VC++ .NET 2002: Using native C++ DLLs in MC++ & Getting incomplete output

  • Thread starter Thread starter Scott Chang
  • Start date Start date
S

Scott Chang

Hi all,
I copied a set of VC++ version 6 source code of
the 'cppdll'(2 projects) from a website and put the
cppdll.cpp, cppdll.def, cpp.h, (as the 1st project) and
test.cpp (as the 2nd project) into my Microsoft VC++ .NET
2002 - Windows XP Pro PC:
//----cppdll.cpp----
#include "cppdll.h"

//prevent function name from being mangled
extern "C"
int cube(int num) {
return num * num * num;
}
//-----cppdll.def----
EXPORTS
cube
//-----cpp.h------
/*
this header is not required for this dll
to compile; but is required for the app
that will use this dll
*/

#ifndef CPPDLL_H
#define CPPDLL_H

//computes the square of the number
//prevent the function name from being mangled
extern "C"
int cube(int num);

#endif //CPPDLL_H
//------test.cpp------
#include <iostream>

#include "cppdll.h"

using namespace std;

int main() {
int num;

cout << "enter any number: ";
cin >> num;

cout << "cube of number is "
<< cube(num) << endl;

return 0;
}
===============================================
I did 'Build' successfully, clicked '! Start without
debugging' and the console had 'enter any number'
appeared. I typed in a number on the console and
pressed 'Enter' key and the console screen just
vanished!!!??? I do not know what it is wrong with my
program. Please help and tell me (1) what I should change
in the 'Configuration Properties' for each of the
cppdll.cpp, cppdll.def, cppdll.h and test.cpp files, and
(2) whether it is possible to use the native C++ input to
get the cube of the input number in the MC++ framework by
using a native C++ DLL.
Thanks in advance,
Scott Chang
 
Scott,

The console window disappears when your application finishes. To keep
your application from finishing, add the following lines to the end of
the main function (before "return 0;"):

string s;
cin >> s;

This will cause the application to wait until after you have entered
some text.

Good luck!

Bart Jacobs
 
Thanks, Bart.

I added the two statements to my test.cpp as you said.
I did 'Build' on the new test.cpp and I got the following
error:
c:\Documents and Settings\Scott H. Chang\My
Documents\Visual Studio Projects\cppdll\test\test.cpp
(17): error C2679: binary '>>' : no operator found which
takes a right-hand operand of type 'std::string' (or
there is no acceptable conversion)

I do not know what to do next to correct this error.
Please help and advise again.

Thanks,
Scott Chang
 
I'm sorry for that. Instead of what I suggested before, try the following:

char buffer[200];
fgets(buffer, 200, stdin);

Also add the following to the start of the file:

#include <stdio.h>

Happy coding!

Bart Jacobs
 
Thanks, Bart.

I followed your instructions and added your new 3 lines
of code to my test.cpp. Then I did 'Build' on the new
test.cpp. Two strange happened after I did 'Build':
1) If I clicked '! Start without Debug' or 'Start' under
the Debug menu, I got the following dialog box:
cppdll - Executable for Debugging Session
Please specify the name of the executable file to be
used for the debug session.
Executable file name:
--------------------
| |\/|
--------------------
(3 choices appear if I clicked the drop-down |\/| button):
(Internet Explorer)
(ActiveX Control Test Container)
(regsvr32)
URL where the project can be accessed (ATL Saver only):
--------------------
| |
--------------------

2) If I went to the debug folder of my C:\Documents and
Settings\Scott H. Chang\My Documents\Visual Studio
Project\cppdll\test\debug, and double clicked the
test.exe file. Then the console appeared with the "enter
any number" on the screen - if I typed in any number, the
console just vanished!!!???

I do not understand the problems 1) and 2). Please help
and give me new instructions to solve the problems.

THanks,
Scott Chang
 
1) If I clicked '! Start without Debug' or 'Start' under
the Debug menu, I got the following dialog box:
cppdll - Executable for Debugging Session
Please specify the name of the executable file to be
used for the debug session.
Click to expand...

You cannot run a DLL. You can only run an EXE. Set the EXE project as
the startup project.
2) If I went to the debug folder of my C:\Documents and
Settings\Scott H. Chang\My Documents\Visual Studio
Project\cppdll\test\debug, and double clicked the
test.exe file. Then the console appeared with the "enter
any number" on the screen - if I typed in any number, the
console just vanished!!!???
Click to expand...

Sorry for that. I never use iostream myself. I have tested the following
solution:

int num;

cout << "enter any number: ";
string line;
getline(cin, line);
istringstream line_stream(line);
line_stream >> num;

cout << "cube of number is "
<< cube(num) << endl;

cin.get();

return 0;

You also need to include the following:

#include <iostream>
#include <string>
#include <sstream>
 
Back
Top