Purpose
Creates a Transmission Control Protocol/Internet Protocol (TCP/IP) client transport handle.
Library
C Library (libc.a)
Syntax
CLIENT *clnttcp_create (addr, prognum, versnum, sockp, sendsz, recvsz)
struct sockaddr_in * addr;
u_long prognum, versnum;
int * sockp;
u_int sendsz, recvsz;
Description
The clnttcp_create subroutine creates a Remote Procedure Call (RPC) client transport handle for a remote program. This client uses TCP/IP as the transport to pass messages to the service.
The TCP/IP remote procedure calls use buffered input/output (I/O). Users can set the size of the send and receive buffers with the sendsz and recvsz parameters. If the size of either buffer is set to a value of 0, the clnttcp_create subroutine picks suitable default values.
Parameters
| Item | Description |
|---|---|
| addr | Points to the Internet address of the remote program. If the port number for this Internet address (addr->sin_port) is a value of 0, then the addr parameter is set to the actual port on which the remote program is listening. The client making the remote procedure call consults the remote portmap daemon to obtain the port information. |
| prognum | Specifies the program number of the remote program. |
| versnum | Specifies the version number of the remote program. |
| sockp | Specifies a pointer to a socket. If the value of the sockp parameter is RPC_ANYSOCK, the clnttcp_create subroutine opens a new socket and sets the sockp pointer to the new socket. |
| sendsz | Sets the size of the send buffer. |
| recvsz | Sets the size of the receive buffer. |
Return Values
Upon successful completion, this routine returns a valid TCP/IP client handle. If unsuccessful, it returns a value of null.
Purpose
Creates a Transmission Control Protocol/Internet Protocol (TCP/IP) client transport handle.
Library
Network Services Library (libnsl.a)
Syntax
#include <rpc/rpc.h>CLIENT *clnttcp_create (addr, prognum, versnum, fdp, sendsz, recvsz)
struct sockaddr_in *addr;
rpcprog_t prognum;
rpcvers_t versnum;
int *fdp;
uint_t sendsz, recvsz;Description
The clnttcp_create subroutine creates a Remote Procedure Call (RPC) client transport handle for a remote program. This client uses TCP/IP as the transport to pass messages to the service.
The TCP/IP remote procedure calls use buffered input/output (I/O). Users can set the size of the send and receive buffers with the sendsz and recvsz parameters. If the size of either buffer is set to a value of 0, the clnttcp_create subroutine picks suitable default values.
Parameters
| Item | Description |
|---|---|
| addr | Points to the Internet address of the remote program. If the port number for this Internet address (addr->sin_port) is a value of 0, then the addr parameter is set to the actual port on which the remote program is listening. The client making the remote procedure call consults the remote portmap daemon to obtain the port information. |
| prognum | Specifies the program number of the remote program. |
| versnum | Specifies the version number of the remote program. |
| fdp | Specifies a pointer to a socket. If the value of the fdp parameter is RPC_ANYSOCK, the clnttcp_create subroutine opens a new socket and sets the fdp pointer to the new socket. |
| sendsz | Sets the size of the send buffer. |
| recvsz | Sets the size of the receive buffer. |
Return Values
| Item | Description |
|---|---|
| a valid TCP/IP client handle | successful |
| a null value | unsuccessful |
Error Codes
| Item | Description |
|---|---|
| RPC_PROGNOTREGISTERED | The program is not registered. |
| RPC_SYSTEMERROR | The file descriptor is not valid. |
Examples
In the following example, the clnttcp_create subroutine creates and returns a TCP/IP client transport handle.
#include <rpc/rpc.h>
#include <stdio.h>
#define ADDRBUFSIZE 255
int main()
{
CLIENT *clnt;
rpcprog_t PROGNUM = 0x3fffffffL;
rpcvers_t PROGVER = 0x1L;
int fd;
uint_t sendsz=0, recvsz=0;
struct sockaddr_in addr;
char addrbuf[ADDRBUFSIZE];
struct netbuf svcaddr;
struct netconfig *nconf;
char host[255] ; /* The remote host name */
svcaddr.len = 0;
svcaddr.maxlen = ADDRBUFSIZE;
svcaddr.buf = addrbuf;
/* Get pointer to struct netconfig for tcp transport */
nconf = getnetconfigent("tcp");
if (nconf == (struct netconfig *) NULL) {
printf("getnetconfigent() failed\n");
exit(1);
}
/* Get the address of remote service */
if (!rpcb_getaddr(PROGNUM, PROGVER, nconf, &svcaddr, host)) {
printf("rpcb_getaddr() failed\n");
exit(1);
}
memcpy(&addr, svcaddr.buf, sizeof(struct sockaddr_in));
fd = ... /* Code to obtain open and bound file descriptor on tcp transport */
clnt = (CLIENT *) clnttcp_create(&addr, PROGNUM, PROGVER, &fd, sendsz, recvsz);
/*
* Make a call to clnt_call() subroutine
*/
/* Destroy the client handle in the end */
clnt_destroy(clnt);
return 0;
}