Is it possible to find out the variable name, the pointer pointing to?

Question

Is it Possible to get the name of array the pointer pointing to?

example:

 char name[20];
 char *p = name
 int door_no;
 int *q = &door_no


        

Answer 1

No, you can't do that. The names of variables do not even exist after your code is compiled and linked (unless you're keeping debugging information around), so you can't get at it at run time.

In C (in contrast to very dynamic languages such as JavaScript or classical Lisp), the only role of variable names is to tell the compiler/linker which declaration you're pointing at when you mention a variable in the source code. Once these connections have been made and represented in the compiler's internal data structures, there is no further use for the names (again, except for debugging and/or pretty-printing of error messages from the compiler).

Answer 2

Everything that Henning said before me is correct. In addition, the target of a pointer might not even have a variable name. For example, consider:

char a;
char *ptr = &a + 5;

Now ptr is pointing somewhere that doesn't have anything to do with a (and in fact might be pointing outside of the memory allocated for your program and doing anything with that pointer could cause a segmentation fault).

Answer 3

It is not possible to get the name of the variables p or q point to if you compile and execute the program traditionally, because one of the things the compiler does is forget the name of the variables, keeping only addresses.

Depending on what you are trying to do, you may execute the program in a non-traditional execution environment where the names are preserved. For instance,

~ $ cat t.c
main(){
 char name[20];
 char *p=name;
 int door_no;
 int *q= & door_no;
}
~ $ frama-c -val t.c
[kernel] preprocessing with "gcc -C -E -I.  t.c"
...
[value] ====== VALUES COMPUTED ======
[value] Values for function main:
          p ∈ {{ &name ;}}
          q ∈ {{ &door_no ;}}
          __retres ∈ {0; }