simple question

[mangocinn]

I am new to C++... please help.

I am using Visual C++ (using MFC).

FunctionA looks like this.
FunctionA(Long* pVal)

I know I can call function A like so..
long bRet;
FunctionA(&bRet);

However if I want to pass the return value as a parameter of another function (FunctionB) call... how do I do that.
I tried
FunctionB(FunctionA())...and it is expecting a parameter. The parameter is just the output.

What is the trick?

Few additional questions:
How do I convert BSTR to std::string?
How do I convert Long to int?

 

[BlackDice]

Your call should look like this:

FunctionB(FunctionA(&bRet));

you still have to supply a parameter to FunctionA().

to convert long to int:

int nNum = (int) lNumber;

or 

int nNum = static_cast<int>(lNumber);

I think using static_cast will catch the error at compile time if you try to convert to a wrong type. also, remember that since a long has more bytes than the int, you could lose part of your number, and your compiler will probably give you a warning about this.

I'm doing this off the top of my head, so I can't really remember the BSTR to std::string one. Maybe convert the BSTR to a LPCTSTR or char*,then convert to std::string.

hope this helps.



BlackDice

http://www.stillwaterexpress.com

 

[cpjust]

In 32-bit Operating Systems, long and int are both 4 bytes long.

 

[mangocinn]

Thank you both... it works!