Report-buffer builders

These construct a human-readable C-string containing a label and a base-10 integer — useful for trace output or for a message passed to accept/rollback.

RBUF / RBUF2

#define RBUF(buf, out_len, str, num) /* declares `buf` and `out_len`, fills them */
#define RBUF2(buff, out_len, str, num, str2, num2) /* two label+number pairs */

Both are statement/declaration macros: they declare the named buffer and an int out_len for you and then populate them, so use them at the point you want those variables to come into scope — not inside an expression, and not with a name that already exists. RBUF emits str followed by the decimal form of num; RBUF2 appends a second str2+num2. Negative numbers get a leading -. The buffer is sized sizeof(str) + 21 (a 64-bit integer is at most 20 digits plus sign), and NUL terminated; out_len is the string length excluding the NUL. Their internal digit loops are guarded with GUARDM.

// declares `msg` (a char array) and `msg_len`:
RBUF(msg, msg_len, "ledger seq = ", ledger_seq());
trace(SBUF("info"), msg, msg_len, 0);   // -> "ledger seq = 1234567"

RBUF2(rep, rep_len, "in=", incoming, " out=", outgoing);
accept(rep, rep_len, 0);

Caveat: because they declare variables, you cannot call RBUF(x, n, ...) twice with the same x/n in the same scope. Pick fresh names or open a new block.