Logging

Files
file	log.h

Classes
struct	__android_log_message

Macros
#define	__INTRODUCED_IN(x)

Typedefs
typedef enum android_LogPriority	android_LogPriority
typedef int int void enum log_id	log_id_t
typedef void(*	__android_logger_function) (const struct __android_log_message *log_message)
typedef void(*	__android_aborter_function) (const char *abort_message)

Enumerations
enum	android_LogPriority {   ANDROID_LOG_UNKNOWN = 0 , ANDROID_LOG_DEFAULT , ANDROID_LOG_VERBOSE , ANDROID_LOG_DEBUG ,   ANDROID_LOG_INFO , ANDROID_LOG_WARN , ANDROID_LOG_ERROR , ANDROID_LOG_FATAL ,   ANDROID_LOG_SILENT }
enum	log_id {   LOG_ID_MIN = 0 , LOG_ID_MAIN = 0 , LOG_ID_RADIO = 1 , LOG_ID_EVENTS = 2 ,   LOG_ID_SYSTEM = 3 , LOG_ID_CRASH = 4 , LOG_ID_STATS = 5 , LOG_ID_SECURITY = 6 ,   LOG_ID_KERNEL = 7 , LOG_ID_MAX , LOG_ID_DEFAULT = 0x7FFFFFFF }

Functions
int	__android_log_write (int prio, const char *tag, const char *text)
int	__android_log_print (int prio, const char *tag, const char *fmt,...) __attribute__((__format__(printf
int int	__android_log_vprint (int prio, const char *tag, const char *fmt, va_list ap) __attribute__((__format__(printf
int int void	__android_log_assert (const char *cond, const char *tag, const char *fmt,...) __attribute__((__noreturn__)) __attribute__((__format__(printf
int	__android_log_buf_write (int bufID, int prio, const char *tag, const char *text)
int	__android_log_buf_print (int bufID, int prio, const char *tag, const char *fmt,...) __attribute__((__format__(printf
void	__android_log_write_log_message (struct __android_log_message *log_message) __INTRODUCED_IN(30)
void	__android_log_set_logger (__android_logger_function logger) __INTRODUCED_IN(30)
void	__android_log_logd_logger (const struct __android_log_message *log_message) __INTRODUCED_IN(30)
void	__android_log_stderr_logger (const struct __android_log_message *log_message) __INTRODUCED_IN(30)
void	__android_log_set_aborter (__android_aborter_function aborter) __INTRODUCED_IN(30)
void	__android_log_call_aborter (const char *abort_message) __INTRODUCED_IN(30)
void	__android_log_default_aborter (const char *abort_message) __attribute__((noreturn)) __INTRODUCED_IN(30)
int	__android_log_is_loggable (int prio, const char *tag, int default_prio) __INTRODUCED_IN(30)
int	__android_log_is_loggable_len (int prio, const char *tag, size_t len, int default_prio) __INTRODUCED_IN(30)
int32_t	__android_log_set_minimum_priority (int32_t priority) __INTRODUCED_IN(30)
int32_t	__android_log_get_minimum_priority (void) __INTRODUCED_IN(30)
void	__android_log_set_default_tag (const char *tag) __INTRODUCED_IN(30)

Detailed Description

Macro Definition Documentation

__INTRODUCED_IN

#define __INTRODUCED_IN

(

x

)

Typedef Documentation

__android_aborter_function

typedef void(* __android_aborter_function) (const char *abort_message)

Prototype for the 'abort' function that is called when liblog will abort due to __android_log_assert() failures.

__android_logger_function

typedef void(* __android_logger_function) (const struct __android_log_message *log_message)

Prototype for the 'logger' function that is called for every log message.

android_LogPriority

typedef enum android_LogPriority android_LogPriority

Android log priority values, in increasing order of priority.

log_id_t

typedef int int void enum log_id log_id_t

Identifies a specific log buffer for __android_log_buf_write() and __android_log_buf_print().

Enumeration Type Documentation

android_LogPriority

enum android_LogPriority

Android log priority values, in increasing order of priority.

Enumerator
ANDROID_LOG_UNKNOWN	For internal use only.
ANDROID_LOG_DEFAULT	The default priority, for internal use only.
ANDROID_LOG_VERBOSE	Verbose logging. Should typically be disabled for a release apk.
ANDROID_LOG_DEBUG	Debug logging. Should typically be disabled for a release apk.
ANDROID_LOG_INFO	Informational logging. Should typically be disabled for a release apk.
ANDROID_LOG_WARN	Warning logging. For use with recoverable failures.
ANDROID_LOG_ERROR	Error logging. For use with unrecoverable failures.
ANDROID_LOG_FATAL	Fatal logging. For use when aborting.
ANDROID_LOG_SILENT	For internal use only.

log_id

enum log_id

Identifies a specific log buffer for __android_log_buf_write() and __android_log_buf_print().

Enumerator
LOG_ID_MIN
LOG_ID_MAIN	The main log buffer. This is the only log buffer available to apps.
LOG_ID_RADIO	The radio log buffer.
LOG_ID_EVENTS	The event log buffer.
LOG_ID_SYSTEM	The system log buffer.
LOG_ID_CRASH	The crash log buffer.
LOG_ID_STATS	The statistics log buffer.
LOG_ID_SECURITY	The security log buffer.
LOG_ID_KERNEL	The kernel log buffer.
LOG_ID_MAX
LOG_ID_DEFAULT	Let the logging function choose the best log target.

Function Documentation

__android_log_assert()

int int void __android_log_assert	(	const char *	cond,
		const char *	tag,
		const char *	fmt,
			...
	)

Writes an assertion failure to the log (as ANDROID_LOG_FATAL) and to stderr, before calling abort(3).

If fmt is non-null, cond is unused. If fmt is null, the string Assertion failed: s is used with cond as the string argument. If both fmt and cond are null, a default string is provided.

Most callers should use assert(3) from <assert.h> instead, or the __assert and __assert2 functions provided by bionic if more control is needed. They support automatically including the source filename and line number more conveniently than this function.

__android_log_buf_print()

int __android_log_buf_print	(	int	bufID,
		int	prio,
		const char *	tag,
		const char *	fmt,
			...
	)

Writes a formatted string to log buffer id, with priority prio and tag tag. The details of formatting are the same as for printf(3).

Apps should use __android_log_print() instead.

__android_log_buf_write()

int __android_log_buf_write	(	int	bufID,
		int	prio,
		const char *	tag,
		const char *	text
	)

Writes the constant string text to the log buffer id, with priority prio and tag tag.

Apps should use __android_log_write() instead.

__android_log_call_aborter()

void __android_log_call_aborter

(

const char *

abort_message

)

Calls the stored aborter function. This allows for other logging libraries to use the same aborter function by calling this function in liblog.

Parameters

abort_message

an additional message supplied when aborting, for example this is used to call android_set_abort_message() in __android_log_default_aborter().

Available since API level 30.

__android_log_default_aborter()

void __android_log_default_aborter

(

const char *

abort_message

)

Sets android_set_abort_message() on device then aborts(). This is the default aborter.

Parameters

abort_message

an additional message supplied when aborting. This functions calls android_set_abort_message() with its contents.

Available since API level 30.

__android_log_get_minimum_priority()

int32_t __android_log_get_minimum_priority

(

void

)

Gets the minimum priority that will be logged for this process. If none has been set by a previous __android_log_set_minimum_priority() call, this returns ANDROID_LOG_DEFAULT.

Returns

the current minimum priority as android_LogPriority values, or ANDROID_LOG_DEFAULT if none is set.

Available since API level 30.

__android_log_is_loggable()

int __android_log_is_loggable	(	int	prio,
		const char *	tag,
		int	default_prio
	)

Use the per-tag properties "log.tag.<tagname>" along with the minimum priority from __android_log_set_minimum_priority() to determine if a log message with a given prio and tag will be printed. A non-zero result indicates yes, zero indicates false.

If both a priority for a tag and a minimum priority are set by __android_log_set_minimum_priority(), then the lowest of the two values are to determine the minimum priority needed to log. If only one is set, then that value is used to determine the minimum priority needed. If none are set, then default_priority is used.

Parameters

prio	the priority to test, takes android_LogPriority values.
tag	the tag to test.
default_prio	the default priority to use if no properties or minimum priority are set.

Returns

an integer where 1 indicates that the message is loggable and 0 indicates that it is not.

Available since API level 30.

__android_log_is_loggable_len()

int __android_log_is_loggable_len	(	int	prio,
		const char *	tag,
		size_t	len,
		int	default_prio
	)

Use the per-tag properties "log.tag.<tagname>" along with the minimum priority from __android_log_set_minimum_priority() to determine if a log message with a given prio and tag will be printed. A non-zero result indicates yes, zero indicates false.

If both a priority for a tag and a minimum priority are set by __android_log_set_minimum_priority(), then the lowest of the two values are to determine the minimum priority needed to log. If only one is set, then that value is used to determine the minimum priority needed. If none are set, then default_priority is used.

Parameters

prio	the priority to test, takes android_LogPriority values.
tag	the tag to test.
len	the length of the tag.
default_prio	the default priority to use if no properties or minimum priority are set.

Returns

an integer where 1 indicates that the message is loggable and 0 indicates that it is not.

Available since API level 30.

__android_log_logd_logger()

void __android_log_logd_logger

(

const struct __android_log_message *

log_message

)

Writes the log message to logd. This is an __android_logger_function and can be provided to __android_log_set_logger(). It is the default logger when running liblog on a device.

Parameters

log_message

the log message to write, see __android_log_message.

Available since API level 30.

__android_log_print()

int __android_log_print	(	int	prio,
		const char *	tag,
		const char *	fmt,
			...
	)

Writes a formatted string to the log, with priority prio and tag tag. The details of formatting are the same as for printf(3).

__android_log_set_aborter()

void __android_log_set_aborter

(

__android_aborter_function

aborter

)

Sets a user defined aborter function that is called for __android_log_assert() failures. This user defined aborter function is highly recommended to abort and be noreturn, but is not strictly required to.

Parameters

aborter

the new aborter function, see __android_aborter_function.

Available since API level 30.

__android_log_set_default_tag()

void __android_log_set_default_tag

(

const char *

tag

)

Sets the default tag if no tag is provided when writing a log message. Defaults to getprogname(). This truncates tag to the maximum log message size, though appropriate tags should be much smaller.

Parameters

tag	the new log tag.

Available since API level 30.

__android_log_set_logger()

void __android_log_set_logger

(

__android_logger_function

logger

)

Sets a user defined logger function. All log messages sent to liblog will be set to the function pointer specified by logger for processing. It is not expected that log messages are already terminated with a new line. This function should add new lines if required for line separation.

Parameters

logger

the new function that will handle log messages.

Available since API level 30.

__android_log_set_minimum_priority()

int32_t __android_log_set_minimum_priority

(

int32_t

priority

)

Sets the minimum priority that will be logged for this process.

Parameters

priority

the new minimum priority to set, takes android_LogPriority values.

Returns

the previous set minimum priority as android_LogPriority values, or ANDROID_LOG_DEFAULT if none was set.

Available since API level 30.

__android_log_stderr_logger()

void __android_log_stderr_logger

(

const struct __android_log_message *

log_message

)

Writes the log message to stderr. This is an __android_logger_function and can be provided to __android_log_set_logger(). It is the default logger when running liblog on host.

Parameters

log_message

the log message to write, see __android_log_message.

Available since API level 30.

__android_log_vprint()

int int __android_log_vprint	(	int	prio,
		const char *	tag,
		const char *	fmt,
		va_list	ap
	)

Equivalent to __android_log_print, but taking a va_list. (If __android_log_print is like printf, this is like vprintf.)

__android_log_write()

int __android_log_write	(	int	prio,
		const char *	tag,
		const char *	text
	)

Writes the constant string text to the log, with priority prio and tag tag.

__android_log_write_log_message()

void __android_log_write_log_message

(

struct __android_log_message *

log_message

)

Writes the log message specified by log_message. log_message includes additional file name and line number information that a logger may use. log_message is versioned for backwards compatibility. This assumes that loggability has already been checked through __android_log_is_loggable(). Higher level logging libraries, such as libbase, first check loggability, then format their buffers, then pass the message to liblog via this function, and therefore we do not want to duplicate the loggability check here.

Parameters

log_message

the log message itself, see __android_log_message.

Available since API level 30.