I able to achieve this but it is writing and reading one at a time.When another client tried to write then it cannot able to write unless i quit from the 1st thread. I do not understand this. This should work now. What mistake i am doing? Update 2: Thanks all .. I am able to succeeded to get this model implemented using mutex condition variable. updated Code is as below: **header file******* char *mailbox ; pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER ; pthread_cond_t writer = PTHREAD_COND_INITIALIZER; int main(int argc,char *argv[]) { pthread_t t1 , t2; pthread_attr_t attr; int fd, sock , *newfd; struct sockaddr_in cliaddr; socklen_t clilen; void *read_file(); void *update_file(); //making a server socket if((fd=make_server(atoi(argv[1])))==-1) oops("Unable to make server",1) //detaching threads pthread_attr_init(&attr); pthread_attr_setdetachstate(&attr,PTHREAD_CREATE_DETACHED); ///opening thread for reading pthread_create(&t2,&attr,read_file,NULL); while(1) { clilen = sizeof(cliaddr); //accepting request sock=accept(fd,(struct sockaddr *)&cliaddr,&clilen); //error comparison against failire of request and INT if(sock==-1 && errno != EINTR) oops("accept",2) else if ( sock ==-1 && errno == EINTR) oops("Pressed INT",3) newfd = (int *)malloc(sizeof(int)); *newfd = sock; //creating thread per request pthread_create(&t1,&attr,update_file,(void *)newfd); } free(newfd); return 0; } void *read_file(void *m) { pthread_mutex_lock(&lock); while(1) { printf("Waiting for lock.\n"); pthread_cond_wait(&writer,&lock); printf("I am reading here.\n"); printf("%s",mailbox); mailbox = NULL ; pthread_cond_signal(&writer); } } void *update_file(int *m) { int sock = *m; int fs ; int nread; char buffer[BUFSIZ] ; if((fs=open("database.txt",O_RDWR))==-1) oops("Unable to open file",4) while(1) { pthread_mutex_lock(&lock); write(1,"Waiting to get writer lock.\n",29); if(mailbox != NULL) pthread_cond_wait(&writer,&lock); lseek(fs,0,SEEK_END); printf("Reading from socket.\n"); nread=read(sock,buffer,BUFSIZ); printf("Writing in file.\n"); write(fs,buffer,nread); mailbox = buffer ; pthread_cond_signal(&writer); pthread_mutex_unlock(&lock); } close(fs); }

    Read the article

  • Why use an event cache with epoll_wait?

    - by user1827356
    Question: epoll man page has some pointers when using epoll with an 'event cache'. But, why would you need to maintain an event cahce at all - Isn't this the same as what epoll is supposed to be doing? Is it to avoid making multiple epoll_wait calls which might be slower than managing the events in user space? Is it to implement a custom 'priority' scheme over the cached events? Background: I'm trying to understand the strengths/shortcomings of epoll and its applicability to different situations

    Read the article

  • Java blocking socket returning incomplete ByteBuffer

    - by evandro-carrenho
    I have a socketChannel configured as blocking, but when reading byte buffers of 5K from this socket, I get an incomplete buffer sometimes. ByteBuffer messageBody = ByteBuffer.allocate(5*1024); messageBody.mark(); messageBody.order(ByteOrder.BIG_ENDIAN); int msgByteCount = channel.read(messageBody); Ocasionally, messageBody is not completely filled and channel.read() does not return -1 or an exception, but the actual number of bytes read (which is less than 5k). Has anyone experienced a similar problem?

    Read the article

  • scoket connection issue+php

    - by Abhimanyu
    Hi, I am using PHP socket programming and able to write data to open socket but i have to wait for a long time(or stuck it)for the response or some time getting error like "Maximum execution time of 30 seconds exceeded line number where this code is placed fgets($fp, 128), i have check the server it seems it has sent the response as expected but i am not getting why i m unable to get response.following the code using for socket connection and reading data. functon scoket_connection() { $fp = fsockopen(CLIENT_HOST,CLIENT_PORT, $errno, $errstr); fwrite($fp,$packet); $msg = fgets($fp, 128); fclose($fp) return $msg; } any idea???

    Read the article

  • trying to WHOIS a site within IRC

    - by SourD
    if data.find('!whois') != -1: s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect(("com.whois-servers.net", 43)) s.send('www.msn.com' + "\r\n") response = '' while True: d = s.recv(4096) response += d if d == '': break s.send('PRIVMSG ' + chan + " " + response + '\r\n') s.close() when I type !whois on the channel, it doesnt do anything, I'm probably doing this wrong. Any help will be appreciate it. Thanks. Note: There's another socket already connected.

    Read the article

< Previous Page | 65 66 67 68 69 70 71 72 73 74 75 76  | Next Page >