| 0 | N/A | Event verification is successful. | Event logging is normal. No action is required. |
| -1 | Invalid event name | The name is not empty and contains a maximum of 48 characters.<br>The name consists of only the following characters: digits (0 to 9), letters (a to z), and underscore (_).<br>The name does not start with a digit or underscore (_).| Ignore this event and do not perform logging. |
| -1 | Invalid event name | The name is not empty and contains a maximum of 48 characters.<br>The name consists of only the following characters: digits (0 to 9), letters (a to z), and underscore \(_).<br>The name does not start with a digit or underscore \(_).| Ignore this event and do not perform logging. |
| -2 | Invalid event parameter type | The event name must be a string.<br>The event type must be a number.<br>The event parameter must be an object.| Ignore this event and do not perform logging. |
| -4 | Invalid event domain name | The name is not empty and contains a maximum of 32 characters.<br>The name consists of only the following characters: digits (0 to 9), letters (a to z), and underscore (_).<br>The name does not start with a digit or underscore (_).| Ignore this event and do not perform logging. |
| -4 | Invalid event domain name | The name is not empty and contains a maximum of 32 characters.<br>The name consists of only the following characters: digits (0 to 9), letters (a to z), and underscore \(_).<br>The name does not start with a digit or underscore \(_).| Ignore this event and do not perform logging. |
| -99 | Application event logging disabled | Application event logging is disabled. | Ignore this event and do not perform logging. |
| -100 | Unknown error | None. | Ignore this event and do not perform logging. |
| 1 | Invalid key name | The name is not empty and contains a maximum of 16 characters.<br>The name consists of only the following characters: digits (0 to 9), letters (a to z), and underscore (_).<br>The name does not start with a digit or underscore (_).<br>The name does not end with an underscore (_).| Ignore the key-value pair and continue to perform logging. |
| 1 | Invalid key name | The name is not empty and contains a maximum of 16 characters.<br>The name consists of only the following characters: digits (0 to 9), letters (a to z), and underscore \(_).<br>The name does not start with a digit or underscore \(_).<br>The name does not end with an underscore \(_).| Ignore the key-value pair and continue to perform logging. |
| 2 | Invalid key type | The key must be a string. | Ignore the key-value pair and continue to perform logging. |
| 3 | Invalid value type | The supported value types vary depending on the programming language:<br>boolean, number, string, or Array [basic element]| Ignore the key-value pair and continue to perform logging. |
| 4 | Invalid length for values of the string type| For a value of the string type, the maximum length is 8*1024 characters. | Truncate the value with the first 8*1024 characters retained, and continue to perform logging.|
HiAppEvent provides event logging APIs for applications to log the fault, statistical, security, and user behavior events reported during running. Based on event information, you will be able to analyze the running status of your application.
The HiAppEvent module can be used to develop application event-related functions, including flushing application events to a disk and querying historical application events.
## Basic Concepts
The HiAppEvent module can be used to develop application event-related functions, including flushing application events to a disk and querying historical application events.
**Logging**
**Logging**: a function that logs changes caused by user operations to provide service data for development, product, and O&M analysis.
A function that logs changes caused by user operations to provide service data for development, product, and O&M analysis.
