DCOM Client Source Code

Following is a listing of the client program. We will describe all the important parts of this code in the following sections.

// RemoteClient.cpp : Defines the entry point for the console application.

//

#include "stdafx.h" // added _WIN32_DCOM

#include // get "cout"

#include // get _com_error

#include // get time_t

// extract definitions from server project

#include "..\RemoteServer\RemoteServer.h"

#include "..\RemoteServer\RemoteServer_i.c"

// forward reference for status display method

void ShowStatus( HRESULT hr );

int main(int argc, char* argv[])

{

HRESULT hr; // COM error code

IGetInfo *pI; // pointer to interface

// Get the server name from user

char name[32];

cout << "Enter Server Name:" <<>

gets( name );

_bstr_t Server = name;

// remote server info

COSERVERINFO cs;

// Init structures to zero

memset(&cs, 0, sizeof(cs));

// Allocate the server name in the COSERVERINFO struct

cs.pwszName = Server;

// structure for CoCreateInstanceEx

MULTI_QI qi[1];

memset(qi, 0, sizeof(qi));

// initialize COM

hr = CoInitialize(0);

ShowStatus( hr );

// macro to check for success

if (SUCCEEDED(hr))

{

// set a low level of security

hr = CoInitializeSecurity(NULL, -1, NULL, NULL,

RPC_C_AUTHN_LEVEL_NONE,

RPC_C_IMP_LEVEL_IMPERSONATE,

NULL,

EOAC_NONE,

NULL);

// init security

ShowStatus( hr );

}

if (SUCCEEDED(hr))

{

// Fill the qi with a valid interface

qi[0].pIID = &IID_IGetInfo;

// get the interface pointer

hr = CoCreateInstanceEx(

CLSID_GetInfo, // clsid

NULL, // outer unknown

CLSCTX_SERVER, // server context

&cs, // server info

1, // size of qi

qi ); // MULTI_QI array

ShowStatus( hr );

}

if (SUCCEEDED(hr))

http://devcentral.iticentral.com/articles/DCOM/intro_DCOM/part3/default.php (3 of 11) [7/9/2001 2:53:00 PM]

DevCentral - Understanding DCOM - Part III

{

BSTR bsName; // Basic style string

// Extract the interface from the MULTI_QI strucure

pI = (IGetInfo*)qi[0].pItf;

// Call a method on the remote server

hr = pI->GetComputerName( &bsName );

ShowStatus( hr );

// Convert name to a printable string

_bstr_t bst( bsName );

cout << "Server Name :" <<>

// get time from remote computer

time_t tt;

hr = pI->GetTimeT(&tt );

ShowStatus( hr );

// display time_t as a string

cout << "Server Time :" <<>

// Release the interface

pI->Release();

}

// Close COM

CoUninitialize();

// Prompt user to continue

cout << "Press ENTER to continue" <<>

getchar();

return 0;

}

// Display detailed status information

void ShowStatus( HRESULT hr )

{

if (SUCCEEDED(hr))

{

cout << "OK" <<>

}

else

{

// construct a _com_error using the HRESULT

_com_error e(hr);

char temp[32];

// convert to hexidecimal string and display

sprintf( temp, "0x%x", hr );

cout << "Error : " <<>

// The hr as a decimal number

cout << "Decimal : " <<>

// show the 1st 16 bits (SCODE)

cout << "SCODE : " <<>

// Show facility code as a decimal number

cout << "Facility: " <<>

// Show the severity bit

cout << "Severity: " <<>

// Use the _com_error object to format a message string. This is

// Much easier then using ::FormatMessage

cout << "Message : " <<>

}

}