rollback

Concepts

• Introduction

• Execution Order

Behaviour

End the execution of the hook with status: reject.

• Record a return string and return code in transaction metadata.

• Discard all state changes.

• Discard all emit() transactions.

• Disallow originating transaction to continue.

❗️Warning

The originating transaction will fail with tecHOOK_REJECTED and a fee will be charged. See: Execution Order.

Definition

C

int64_t rollback (
    uint32_t read_ptr,
    uint32_t read_len,
    uint64_t error_code
);

Javascript

function rollback(error_msg: string, error_code: number): number

Example

C

rollback("Rejected!", 9, 100);

Javascript

rollback('Rejected!', 100)

Parameters

C

Name	Type	Description
read_ptr	uint32_t	Pointer to a return string to be stored in execution metadata. This is any string the hook-developer wishes to return with the acceptance. May be null.
read_len	uint32_t	The length of the return string. At most 32. May be null.
error_code	uint64_t	A return code specific to this hook to be stored in execution metadata. Similar to the return code of an application on a *nix system. By convention non-success is non-zero.

Javascript

Name	Type	Description
error_msg	string	String to be stored in execution metadata. This is any string the hook-developer wishes to return with the acceptance. May be null.
error_code	number	A return code specific to this hook to be stored in execution metadata. Similar to the return code of an application on a *nix system. By convention non-success is non-zero.

Return Code

C

Type	Description
int64_t	Rollback ends the hook, therefore no value is returned to the caller. By convention all Hook APIs return int64_t, but in this case nothing is returned.

Javascript

Type	Description
number	Rollback ends the hook, therefore no value is returned to the caller. By convention all Hook APIs return number, but in this case nothing is returned.