examples/PIPS/HelloWorldExample/src/helloworldexeexample/helloworldexeexample.c

// helloworldexeexample.c
//
// Copyright (c) 2007-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
//


/* This example is a simple PIPS STDEXE application. It loads the DLL and calls its exported function. 
The application implements the dynamic lookup by name mechanism of the exported function using the libdl APIs.
*/

// Include files.
#include <stdio.h>
#include <dlfcn.h>
#include <stdlib.h>

void PressAKey()
        {
        fflush(stdout);
        getchar();
        }
int DisplayErrorMessage()
        {
        // Obtain the last error occurred using the libdl API, dlerror().
        const char *q = dlerror();
        
        // Prints the error message.
        printf("%s",q);
        PressAKey();
                
        // returns the failure code.
        return EXIT_FAILURE;
        }

int main()
{
        int result;
        
        // Handle to load the dynamic library.
        void* handleToDll;
        
        typedef void (*PrintHelloWorldFunction)(void);
        PrintHelloWorldFunction PrintHelloWorld;
        
        // Contains name of the DLL file.
        char dllFileName[] = "helloworlddllexample.dll";

        handleToDll = dlopen(dllFileName, RTLD_LAZY);
        
        // Check the descriptor value.If it is null, the error message is printed.
        if (!handleToDll)
                {
                DisplayErrorMessage();
                }
        
        // Print the message to start the example application.
        printf(" Press enter key to step through the example application\n");
        PressAKey();

        PrintHelloWorld = (PrintHelloWorldFunction)dlsym(handleToDll, "PrintHelloWorld");   
        
        // Check the symbol address value. If this is null, the error message is printed.
        if(!PrintHelloWorld)
                {
                DisplayErrorMessage();
                }

        // Call the loaded DLL's exported function.
        PrintHelloWorld();

        result= dlclose(handleToDll);
        
        // Check the return value. If this is -1, the error message is printed.
        if(result == -1)
                {
                DisplayErrorMessage();
                }
        
        // Print the message to exit from the example application.
        printf(" Press enter key to exit from the example application");
        PressAKey();
        
        // returns the success code.
        return EXIT_SUCCESS;
}

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