C / C++ / MFC

31-Mar-06 4:39

I finally finished my project. So I thought I would test it on a neighbours computers, just in case. And it doesn't work :'(

I have narrowed the problem down to the importing and initialising of an activeX dll. But I can't find out why it works on my machine and not on another (with identical configuration).

Here is the code:

_clsXLPtr xls;

try {
    CoInitialize(NULL);

    xls.CreateInstance(__uuidof(clsXL)); // failing
    xls->Visible(&vis);

The CreateInstance call is failing, but why?

Wes Aday31-Mar-06 4:46

Wes Aday

31-Mar-06 4:46

If the DLL registered on your neighbors computer?

Why is common sense not common?

Never argue with an idiot. They will drag you down to their level where they are an expert.

David Crow31-Mar-06 4:49

31-Mar-06 4:49

waldermort wrote:
xls.CreateInstance(__uuidof(clsXL)); // failing

Had you bothered to check the return value of CreateInstance(), you would have likely seen it was -2147221164, which indicates a class has not yet been registered. You'll need to use regsvr32 for this.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Waldermort31-Mar-06 4:56

31-Mar-06 4:56

Thanks for the quick replies. Could you possibly explain why this works on my machine and not on others?

David Crow31-Mar-06 5:06

31-Mar-06 5:06

waldermort wrote:
Could you possibly explain why this works on my machine and not on others?

Because of lack of registration.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Waldermort31-Mar-06 5:26

31-Mar-06 5:26

Now I'm getting error's when trying to register. "ExCom.dll was loaded, but the DllInstall entry point was not found.".

David Crow31-Mar-06 5:30

31-Mar-06 5:30

Which indicates DllInstall() does not exist or has not been (properly) exported.

See here for more.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Waldermort31-Mar-06 5:58

31-Mar-06 5:58

WinExec("regsvr32 ExCom.dll",SW_SHOW);

"DllRegisterServer in ExCom.dll Succeeded".

Yet CreateInstance() is still failing on the other machine.

David Crow31-Mar-06 6:05

31-Mar-06 6:05

waldermort wrote:
Yet CreateInstance() is still failing on the other machine.

What is it returning?

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Waldermort31-Mar-06 6:17

31-Mar-06 6:17

-2147221164.

#import "ExCom.dll"  no_namespace

WinExec("regsvr32 /s ExCom.dll",SW_SHOW);
	
try {
    CoInitialize(NULL);

    long foo = xls.CreateInstance(__uuidof(clsXL));
    char *val = new char [100];
    ltoa(foo,val,10);
    MessageBox(NULL,val,0,0);
    delete val;
		
    xls->Visible(&vis);
} catch(_com_error &e) {
    data.error = e.Description();
    MessageBox(NULL,_com_util::ConvertBSTRToString(data.error),0,0);
}

I'm sorry about this, and I thank you for your kind replies.

Solved

Waldermort31-Mar-06 6:36

31-Mar-06 6:36

I don't know how or why but it's seems to be working now. I deleted every file including the dll's and libs apart from the source files and completely rebuilt everything. And hey presto it works. I have a feeling that choosing 'clean' and 'rebuild all' from the menu wasn't producing the same result.

Maybe it's time I got a newer version of my compiler.

Thanks for your help.

Re: Solved

David Crow31-Mar-06 6:59

31-Mar-06 6:59

I suspect it was that call to WinExec(). You should be able to turn the error on and off by simply unregistering the DLL (from a command prompt not WinExec()).

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

David Crow31-Mar-06 6:55

31-Mar-06 6:55

waldermort wrote:

WinExec("regsvr32 ExCom.dll",SW_SHOW);

Why are you doing this programmatically? Do it once from the command prompt.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

Waldermort31-Mar-06 7:11

31-Mar-06 7:11

This would go into the installer.

I was sending the file to my neighbour so he can test it for me, therefore I wanted to make it as simple as possible for him.

David Crow31-Mar-06 7:17

How to encrpyt a file and decrpyt on the fly

31-Mar-06 7:17

But it is potentially a timing problem where your program is trying to use the DLL before it has been registered. By registering at a command prompt, or through an actual install-type program, you've eliminated this possibility.

"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain

"There is no death, only a change of worlds." - Native American Proverb

beko31-Mar-06 3:32

beko

31-Mar-06 3:32

Hello All,

I have a program which uses a XML file for initialisation of the program. Now i have to make that XML file scrambled or decoded in order to give to the end user. (it was not required in the beginning of the project)

How can i encrypt a file(since i need to modify couple of other files not just an XML file) and decrpyt on the memory without creating a temporary decrypted file?

Actually i can encrypt the file but i don't know how to decrypt the file on the memory into a text-based XML file and then use it as i used to do.

can Memory File Mapping be used for this? (i just heard it but never used)

or is there any other simple way?

I am currently using TinyXML and standard C++ streams for data reading.

Thanks

Re: How to encrpyt a file and decrpyt on the fly

David Crow31-Mar-06 3:57