Need help about read() and write() on TCP/IP Post: 302469543

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Top Forums Programming Need help about read() and write() on TCP/IP Post 302469543 by lixiao1212 on Saturday 6th of November 2010 10:27:09 PM

11-06-2010

Registered User

Need help about read() and write() on TCP/IP

HI

I need to implement a client/server TCP application. the customer is the client and the bartender is the server.

When the customer enter the Bar, client connects to the server
Server should reply the client immediately. Other wise if the server is busy, it should send an update message every 10 seconds.

Depending on which message replied by the server:

10 seconds expired, no reply: client leave, that is disconnect
server is busy update: client reply --waiting or "leave and disconnect"
select beer: client reply -- light or black
select quantity: client reply liter or bottle, then disconnect

I have done the part before 'connection', but i don't know how to complement the function about read() and write(), so, please help me have a look at it, many thanks!!

Code:

#include <sys/wait.h>
#include <malloc.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <errno.h>
#include <stdlib.h>
#include <arpa/inet.h>
int main(int argc, char *argv[])
{
    int   socket1,n;   
        int blond=0 , brun=0;//string buf;
    char buffer[256];
    if(argc<2) {
        printf ("usage socket_clt \n");
        exit(0);
    }
 
    printf("client1 is coming\n");
        struct sockaddr_in local;
        struct sockaddr_in from;
        int fromlen =sizeof(from);
    bzero(&from, sizeof(from));
        from.sin_family=AF_INET;
        from.sin_port=htons(5000); //lisening 5000
        from.sin_addr.s_addr=INADDR_ANY; //address of local computer
    /*creat a socket*/   
    if (( socket1=socket(AF_INET, SOCK_STREAM,0))<0)
         {
        printf("socket error ourverture\n");exit(0);
    }
 
    if (connect(socket1, (struct sockaddr*)&from, sizeof(from))<0)
         {
        printf("socket error connection\n");
        exit(0);
    }
 
    bzero(buffer,256);
      fgets(buffer,255,stdin);
      n = write(socket1,buffer,strlen(buffer));
      if (n < 0)
           error("ERROR writing to socket");
 
  bzero(buffer,256);
      n = read(socket1,buffer,255);
      if (n < 0)
           error("ERROR reading from socket");
      printf("%s\n",buffer);
      return 0;
 
}

I need to add a function of 'timeout' on read(),but i don't know how to do that.
thus how can i add a circle to implement many customers entering?

Last edited by lixiao1212; 11-07-2010 at 03:20 PM.. Reason: Please use code tags

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LEARN ABOUT LINUX

ic_c_protocol

ic_c_protocol(3erl)						C Library Functions					       ic_c_protocol(3erl)

NAME

       ic_c_protocol - IC C Protocol Functions

DESCRIPTION

       This manual page lists some of the functions of the IC C runtime library that are used internally for the IC protocol.

       The listed functions are used internally by generated C client and server code. They are documented here for the advanced user that want to
       replace the default protocol (Erlang distribution + gen_server) by his own protocol, For each set of client or sever functions  below  with
       prefix  oe , the user has to implement his own set of functions, the names of which are obtained by replacing the oe prefix by Prefix . The
       Prefix has to be set with the option {user_protocol, Prefix} at compile time.

       The following terminology is used (reflected in names of functions): a notification is a message send from client to  server,  without  any
       reply  back  (i.e.  a oneway operation); a request is a message sent from client to server, and where a reply message is sent back from the
       server to the client.

       In order to understand how the functions work and what they do the user must study their implementation in the IC C library (source file is
       ic.c ), and also consider how they are used in the C code of ordinary generated client stubs or server skeletons.

CLIENT PROTOCOL FUNCTIONS

       The following functions are used internally by generated C client code.

EXPORTS

       int oe_prepare_notification_encoding(CORBA_Environment *env)

	      The  result  of  this  function  is the beginning of a binary of in external format of the tuple {'$gen_cast', X} where X is not yet
	      filled in.

	      In generated client code this function is the first to be called in the encoding function for each oneway operation.

       int oe_send_notification(CORBA_Environment *env)
       int oe_send_notification_tmo(CORBA_Environment *env, unsigned int send_ms)

	      Sends a client notification to a server according to the Erlang distribution + gen_server protocol.

	      The send_ms parameter specified a timeout in milliseconds.

       int oe_prepare_request_encoding(CORBA_Environment *env)

	      The result of this function is the beginning of a binary in the external format of the tuple {'$gen_call', {Pid, Ref}, X} where X is
	      not yet filled in.

	      In generated client code this function is the first to be called in the encoding function for each twoway operation.

       int oe_send_request_and_receive_reply(CORBA_Environment *env)
       int oe_send_request_and_receive_reply_tmo(CORBA_Environment *env, unsigned int send_ms, unsigned int recv_ms)

	      Sends  a	client	request and receives the reply according to the Erlang distribution + gen_server protocol. This function calls the
	      oe_prepare_reply_decoding function in order to obtain the gen_server reply.

	      send_ms and recv_ms specify timeouts for send and receive, respectively, in milliseconds.

       int oe_prepare_reply_decoding(CORBA_Environment *env)

	      Decodes the binary version of the tuple {Ref, X} , where X is to be decoded later by the specific client decoding function.

SERVER PROTOCOL FUNCTIONS

       The following functions are used internally by generated C server code.

EXPORTS

       int oe_prepare_request_decoding(CORBA_Environment *env)

	      Decodes the binary version of the tuple {'$gen_cast', Op} ( Op an atom), or the tuple {'$gen_cast', {Op, X}} , where Op is the oper-
	      ation name, and where X is to be decoded later by the specific operation decoding function; or

	      decodes the binary version of the tuple {'$gen_call', {Pid, Ref}, Op} ( Op an atom), or the tuple {'$gen_call', {Pid, Ref}, {Op, X}}
	      , where Op> is the operation name, and X is to be decode later by the specific operation decoding function.

       int oe_prepare_reply_encoding(CORBA_Environment *env)

	      Encodes the beginning of the binary version of the tuple {{Ref,X} , where X is to be filled in by the specific server encoding func-
	      tion.

SEE ALSO

       ic(3erl), ic_clib(3erl), IC Protocol

Ericsson AB							     ic 4.2.26						       ic_c_protocol(3erl)

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