vtobool
if (!vtobool(a, v->v_num, v->v_num))
default_smooth = vtobool(a, v->v_num, v->v_num);
debug = vtobool(a, debug, debug);
flag = vtobool(++a, v->v_num, v->v_num);
setterse(vtobool(a, terse, terse));
char vtobool(struct value *, char, char);
if ((haspty = vtobool(++a, 1, -1)) < 0)
if ((hasframe = vtobool(++a, 1, -1)) < 0)
if ((mapnl = vtobool(++a, !haspty, -1)) < 0)
if ((keepopen = vtobool(++a, 0, -1)) < 0)
if ((smooth = vtobool(++a, default_smooth, -1)) < 0)