How to determine, scriptwise, which function called a function?

[Thanasus]

function a()
{
b();
}

function b()
{
c();
}

function c()
{
}

a();

I am trying to figure out if there is some way a function can determine which function called it. In the example above a calls b and b calls c. Is there anything I can do withing function c that would let me know it was specifically called by function b.

btw- i do not want to have to pass the name of the calling function as a parameter

[ereptur]

I once read a way to do this, but am unable to find it now. The only thing that I could really suggest would be for the function to take an additional string argument. That string would pass the name of the calling function.

e.g.

function a() {
b("a");
}

function b($caller) {
print "Called by $caller";
}

It's not the most glorious way, but until I can find my book and get the proper way, I don't see how else to do it.