Calling functions while in debug mode in VC++ (Immediate Window)

Question

I wonder can I call functions during the debug mode in VC++? Assume that I have a function to which I set a break point at, when the execution stops at that point during debugging, can I call other functions and see their results before proceeding to the next line of code?

Solution 1

I believe you can. I think its called Immediate Window. I use VS2010 Ultimate, so I don't know if it exists in your version.

Ctrl + Alt + I

But this only prints output for when the function returns a value. Also, it may not work in some cases.

Let's say you have :

#include <iostream>

int number = 10; //global
void setNumber(int n);

int main()
{
    std::cout<<std::endl; //breakpoint 1 here
    setNumber(4);
    std::cout<<std::endl; //breakpoint 2 here
}

int getNumberSquared()
{
    return number * number;
}

void setNumber(int n)
{
    number = n;
}

when you encounter breakpoint 1, press the shortcut and type:

getNumberSquared()

The output will be 100 After encountering breakpoint 2, do the same thing and the output will be 16

Solution 2

Visual studio has the option to jump to a specific statement (right click + set next statement or ctrl+shift+F10), but be aware when doing so. A function call requires registries to be valid, which will most likely not be if you jump across classes or out of scope.

Comments

[Jawad]

Thanks. I did that and got this error: CXX0052: Error: member function not present. I'm using pre-compiled libraries with no source code, and hence I can't step into any of their functions; however, tech. support says that I should still be able to call any of the functions in the library and view its output in the debug mode, something like finding the size of an array.

[Luchian Grigore]

@Jawad this is by design of course. No way for the runtime to know what you want...

[devjeetroy]

ah, as I said, the interactive mode does not work always. But mostly it does. I woudldn't be able to tell you anything about it's compatibility with libraries.

[Jawad]

Thank you. I'll try other functions, hopefully something will work.