#define TV_SUB (a,b,c) #define return_if_no_current_trace (tr) #define return_val_if_no_current_trace (tr, val) #define TOUCH (x)
#define TV_SUB(a,b,c)
#define return_if_no_current_trace(tr)
#define return_val_if_no_current_trace(tr, val)
#define TOUCH(x) { x = 0; }