/* tcpclient.c */

#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>


int main()

{

        int sock, bytes_recieved;  
        char send_data[1024],recv_data[1024];
        struct hostent *host;
        struct sockaddr_in server_addr;  

		char header[15];

        host = gethostbyname("prueba");
		if ( host==NULL)
		{
		 printf (" no encuentro la direccion \n");
		}
		printf ("la direecion es %s  \n", host->h_addr_list );
			 printf("\n eNTRando en acCCioN...\n ");
        if ((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
            perror("Socket");
            exit(1);
        }

        server_addr.sin_family = AF_INET;     
        server_addr.sin_port = htons(5000);   
        server_addr.sin_addr = *((struct in_addr *)host->h_addr);
        bzero(&(server_addr.sin_zero),8); 
		
        if (connect(sock, (struct sockaddr *)&server_addr,
                    sizeof(struct sockaddr)) == -1) 
        {
            perror("Connect");
            exit(1);
        }

        while(1)
        {
          

		  printf("\n ES hora de mandar datos.. que desea enviar? (q or Q to quit) : ");
          gets(header);
				send_data[0]= 0x02;
				send_data[1]= 0x07;
				send_data[2]= 0x31;
				send_data[3]= 0x31;
				send_data[4]= 0x17;

			strcat (send_data,header);
				header[0]= 0x05;
				header[1]= '\0';
				strcat (send_data,header);
		  if (strcmp(send_data , "q") == 0 || strcmp(send_data , "Q") == 0)
              {
                send(sock, send_data,strlen(send_data), 0); 
                close(sock);
                break;
              }
               
              else
                 send(sock, send_data,strlen(send_data), 0);  

          bytes_recieved=recv(sock,recv_data,1024,0);
          recv_data[bytes_recieved] = '\0';
 
          if (strcmp(recv_data , "q") == 0 || strcmp(recv_data , "Q") == 0)
          {
           close(sock);
           break;
          }

          else
           printf("\nRecieved data = %s " , recv_data);
           
           printf("\nSEND (q or Q to quit) : ");
           gets(send_data);
           
          if (strcmp(send_data , "q") != 0 && strcmp(send_data , "Q") != 0)
           send(sock,send_data,strlen(send_data), 0); 

          else
          {
           send(sock,send_data,strlen(send_data), 0);   
           close(sock);
           break;
          }
        
        }   
return 0;
}

ulcmx1:oasys:prueba> make new
--- Completed TARGET=clean:/usr/oasys/V5.2.2/source/project/simcot/prueba./HP/
--- Completed TARGET=depend:/usr/oasys/V5.2.2/source/project/simcot/prueba
Lib
--- Completed TARGET=LIB:/usr/oasys/V5.2.2/source/project/simcot/prueba
        cc  -c -DHP -DSYSTEM_10 +u4 -DSAMMI3 -I/usr/oasys/V5.2.2/source/include/auto/HP -I/usr/oasys/V5.2.2/source/include/user -Aa tcp.c -o ./HP/tcp.o
cc: "tcp.c", line 29: error 1574: Unknown size for "server".
cc: "tcp.c", line 30: error 1594: The sizeof operator cannot be applied to types with unknown size.
cc: "tcp.c", line 50: error 1588: "AF_INET" undefined.
cc: "tcp.c", line 50: error 1588: "SOCK_STREAM" undefined.
cc: "tcp.c", line 68: error 1530: Undefined struct or union.
cc: "tcp.c", line 73: error 1530: Undefined struct or union.
cc: "tcp.c", line 73: error 1529: Cannot select field of non-structure.
cc: "tcp.c", line 73: error 1588: "INADDR_ANY" undefined.
*** Error exit code 1