1# log.h
2
3
4## Overview
5
6Defines the logging functions of the HiLog module.
7
8Before outputting logs, you must define the service domain, and log tag, use the function with the specified log type and level, and specify the privacy identifier.
9
10Service domain: service domain of logs. You can define the value as required. Its value is a hexadecimal integer ranging from 0x0 to 0xFFFF.
11
12**Log tag**: a string used to identify the class, file, or service behavior.
13
14**Log level**: DEBUG, INFO, WARN, ERROR, or FATAL.
15
16**Parameter format**: printf format string, which starts with a % character, including a parameter type identifier and a variable parameter.
17
18**Privacy identifier**: **{public}** or **{private}** added between the % character and the parameter type identifier in each parameter.
19
20 If no privacy identifier is added, the parameter is considered to be **private**.
21
22Example
23
24Define the service domain and tag:
25
26```
27#define LOG_DOMAIN 0x0201
28#define LOG_TAG "MY_TAG"
29```
30
31Print the log:
32
33```
34HILOG_WARN(LOG_APP, "Failed to visit %{private}s, reason:%{public}d.", url, errno);
35```
36
37Output:
38
39```
4005-06 15:01:06.870 1051 1051 W 0201/MY_TAG: Failed to visit <private>, reason:503.
41```
42
43**File to include**: <hilog/log.h>
44
45**Since**: 8
46
47**Related module**: [HiLog](_hi_log.md)
48
49
50## Summary
51
52
53### Macros
54
55| Name| Description|
56| -------- | -------- |
57| [LOG_DOMAIN](_hi_log.md#log_domain)&nbsp;&nbsp;&nbsp;0 | Defines the service domain for a log file.|
58| [LOG_TAG](_hi_log.md#log_tag)&nbsp;&nbsp;&nbsp;NULL | Defines a string constant used to identify the class, file, or service.|
59| [OH_LOG_DEBUG](_hi_log.md#oh_log_debug)(type, ...)&nbsp;&nbsp;&nbsp;((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), [LOG_DEBUG](_hi_log.md), [LOG_DOMAIN](_hi_log.md#log_domain), [LOG_TAG](_hi_log.md#log_tag), \_\_VA_ARGS\_\_)) | Outputs DEBUG logs. This is a function-like macro.|
60| [OH_LOG_INFO](_hi_log.md#oh_log_info)(type, ...)&nbsp;&nbsp;&nbsp;((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), [LOG_INFO](_hi_log.md), [LOG_DOMAIN](_hi_log.md#log_domain), [LOG_TAG](_hi_log.md#log_tag), \_\_VA_ARGS\_\_)) | Outputs INFO logs. This is a function-like macro.|
61| [OH_LOG_WARN](_hi_log.md#oh_log_warn)(type, ...)&nbsp;&nbsp;&nbsp;((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), [LOG_WARN](_hi_log.md), [LOG_DOMAIN](_hi_log.md#log_domain), [LOG_TAG](_hi_log.md#log_tag), \_\_VA_ARGS\_\_)) | Outputs WARN logs. This is a function-like macro.|
62| [OH_LOG_ERROR](_hi_log.md#oh_log_error)(type, ...)&nbsp;&nbsp;&nbsp;((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), [LOG_ERROR](_hi_log.md), [LOG_DOMAIN](_hi_log.md#log_domain), [LOG_TAG](_hi_log.md#log_tag), \_\_VA_ARGS\_\_)) | Outputs ERROR logs. This is a function-like macro.|
63| [OH_LOG_FATAL](_hi_log.md#oh_log_fatal)(type, ...)&nbsp;&nbsp;&nbsp;((void)HiLogPrint((type), [LOG_FATAL](_hi_log.md), [LOG_DOMAIN](_hi_log.md#log_domain), [LOG_TAG](_hi_log.md#log_tag), \_\_VA_ARGS\_\_)) | Outputs FATAL logs. This is a function-like macro.|
64
65
66### Types
67
68| Name| Description|
69| -------- | -------- |
70| typedef void(\* [LogCallback](_hi_log.md#logcallback)) (const [LogType](_hi_log.md#logtype) type, const [LogLevel](_hi_log.md#loglevel) level, const unsigned int domain, const char \*tag, const char \*msg) | Pointer to the callback function. You can customize the processing of logs in the callback.|
71
72
73### Enums
74
75| Name| Description|
76| -------- | -------- |
77| [LogType](_hi_log.md#logtype) { [LOG_APP](_hi_log.md) = 0 } | Log type.|
78| [LogLevel](_hi_log.md#loglevel) {<br>LOG_DEBUG = 3, LOG_INFO = 4, LOG_WARN = 5, LOG_ERROR = 6, LOG_FATAL = 7<br>} | Log level.|
79
80
81### Functions
82
83| Name| Description|
84| -------- | -------- |
85| int [OH_LOG_Print](_hi_log.md#oh_log_print) ([LogType](_hi_log.md#logtype) type, [LogLevel](_hi_log.md#loglevel) level, unsigned int domain, const char \*tag, const char \*fmt,...) \_\_attribute__((\_\_format__(os_log | Whether to output logs.|
86| int bool [OH_LOG_IsLoggable](_hi_log.md#oh_log_isloggable) (unsigned int domain, const char \*tag, [LogLevel](_hi_log.md#loglevel) level) | Whether logs of the specified service domain, tag, and level can be printed.|
87| void [OH_LOG_SetCallback](_hi_log.md#oh_log_setcallback) ([LogCallback](_hi_log.md#logcallback) callback) | Registered callback function.|
88