xport_cancel

xport_cancel() controls the ExportLatch owned by the current Hook account and identified by the 32-byte source Export transaction hash W.

With flags == 0, it stops further signature publication but retains the latch, owner reserve, and Import callback readiness.
With flags == tfExportEraseLatch (0x00010000), it erases the latch, releases its reserve, and intentionally forfeits any later callback.
Neither mode revokes signatures already released.
A Hook cannot control the latch being created or consumed by the same currently executing Export or Import transaction.

int64_t xport_cancel (
    uint32_t read_ptr,
    uint32_t read_len,
    uint32_t flags
);

Stop publication and retain the latch:

int64_t result = xport_cancel(SBUF(origin), 0);
if (result != 1)
    rollback(SBUF("Stop Export failed"), 1);

Erase the latch and release reserve:

int64_t result = xport_cancel(SBUF(origin), 0x00010000U);
if (result != 1)
    rollback(SBUF("Erase Export failed"), 1);

Name	Type	Description
`read_ptr`	uint32_t	Pointer to the 32-byte W value returned by `xport()`.
`read_len`	uint32_t	Must be exactly 32.
`flags`	uint32_t	`0` to stop publication and retain the latch, or `tfExportEraseLatch` to erase it.

Returns 1 on success. Negative results include:

Error	Description
`OUT_OF_BOUNDS`	The input pointer or length is outside Hook memory.
`INVALID_ARGUMENT`	W is zero, `read_len` is not 32, or the flags are unsupported.
`PREREQUISITE_NOT_MET`	The current Export or Import execution is creating or consuming this same latch.
`DOESNT_EXIST`	No matching ExportLatch exists for W and the current Hook account.