util_raddr

Summary. Convert a 20-byte AccountID into its base58-check encoded r-address string (e.g. rB6v18pQ765Z9DH5RQsTFevoQPFmRtBqhT). This is the inverse of util_accid.

Signature.

int64_t util_raddr(
    uint32_t write_ptr,   // where to write the r-address string
    uint32_t write_len,   // capacity of the write buffer
    uint32_t read_ptr,    // 20-byte AccountID to encode
    uint32_t read_len);   // must be 20

Parameters.

Name	Meaning
write_ptr, write_len	Output buffer for the ASCII r-address. Encoded r-addresses are up to 35 characters; a 50-byte buffer is a safe upper bound. Not NUL-terminated by the API — the return value is the byte count.
read_ptr, read_len	The AccountID to encode. read_len must be exactly 20.

Return value. On success, the number of bytes written (the r-address length). Errors:

Code	Value	Cause
OUT_OF_BOUNDS	-1	write or read region is out of WASM memory bounds.
TOO_SMALL	-4	write_len is smaller than the encoded r-address.
INVALID_ARGUMENT	-7	read_len was not exactly 20.

Common failure patterns.

• Passing a raw public key (33 bytes) or a keylet (34 bytes) instead of a 20-byte AccountID → INVALID_ARGUMENT.
• Sizing the output buffer to 20 bytes (AccountID length) instead of ~35 → TOO_SMALL.

Caveats. The output is not NUL-terminated. Use the return value as the length; if you need a C string, write a \0 yourself at write_ptr + returnvalue.

Minimal example.

uint8_t accid[20]; // filled elsewhere, e.g. via hook_account
hook_account(SBUF(accid));

uint8_t r[50];
int64_t len = util_raddr(SBUF(r), SBUF(accid));
if (len < 0)
    rollback(SBUF("util_raddr failed"), len);
// r[0..len) now holds the ASCII r-address

Practical example. Building a human-readable trace line for the account a hook is installed on:

uint8_t accid[20];
hook_account(SBUF(accid));
uint8_t r[50];
int64_t len = util_raddr(SBUF(r), SBUF(accid));
if (len > 0)
    trace(SBUF("hook account"), r, len, 0); // logs the r-address as text

Related APIs. util_accid, hook_account, otxn_field (to obtain an AccountID field).