Interprocess Communication

[John Norman]

I'm trying to pas data back and forth between a vb app, and a c++ app.
I have tried several methods:

Through a dll (written in C++), doesn't work because each app has it's
own instances of the variables declared in the dll. Is there a way to
force one instance?

Windows messaging - I could only get it working by broadcast, then it
calls Internet Explorer, and wierd stuff happens.

FileMapping - I'm working on this method now, having trouble with some
of the api's in C.

Can anyone offer any suggestions?

Thanks in Advance

John Norman

[Stephane Richard]

Through a dll (written in C++), doesn't work because each app has it's
own instances of the variables declared in the dll. Is there a way to
force one instance?

To this....the API would let you search for an existing instance of the
object and use that one instead of creating a new instance

--
Stéphane Richard
Senior Software and Technology Supervisor
http://www.totalweb-inc.com
For all your hosting and related needs
"John Norman" <re***@throughnewsgrp.com> wrote in message
news:je********************************@4ax.com...

I'm trying to pas data back and forth between a vb app, and a c++ app.
I have tried several methods:

Through a dll (written in C++), doesn't work because each app has it's
own instances of the variables declared in the dll. Is there a way to
force one instance?

Windows messaging - I could only get it working by broadcast, then it
calls Internet Explorer, and wierd stuff happens.

FileMapping - I'm working on this method now, having trouble with some
of the api's in C.

Can anyone offer any suggestions?

Thanks in Advance

John Norman

[J French]

Ok,
since you have full control of the CPP DLL and the VB App,
- this is how I do it

1) RegisterWindowsMessage using a unique string ID
- that gives you a 'unique' Windows Message Number
2) Broadcast on this number, and make all recipients reply
- sending back their hWnds
3) SendMessage using WM_COPYDATA to then now known hWnd(s)

If you can understand Delphi / Pascal then I could post you an example
that 'chats' - or a DLL that encapsulates it

On Mon, 07 Jul 2003 17:40:54 -0700, John Norman
<re***@throughnewsgrp.com> wrote:

I'm trying to pas data back and forth between a vb app, and a c++ app.
I have tried several methods:

Through a dll (written in C++), doesn't work because each app has it's
own instances of the variables declared in the dll. Is there a way to
force one instance?

Windows messaging - I could only get it working by broadcast, then it
calls Internet Explorer, and wierd stuff happens.

FileMapping - I'm working on this method now, having trouble with some
of the api's in C.

Can anyone offer any suggestions?

Thanks in Advance

John Norman

[Asperamanca]

John Norman <re***@throughnewsgrp.com> wrote in message news:<je********************************@4ax.com>. ..

I'm trying to pas data back and forth between a vb app, and a c++ app.
I have tried several methods:

Through a dll (written in C++), doesn't work because each app has it's
own instances of the variables declared in the dll. Is there a way to
force one instance?

Windows messaging - I could only get it working by broadcast, then it
calls Internet Explorer, and wierd stuff happens.

FileMapping - I'm working on this method now, having trouble with some
of the api's in C.

Can anyone offer any suggestions?

Thanks in Advance

John Norman

A pretty complete documentation on how to pass data between processes
can be found at the following URL:
http://msdn.microsoft.com/library/de...unications.asp

Robert

[John Norman]

Stephane,
Do you know which api's handle this?

Thanks
John

On Tue, 08 Jul 2003 00:57:08 GMT, "Stephane Richard"
<st**************@verizon.net> wrote:

Through a dll (written in C++), doesn't work because each app has it's
own instances of the variables declared in the dll. Is there a way to
force one instance?

To this....the API would let you search for an existing instance of the
object and use that one instead of creating a new instance

[J French]

This is a complete red herring

DLLs leech of the Data Area of their parent EXEs
- although they all share the same Code Area, they all have different
Data Areas - if they belong to different EXEs

There is just one curious exception, which seems to be memory mapped
files - I still have not got to the bottom of that.

Passing data between VB Apps (not VB to CPP) is pretty easy, you
simply use an AX EXE
- which _does_ have its own Data Area
- and hence that is 'shared' between anything using the EXE
(providing the instancing of the AX EXE has been correctly set up)

This is probably of little use for Inter-Language and App
communication - but nifty for VB to VB

On Tue, 08 Jul 2003 05:32:14 -0700, John Norman
<re***@throughnewsgrp.com> wrote:

Stephane,
Do you know which api's handle this?

Thanks
John

On Tue, 08 Jul 2003 00:57:08 GMT, "Stephane Richard"
<st**************@verizon.net> wrote:

Through a dll (written in C++), doesn't work because each app has it's
own instances of the variables declared in the dll. Is there a way to
force one instance?

To this....the API would let you search for an existing instance of the
object and use that one instead of creating a new instance