Detect uninitialized memory in gdb

Greetings.

Suppose I have the following codes:

struct X { ... };

void g(struct X *x_p);

void f()
{
   struct X x_var;
   g(&x_var);
}

In the function of g,  I want to check the data where x_p point to,
however it is possible that it is not initialized like above code. So
do we have a way to detect that the memory x_p point to is not
initialized or not in gdb?

Best Regards
Andy Fan