Proposed helpers (not in the repository)

The following do not exist in hook/macro.h. They are suggestions consistent with the actual API behavior; copy them into your own project if useful. Clearly nothing here is guaranteed by the header.

• REQUIRE_LEN(expr, n, msg) — assert an API call returned exactly n bytes, otherwise rollback. Encodes the "check the byte count" habit from pattern 1/2:

  #define REQUIRE_LEN(expr, n, msg)\
  {\
      if ((expr) != (n))\
          rollback(SBUF(msg), __LINE__);\
  }
  // usage: REQUIRE_LEN(otxn_field(SBUF(dst), sfDestination), 20, "bad destination");

• CHECK(expr) — evaluate an API call, and if it is negative, return that error code as a rollback. A terser form of the pattern-1 if (x < 0) NOPE(...):

  #define CHECK(expr)\
  {\
      int64_t _r = (expr);\
      if (_r < 0)\
          return rollback(0, 0, _r);\
  }

These mirror behavior of the real API (non-negative success / negative error) but are my own proposals, not part of the shipped header. Prefer the in-repo macros (ASSERT, REQUIRE, NOPE) unless you have a specific reason to extend them.