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``` 28#define LOG_DOMAIN 0x0201 29#define LOG_TAG "MY_TAG" 30``` 31 32Print the log: 33 34 35``` 36HILOG_WARN(LOG_APP, "Failed to visit %{private}s, reason:%{public}d.", url, errno); 37``` 38 39Output: 40 41 42``` 4305-06 15:01:06.870 1051 1051 W 0201/MY_TAG: Failed to visit <private>, reason:503. 44``` 45 46**Since** 47 488 49 50**Related module** 51 52[HiLog](_hi_log.md) 53 54 55## Summary 56 57 58### Macros 59 60| Name| Description| 61| -------- | -------- | 62| [LOG_DOMAIN](_hi_log.md#log_domain) 0 | Defines the service domain for a log file.| 63| [LOG_TAG](_hi_log.md#log_tag) NULL | Defines a string constant used to identify the class, file, or service.| 64| [OH_LOG_DEBUG](_hi_log.md#oh_log_debug)(type, ...) ((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), LOG_DEBUG, LOG_DOMAIN, LOG_TAG, \_\_VA\_ARGS\_\_)) | Outputs DEBUG logs. This is a function-like macro.| 65| [OH_LOG_INFO](_hi_log.md#oh_log_info)(type, ...) ((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), LOG_INFO, LOG_DOMAIN, LOG_TAG, \_\_VA\_ARGS\_\_)) | Outputs INFO logs. This is a function-like macro.| 66| [OH_LOG_WARN](_hi_log.md#oh_log_warn)(type, ...) ((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), LOG_WARN, LOG_DOMAIN, LOG_TAG, \_\_VA\_ARGS\_\_)) | Outputs WARN logs. This is a function-like macro.| 67| [OH_LOG_ERROR](_hi_log.md#oh_log_error)(type, ...) ((void)[OH_LOG_Print](_hi_log.md#oh_log_print)((type), LOG_ERROR, LOG_DOMAIN, LOG_TAG, \_\_VA\_ARGS\_\_)) | Outputs ERROR logs. This is a function-like macro.| 68| [OH_LOG_FATAL](_hi_log.md#oh_log_fatal)(type, ...) ((void)HiLogPrint((type), LOG_FATAL, LOG_DOMAIN, LOG_TAG, \_\_VA\_ARGS\_\_)) | Outputs FATAL logs. This is a function-like macro.| 69 70 71### Enums 72 73| Name| Description| 74| -------- | -------- | 75| [LogType](_hi_log.md#logtype) { LOG_APP= 0 } | Log type.| 76| [LogLevel](_hi_log.md#loglevel) { LOG_DEBUG = 3, LOG_INFO = 4, LOG_WARN = 5, LOG_ERROR = 6, LOG_FATAL =7 } | Log level.| 77 78 79### Functions 80 81| Name| Description| 82| -------- | -------- | 83| [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, 5, 6))) | Outputs logs.| 84| [OH_LOG_IsLoggable](_hi_log.md#oh_log_isloggable) (unsigned int domain, const char \*tag, [LogLevel](_hi_log.md#loglevel) level) | Checks whether logs of the specified service domain, tag, and level can be printed.| 85