Function origin

When I call a function X in multiple places (main, from within other functions) is it possible to know each time X was called what part of the code called it, or do I have to pass flags with each call telling the function X where it was called ?

I assume you want to do this in code, rather than using development/debugging tools (which rely on support by the compiler to include information they can use).

The only way is to provide the information yourself (eg additional arguments). For example;

Code:

---

#include <iostream>

void func(const char *file, int line)
{
    std::cout << "Called from source file " << file << " Line " << line << '\n';
}

int main()
{
    func(__FILE__, __LINE__);
}

---

In C (as per 1999 standard) also supports a __func__ predefined identifier that gives the name of the calling function. This is not supported in C++ or the preceding 1989/90 C standard. There is no direct way to get the line number relative to a function; __LINE__ represents the line number in the source file.

In C++, if you want to pass the calling function name, you have to do it yourself. For example;

Code:

---

#include <iostream>

void func(const char *caller)
{
    std::cout << "Called by " << caller <<  '\n';
}

int main()
{
    const char function_name[] = "int main()";
    func(function_name);
}

---

There are non-standard extensions, of course. They might be preferable to hand-coding like that. You might even define the macros depending on if it's compiler X or the rest to make it portable.

But the real question is, why do you want to know?

Because I have a function that prints contents of an array, it is used multiple times.
The first line is:

Code:

---

cout << "Array  " << what << " = ";

---

what can be "created", "updated", "deleated" ...
Right now I am passing it along with the array to the function.

So I wanted to know is there a different way to do this.

Quote:

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Originally Posted by Suchy

what can be "created", "updated", "deleated" ...
Right now I am passing it along with the array to the function.

---

Sounds like the right way of doing it. Why do you seek an alternative? I don't see how the name of the array necessarily relates to the name of the function which calls the array print function... In fact, coupling the two borders on insane.

You could use something like the StackTrace class I created in this thread: http://cboard.cprogramming.com/windows-programming/101268-stacktrace-implementation.html

Thanks for the replys, I will stick with my original way.
But thanks for the ideas.