Listing 2. Example Client Code
/*
* Listing 2:
* An example client for "Hello, World!" server
* Ivan Griffin (ivan.griffin@ul.ie)
*/
#include <stdio.h> /* perror() */
#include <stdlib.h> /* atoi() */
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h> /* read() */
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
int main(int argc, char *argv[])
{
int clientSocket,
remotePort,
status = 0;
struct hostent *hostPtr = NULL;
struct sockaddr_in serverName = { 0 };
char buffer[256] = "";
char *remoteHost = NULL;
if (3 != argc)
{
fprintf(stderr, "Usage: %s <serverHost>
<serverPort>\n",
argv[0]);
exit(1);
}
remoteHost = argv[1];
remotePort = atoi(argv[2]);
clientSocket = socket(PF_INET, SOCK_STREAM,
IPPROTO_TCP);
if (-1 == clientSocket)
{
perror("socket()");
exit(1);
}
/*
* need to resolve the remote server name or
* IP address */
hostPtr = gethostbyname(remoteHost);
if (NULL == hostPtr)
{
hostPtr = gethostbyaddr(remoteHost,
strlen(remoteHost), AF_INET);
if (NULL == hostPtr)
{
perror("Error resolving server address");
exit(1);
}
}
serverName.sin_family = AF_INET;
serverName.sin_port = htons(remotePort);
(void) memcpy(&serverName.sin_addr,
hostPtr->h_addr,
hostPtr->h_length);
status = connect(clientSocket,
(struct sockaddr*) &serverName,
sizeof(serverName));
if (-1 == status)
{
perror("connect()");
exit(1);
}
/*
* Client application specific code goes here
*
* e.g. receive messages from server, respond,
* etc. */
while (0 < (status = read(clientSocket,
buffer, sizeof(buffer) - 1)))
{
printf("%d: %s", status, buffer);
}
if (-1 == status)
{
perror("read()");
}
close(clientSocket);
return 0;
}
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