/* MUST.H -- error checking worthy of C */

/* must be (non-zero) */
#define MUST(err, func, ...)			\
  if (!(func(__VA_ARGS__))) err(func)
/* must be ZERO */
#define MUSTZ(err, func, ...)			\
  if ((func(__VA_ARGS__))) err(func)
/* must be POSITIVE */
#define MUSTP(err, func, ...)			\
  if ((func(__VA_ARGS__)) < 0) err(func)
/* must (equal specific) VALUE */
#define MUSTV(err, val, func, ...)		\
  if (val == (func(__VA_ARGS__))) err(func)
/* must NOT (equal value) */
#define MUSTN(err, val, func, ...)		\
  if (val != (func(__VA_ARGS__))) err(func)
/* must NOT (equal value) */
#define MUSTN(err, val, func, ...)		\
  if (val != (func(__VA_ARGS__))) err(func)

/* must ASSIGN (non-zero) */
#define MUSTA(err, var, func, ...)		\
  if (!(var = (func(__VA_ARGS__)))) err(func)
/* must ASSIGN POSITIVE (value) */
#define MUSTAP(err, var, func, ...)			\
  if ((var = (func(__VA_ARGS__))) < 0) err(func)
/* must ASSIGN (value) NOT (equal) */
#define MUSTAN(err, var, val, func, ...)		\
  if (val != (var = (func(__VA_ARGS__)))) err(func)

/* must DECLARE (non-zero) */
#define MUSTD(err, type, var, func, ...)		\
  type var; if (!(var = (func(__VA_ARGS__)))) err(func)
/* must DECLARE POSITIVE (value) */
#define MUSTDP(err, type, var, func, ...)			\
  type var; if ((var = (func(__VA_ARGS__))) < 0) err(func)
/* must DECLARE POSITIVE (value) */
#define MUSTDN(err, type, var, val, func, ...)				\
  type var; if (val != (var = (func(__VA_ARGS__))) < 0) err(func)

/* HIGHER ORDER MACROS */

/* return negative */
#define RN(func) do { perror(#func); return -1; } while (0)
/* quit fatally */
#define QF(func) do { perror(#func); abort(); } while (0)
/* warn and continue */
#define WC(func) do { perror(#func); goto contin; } while (0)
/* manual action */
#define MA(func)

#define OTHERWISE() 0
#define ERREQ(no) errno == no