arg
arg(Node **a, int nnn) /* nth argument of a function */
arg(struct tbl_node *tbl, int ln, const char *p, int *pos, int key)
#define arg(n) (c < (n) ? nullstr: ap[n])
typedef struct arg {
struct arg {
void arg(int a, int *p, int (*fb)(unsigned char), int (*fi)(int), int (*fl)(long), int (*fv)(void), int (*fip)(int *), int (*fim)(int (*)[3]), int (*fvp)(void *), int (*ffp)(int (*)(int)))