memory address represented as a string

Hi all,

I had a quick question:

Let's say I design a function with the signature:

void * foo( char * addr ) ; ,

where addr is a string that represents a valid memory address  ...
so the way someone can call this function is ...

char * addr = "0xae456778" // assume this is a valid memory address on
the machine
foo( addr ) ;

Is it possible to take this address in string form, and assign it to
an actual pointer of void * type ?
I want the function "foo" to return a pointer pointing to the memory
location as indicated
by the string passed in.

Thank you !

Saurabh