how to transfer data between VC++ projects.

[avivhal]

how can i transfer variable from one project to another?
for example should i write in one project:
extern int x;
x=1;

wnd in another i would like to write:
int y;
y=x;


i dont want to use assembly or writing to files but just the extern system with functions or vars.
Thanks, Aviv.

 

[TGM]

Hi

Well you got in fact several solutions, depending on the amount of data to exchange, the frequency and the direction of exchange.

You can consider :
- the Clipboard: potential problem if user hit Ctrl-C or X
- DDE: old-fashion but still useable
- TCP/IP¨: you can find powerful class on the Web
- Memory mapped files
- Shared memory Segments

Memory mapped files are not actual files and could be used to exchange large amount of data between apps. You'll find a class called CSharedMemory created by Jeff Prosise in

http://www.microsoft.com/MSJ/1198/wicked1198.htm

The last one, Shared memory segments, is very easy.

Simply declare this on the top of your implementation file:

#pragma data_seg( ".Shared&quot
BOOL bData = FALSE;
#pragma data_seg()
#pragma comment(linker, "section:.Shared,RWS&quot

The name of the shared segment can be what fits your need but must start with a period. You must also init the variables inside the #pragma. The type of data is what you need.

In your code, you can use bData as a normal variable.

Note that there is no synchronisation, so both can write at the same time in the same variable.

HTH

Thierry
EMail: Thierry.Marneffe@swing.be