This section provides DEC C socket communications programming examples.
Example A-1 is an example of a TCP/IP Server.
/*====================================================================
*
* Copyright (C) 1989 by
* Digital Equipment Corporation, Maynard, Mass.
*
* This software is furnished under a license and may be used and copied
* only in accordance with the terms of such license and with the
* inclusion of the above copyright notice. This software or any other
* copies thereof may not be provided or otherwise made available to any
* other person. No title to and ownership of the software is hereby
* transferred.
*
* The information in this software is subject to change without notice
* and should not be construed as a commitment by Digital Equipment
* Corporation.
*
* Digital assumes no responsibility for the use or reliability of its
* software on equipment that is not supplied by Digital.
*
*
*
* FACILITY:
* INSTALL
*
*
* ABSTRACT:
* This is an example of a TCP/IP server using the IPC
* socket interface.
*
*
* ENVIRONMENT:
* UCX V1.2 or higher, VMS V5.2 or higher
*
* This example is portable to ULTRIX. The include
* files are conditionally defined for both systems, and
* "perror" is used for error reporting.
*
* To link in DEC C on OpenVMS Systems, you must have the following
* entries in your .opt file:
* sys$library:ucx$ipc.olb/lib
* sys$share:vaxcrtl.exe/share
*
* AUTHORS:
* UCX Developer
*
* CREATION DATE: May 23, 1989
*
* MODIFICATION HISTORY:
*
*/
/*
*
* INCLUDE FILES
*
*/
#ifdef __VMS
#include <errno.h>
#include <stdio.h>
#include <socket.h>
#include <in.h>
#include <netdb.h> /* Change hostent to comply with BSD 4.3. */
#include <inet.h>
#include <ucx$inetdef.h> /* INET symbol definitions. */
#else
#include <errno.h>
#include <sys/types.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/uio.h>
#endif
/*
* Functional Description
*
* This example creates a socket of type SOCK_STREAM (TCP),
* binds and listens on the socket, receives a message,
* and closes the connection.
* Error messages are printed to the screen.
*
* IPC calls used:
* accept
* bind
* close
* gethostbyname
* listen
* recv
* shutdown
* socket
*
*
* Formal Parameters
* The server program expects one parameter:
* portnumber ... port number where it will listen
*
*
* Routine Value
*
* Status
*/
/*--------------------------------------------------------------------*/
main(argc,argv)
int argc;
char **argv;
{
int sock_2, sock_3; /* sockets */
static char message[BUFSIZ];
static struct sockaddr_in sock2_name; /* Address struct for socket2.*/
static struct sockaddr_in retsock2_name; /* Address struct for socket2.*/
struct hostent hostentstruct; /* Storage for hostent data. */
struct hostent *hostentptr; /* Pointer to hostent data. */
static char hostname[256]; /* Name of local host. */
int flag;
int retval; /* Helpful for debugging. */
int namelength;
/*
* Check input parameters.
*/
if (argc != 2 )
{
printf("Usage: server portnumber.\n");
exit();
}
/*
* Open socket 2: AF_INET, SOCK_STREAM.
*/
if ((sock_2 = socket (AF_INET, SOCK_STREAM, 0)) == -1)
{
perror( "socket");
exit();
}
/*
* Get the host local name.
*/
retval = gethostname(hostname,sizeof hostname);
if (retval)
{
perror ("gethostname");
cleanup (1, sock_2, 0);
}
/*
* Get pointer to network data structure for socket 2.
*/
if ((hostentptr = gethostbyname (hostname)) == NULL)
{
perror( "gethostbyname");
cleanup(1, sock_2, 0);
}
/*
* Copy hostent data to safe storage.
*/
hostentstruct = *hostentptr;
/*
* Fill in the name & address structure for socket 2.
*/
sock2_name.sin_family = hostentstruct.h_addrtype;
sock2_name.sin_port = htons(atoi(argv[1]));
sock2_name.sin_addr = * ((struct in_addr *) hostentstruct.h_addr);
/*
* Bind name to socket 2.
*/
retval = bind (sock_2, &sock2_name, sizeof sock2_name);
if (retval)
{
perror("bind");
cleanup(1, sock_2, 0);
}
/*
* Listen on socket 2 for connections.
*/
retval = listen (sock_2, 5);
if (retval)
{
perror("listen");
cleanup(1, sock_2, 0);
}
/*
* Accept connection from socket 2:
* accepted connection will be on socket 3.
*/
namelength = sizeof (sock2_name);
sock_3 = accept (sock_2, &sock2_name, &namelength);
if (sock_3 == -1)
{
perror ("accept");
cleanup( 2, sock_2, sock_3);
}
/*
* Receive message from socket 1.
*/
flag = 0; /* maybe 0 or MSG_OOB or MSG_PEEK */
retval = recv(sock_3, message ,sizeof (message), flag);
if (retval == -1)
{
perror ("receive");
cleanup( 2, sock_2, sock_3);
}
else
printf (" %s\n", message);
/*
* Call cleanup to shutdown and close sockets.
*/
cleanup(2, sock_2, sock_3);
} /* end main */
/*-----------------------------------------------------------*/
cleanup(how_many, sock1, sock2)
int how_many;
int sock1, sock2;
{
int retval;
/*
* Shutdown and close sock1 completely.
*/
retval = shutdown(sock1,2);
if (retval == -1)
perror ("shutdown");
retval = close (sock1);
if (retval)
perror ("close");
/*
* If given, shutdown and close sock2.
*/
if (how_many == 2)
{
retval = shutdown(sock2,2);
if (retval == -1)
perror ("shutdown");
retval = close (sock2);
if (retval)
perror ("close");
}
exit();
} /* end cleanup*/
Example A-2 is an example of a TCP/IP Client.
/*====================================================================
*
* Copyright (C) 1989 by
* Digital Equipment Corporation, Maynard, Mass.
*
* This software is furnished under a license and may be used and copied
* only in accordance with the terms of such license and with the
* inclusion of the above copyright notice. This software or any other
* copies thereof may not be provided or otherwise made available to any
* other person. No title to and ownership of the software is hereby
* transferred.
*
* The information in this software is subject to change without notice
* and should not be construed as a commitment by Digital Equipment
* Corporation.
*
* Digital assumes no responsibility for the use or reliability of its
* software on equipment that is not supplied by Digital.
*
*
*
* FACILITY:
* INSTALL
*
*
* ABSTRACT:
* This is an example of a TCP/IP client using the IPC
* socket interface.
*
*
* ENVIRONMENT:
* UCX V1.2 or higher, VMS V5.2 or higher
*
* This example is portable to ULTRIX. The include
* files are conditionally defined for both systems, and
* "perror" is used for error reporting.
*
* To link in DEC C on OpenVMS Systems, you must have the following
* entries in your .opt file:
* sys$library:ucx$ipc.olb/lib
* sys$share:vaxcrtl.exe/share
*
* AUTHORS:
* UCX Developer
*
* CREATION DATE: May 23, 1989
*
* MODIFICATION HISTORY:
*
*/
/*
*
* INCLUDE FILES
*
*/
#ifdef __VMS
#include <errno.h>
#include <stdio.h>
#include <socket.h>
#include <in.h>
#include <netdb.h> /* Change hostent to comply with BSD 4.3. */
#include <inet.h>
#include <ucx$inetdef.h> /* INET symbol definitions. */
#else
#include <errno.h>
#include <sys/types.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/uio.h>
#endif
/*
*
* MACRO DEFINITIONS
*
*/
#ifndef vms
#define TRUE 1
#define FALSE 0
#endif
/*
* Functional Description
*
* This example creates a socket of type SOCK_STREAM (TCP),
* initiates a connection to the remote host, sends
* a message to the remote host, and closes the connection.
* Error messages are printed to the screen.
*
* IPC calls used:
* close
* connect
* gethostbyname
* send
* shutdown
* socket
*
*
* Formal Parameters
* The client program expects two parameters:
* hostname ... name of remote host
* portnumber ... port where remote host(server) is listening
*
*
* Routine Value
*
* Status
*/
/*--------------------------------------------------------------------*/
main(argc,argv)
int argc;
char **argv;
{
int sock_1; /* socket */
static char message[] = "Hi there.";
static struct sockaddr_in sock2_name; /* Address struct for socket2.*/
struct hostent hostentstruct; /* Storage for hostent data. */
struct hostent *hostentptr; /* Pointer to hostent data. */
static char hostname[256]; /* Name of local host. */
int flag;
int retval; /* Helpful for debugging. */
int shut = FALSE; /* Flag to cleanup. */
/*
* Check input parameters.
*/
if (argc != 3 )
{
printf("Usage: client hostname portnumber.\n");
exit();
}
/*
* Open socket 1: AF_INET, SOCK_STREAM.
*/
if ((sock_1 = socket (AF_INET, SOCK_STREAM, 0)) == -1)
{
perror( "socket");
exit();
}
/*
*Get pointer to network data structure for socket 2 (remote host).
*/
if ((hostentptr = gethostbyname (argv[1])) == NULL)
{
perror( "gethostbyname");
cleanup(shut, sock_1);
}
/*
* Copy hostent data to safe storage.
*/
hostentstruct = *hostentptr;
/*
* Fill in the name & address structure for socket 2.
*/
sock2_name.sin_family = hostentstruct.h_addrtype;
sock2_name.sin_port = htons(atoi(argv[2]));
sock2_name.sin_addr = * ((struct in_addr *) hostentstruct.h_addr);
/*
* Connect socket 1 to sock2_name.
*/
retval = connect(sock_1, &sock2_name, sizeof (sock2_name));
if (retval)
{
perror("connect");
cleanup(shut, sock_1);
}
/*
* Send message to socket 2.
*/
flag = 0; /* maybe 0 or MSG_OOB */
retval = send(sock_1, message ,sizeof (message), flag);
if (retval < 0)
{
perror ("send");
shut = TRUE;
}
/*
* Call cleanup to shutdown and close socket.
*/
cleanup(shut, sock_1);
} /* end main */
/*-----------------------------------------------------------*/
cleanup(shut, socket)
int shut;
int socket;
{
int retval;
/*
* Shutdown socket completely -- only if it was connected.
*/
if (shut) {
retval = shutdown(socket,2);
if (retval == -1)
perror ("shutdown");
}
/*
* Close socket.
*/
retval = close (socket);
if (retval)
perror ("close");
exit();
} /* end main */
Example A-3 is an example of a UDP/IP Server.
/*====================================================================
*
* Copyright (C) 1989 by
* Digital Equipment Corporation, Maynard, Mass.
*
* This software is furnished under a license and may be used and copied
* only in accordance with the terms of such license and with the
* inclusion of the above copyright notice. This software or any other
* copies thereof may not be provided or otherwise made available to any
* other person. No title to and ownership of the software is hereby
* transferred.
*
* The information in this software is subject to change without notice
* and should not be construed as a commitment by Digital Equipment
* Corporation.
*
* Digital assumes no responsibility for the use or reliability of its
* software on equipment that is not supplied by Digital.
*
*
*
* FACILITY:
* INSTALL
*
*
* ABSTRACT:
* This is an example of a UDP/IP server using the IPC
* socket interface.
*
*
* ENVIRONMENT:
* UCX V1.2 or higher, VMS V5.2 or higher
*
* This example is portable to ULTRIX. The include
* files are conditionally defined for both systems, and
* "perror" is used for error reporting.
*
* To link in DEC C on OpenVMS Systems, you must have the following
* entries in your .opt file:
* sys$library:ucx$ipc.olb/lib
* sys$share:vaxcrtl.exe/share
*
* AUTHORS:
* UCX Developer
*
* CREATION DATE: May 23, 1989
*
* MODIFICATION HISTORY:
*
*/
/*
*
* INCLUDE FILES
*
*/
#ifdef __VMS
#include <errno.h>
#include <stdio.h>
#include <socket.h> /* timeval declared here. */
#include <in.h>
#include <netdb.h> /* Change hostent to comply with BSD 4.3. */
#include <inet.h>
#include <ucx$inetdef.h> /* INET symbol definitions. */
#else
#include <errno.h>
#include <sys/types.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/uio.h>
#include <time.h> /* timeval declared here. */
#endif
/*
* Functional Description
*
* This example creates a socket of type SOCK_DGRAM (UDP), binds
* it, and selects to receive a message on the socket.
* Error messages are printed to the screen.
*
* IPC calls used:
* bind
* close
* gethostbyname
* recvfrom
* select
* shutdown
* socket
*
*
* Formal Parameters
* The server program expects one parameter:
* portnumber ... port where it is listening
*
*
* Routine Value
*
* Status
*/
/*--------------------------------------------------------------------*/
main(argc, argv)
int argc;
char **argv;
{
unsigned long rmask,wmask,emask;
int sock_2; /* Socket2 descriptor. */
int buflen,fromlen;
char recvbuf[BUFSIZ];
static struct sockaddr_in sock1_name; /* Address struct for socket1.*/
static struct sockaddr_in sock2_name; /* Address struct for socket2.*/
int namelength;
struct hostent hostentstruct; /* Storage for hostent data. */
struct hostent *hostentptr; /* Pointer to hostent data. */
static char hostname[256]; /* Name of local host. */
int retval;
int flag;
struct timeval timeout;
/*
* Check input parameters.
*/
if (argc != 2 )
{
printf("Usage: server portnumber.\n");
exit();
}
/*
* Open socket 2: AF_INET, SOCK_DGRAM.
*/
if ((sock_2 = socket (AF_INET, SOCK_DGRAM, 0)) == -1)
{
perror( "socket");
exit();
}
/*
* Get the local host name.
*/
retval = gethostname(hostname,sizeof hostname);
if (retval)
{
perror ("gethostname");
cleanup(sock_2);
}
/*
* Get pointer to network data structure for local host.
*/
if ((hostentptr = gethostbyname (hostname)) == NULL)
{
perror( "gethostbyname");
cleanup(sock_2);
}
/*
* Copy hostent data to safe storage.
*/
hostentstruct = *hostentptr;
/*
* Fill in the address structure for socket 2.
*/
sock2_name.sin_family = hostentstruct.h_addrtype;
sock2_name.sin_port = htons(atoi(argv[1]));
sock2_name.sin_addr = * ((struct in_addr *) hostentstruct.h_addr);
/*
* Bind name to socket 2.
*/
retval = bind (sock_2, &sock2_name, sizeof sock2_name);
if (retval)
{
perror("bind");
cleanup(sock_2);
}
/*
* Select socket to receive message.
*/
emask = wmask = 0;
rmask = (1<<sock_2); /* set read mask */
timeout.tv_sec = 30;
timeout.tv_usec = 0;
retval = select(32,&rmask,&wmask,&emask, &timeout);
switch (retval)
{
case -1:
{
perror("select");
cleanup(sock_2);
}
case 0:
{
printf("Select timed out with status 0.\n");
cleanup(sock_2);
}
default:
if ((rmask & (1<<sock_2)) == 0)
{
printf("Select not reading on sock_2.\n");
cleanup(sock_2);
}
} /*switch*/
/*
* Recvfrom buffer - from sock1 on sock2.
*/
buflen = sizeof(recvbuf);
fromlen = sizeof(sock1_name);
flag = 0; /* flag may be MSG_OOB and/or MSG_PEEK */
retval = recvfrom(sock_2, recvbuf, buflen, flag, &sock1_name, &fromlen);
if (retval == -1)
perror("recvfrom");
else
printf (" %s\n", recvbuf);
/*
* Call cleanup to shut down and close socket.
*/
cleanup(sock_2);
} /* end main */
/*-----------------------------------------------------------*/
cleanup(socket)
int socket;
{
int retval;
/*
* Shut down socket completely.
*/
retval = shutdown(socket,2);
if (retval == -1)
perror ("shutdown");
/*
* Close socket.
*/
retval = close (socket);
if (retval)
perror ("close");
exit();
} /* end cleanup */
Example A-4 is an example of a UDP/IP client.
/*====================================================================
*
* Copyright (C) 1989 by
* Digital Equipment Corporation, Maynard, Mass.
*
* This software is furnished under a license and may be used and copied
* only in accordance with the terms of such license and with the
* inclusion of the above copyright notice. This software or any other
* copies thereof may not be provided or otherwise made available to any
* other person. No title to and ownership of the software is hereby
* transferred.
*
* The information in this software is subject to change without notice
* and should not be construed as a commitment by Digital Equipment
* Corporation.
*
* Digital assumes no responsibility for the use or reliability of its
* software on equipment that is not supplied by Digital.
*
*
*
* FACILITY:
* INSTALL
*
*
* ABSTRACT:
* This is an example of a UDP/IP client using the IPC
* socket interface.
*
*
* ENVIRONMENT:
* UCX V1.2 or higher, VMS V5.2 or higher
*
* This example is portable to ULTRIX. The include
* files are conditionally defined for both systems, and
* "perror" is used for error reporting.
*
* To link in DEC C on OpenVMS Systems, you must have the following
* entries in your .opt file:
* sys$library:ucx$ipc.olb/lib
* sys$share:vaxcrtl.exe/share
*
* AUTHORS:
* UCX Developer
*
* CREATION DATE: May 23, 1989
*
* MODIFICATION HISTORY:
*
*/
/*
*
* INCLUDE FILES
*
*/
#ifdef __VMS
#include <errno.h>
#include <stdio.h>
#include <socket.h>
#include <in.h>
#include <netdb.h> /* Change hostent to comply with BSD 4.3. */
#include <inet.h>
#include <ucx$inetdef.h> /* INET symbol definitions. */
#else
#include <errno.h>
#include <sys/types.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <sys/uio.h>
#endif
/*
* Functional Description
*
* This example creates a socket of type SOCK_DGRAM (UDP),
* binds it, and sends a message to the given host and port number.
* Error messages are printed to the screen.
*
* IPC calls used:
* bind
* close
* gethostbyname
* sendto
* shutdown
* socket
*
* Formal Parameters
* The client program expects two parameters:
* hostname ... name of remote host
* portnumber ... port where remote host(server) is listening
*
*
* Routine Value
*
* Status
*/
/*--------------------------------------------------------------------*/
main(argc, argv)
int argc;
char **argv;
{
int sock_1; /* Socket 1 descriptor. */
int sendlen, tolen;
static char sendbuf[] = "Hi there.";
static struct sockaddr_in sock2_name; /* Address struct for socket2.*/
int namelength;
struct hostent hostentstruct; /* Storage for hostent data. */
struct hostent *hostentptr; /* Pointer to hostent data. */
static char hostname[256]; /* Name of local host. */
int flag;
int retval;
/*
* Check input parameters.
*/
if (argc != 3 )
{
printf("Usage: client hostname portnumber.\n");
exit();
}
/*
* Open socket 1: AF_INET, SOCK_DGRAM.
*/
if ((sock_1 = socket (AF_INET, SOCK_DGRAM, 0)) == -1)
{
perror( "socket");
exit();
}
/*
*Get pointer to network data structure for given host.
*/
if ((hostentptr = gethostbyname (argv[1])) == NULL)
{
perror( "gethostbyname");
cleanup(sock_1);
}
/*
* Copy hostent data to safe storage.
*/
hostentstruct = *hostentptr;
/*
* Fill in the address structure for socket 2 (to receive message).
*/
sock2_name.sin_family = hostentstruct.h_addrtype;
sock2_name.sin_port = htons(atoi(argv[2]));
sock2_name.sin_addr = * ((struct in_addr *) hostentstruct.h_addr);
/*
* Initialize send block.
*/
sendlen = sizeof sendbuf;
tolen = sizeof sock2_name;
flag = 0; /* flag may be MSG_OOB */
/*
* Send message from socket 1 to socket 2.
*/
retval = sendto(sock_1, sendbuf, sendlen, flag, &sock2_name,tolen);
if (retval == -1)
{
perror ( "sendto");
cleanup(sock_1);
}
/*
* Call cleanup to shut down and close socket.
*/
cleanup(sock_1);
} /* end main */
/*-----------------------------------------------------------*/
cleanup(socket)
int socket;
{
int retval;
/*
* Shut down socket completely.
*/
retval = shutdown(socket,2);
if (retval == -1)
perror ("shutdown");
/*
* Close socket.
*/
retval = close (socket);
if (retval)
perror ("close");
exit();
} /* end cleanup */