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POsocket recv in thread , wrong behavior
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copied!<p>Greeting !!</p> <p>I use unpv13e library in linux developed as socket server , and listen a port which will accept 3 socket clients (at most) , each client would has its own thread ....</p> <p>While these 3 clients send very very quick , the recv function of socket server will receive said half of string came from client1 , half of another came from client2 , it is odd because I think these 3 socket clients would be run in different thread , also different socket id , so I am curious why it happened ? let me explain in the following codes :</p> <pre><code>listenfd = Tcp_listen(ipaddr,portno,&addrlen); cliaddr = Malloc(addrlen); Signal(SIGINT, sig_int); for ( ; ; ) { clilen = addrlen; connfd = Accept(listenfd, cliaddr, &clilen); err_msg("id [%05d] conned from %s",connfd,Sock_ntop(cliaddr, clilen)); Pthread_create(&tid, NULL, &doit, (void *) connfd); } void * doit(void *arg) { void web_child(int); Pthread_detach(pthread_self()); web_child((int) arg); Close((int) arg); printf("thread [%05d] dead...\n",(int) arg); return(NULL); } void web_child(int sockfd) { int connfd; ssize_t nread; char line[1024]; for ( ; ; ) { line[0]=0x00 ; if ( (nread = Readline(sockfd, line, 1024)) == 0) break; /* connection closed by other end */ line[nread-2]=0x00 ; if(strncmp(line,"101",3)==0) Do101(line) ; if(strncmp(line,"201",3)==0) Do201(line) ; if(strncmp(line,"301",3)==0) Do301(line) ; } } </code></pre> <p>Readline function in unpv13e library call recv , and check one char at a time until it is a '\n' and return , the nread usually 315 bytes or so , and I do not have send in this socket server !! In my opinion , web_child function is run as thread , with different socketfd , and line is local var , so it is no way that 3 different client will effect each other, socket client1 will always send string start with "101" , and client2 always send "201", client3 send "301" ....</p> <p>But somestimes I'll see a string in Do101(line) , which the firat half of it is "101" , and second half of it came from client2 , they just effect each other ... if these 3 clients send very very frequently , it might happened ... not very often , but it just happened !!</p> <p>What kind of bug I've in the code ? recv from different socketid in different thread will effect each other ? </p> <p>Any suggestion are welcome !! Thanks !!</p>

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