Error handling

Macros
#define	SND_ERROR_BEGIN   500000
#define	SND_ERROR_INCOMPATIBLE_VERSION   (SND_ERROR_BEGIN+0)
#define	SND_LOG_ERROR   1
#define	SND_LOG_WARN   2
#define	SND_LOG_INFO   3
#define	SND_LOG_DEBUG   4
#define	SND_LOG_TRACE   5
#define	SND_LOG_LAST   SND_LOG_TRACE
#define	SND_ILOG_CORE   1
#define	SND_ILOG_CONFIG   2
#define	SND_ILOG_CONTROL   3
#define	SND_ILOG_HWDEP   4
#define	SND_ILOG_TIMER   5
#define	SND_ILOG_RAWMIDI   6
#define	SND_ILOG_PCM   7
#define	SND_ILOG_MIXER   8
#define	SND_ILOG_SEQUENCER   9
#define	SND_ILOG_UCM   10
#define	SND_ILOG_TOPOLOGY   11
#define	SND_ILOG_ASERVER   12
#define	SND_ILOG_LAST   SND_ILOG_ASERVER
#define	snd_error(interface, args...)
#define	snd_errornum(interface, args...)
#define	snd_warn(interface, args...)
#define	snd_info(interface, args...)
#define	snd_debug(interface, args...)
#define	snd_trace(interface, args...)
#define	snd_check(interface, args...)
#define	snd_checknum(interface, args...)
#define	SNDERR(args...)
#define	SYSERR(args...)

Typedefs
typedef void(*	snd_lib_log_handler_t) (int prio, int interface, const char *file, int line, const char *function, int errcode, const char *fmt, va_list arg)
	Log handler callback.
typedef void(*	snd_lib_error_handler_t) (const char *file, int line, const char *function, int errcode, const char *fmt,...)
	Error handler callback.
typedef void(*	snd_local_error_handler_t) (const char *file, int line, const char *func, int errcode, const char *fmt, va_list arg)

Functions
const char *	snd_strerror (int errnum)
	Returns the message for an error code.
int	snd_lib_log_filter (int prio, int interface, const char *configstr)
	Check if a log message should be shown based on LIBASOUND_DEBUG.
void	snd_lib_log (int prio, int interface, const char *file, int line, const char *function, int errcode, const char *fmt,...)
	Root log handler function.
void	snd_lib_check (int interface, const char *file, int line, const char *function, int errcode, const char *fmt,...)
	The check point function.
snd_lib_log_handler_t	snd_lib_log_set_handler (snd_lib_log_handler_t handler)
	Sets the log handler.
snd_lib_log_handler_t	snd_lib_log_set_local (snd_lib_log_handler_t handler)
	Install local log handler.
const char *	snd_lib_log_priority (int prio)
	Function to convert log priority level to text.
const char *	snd_lib_log_interface (int interface)
	Function to convert interface code to text.
int	snd_lib_error_set_handler (snd_lib_error_handler_t handler)
	Sets the error handler.
snd_local_error_handler_t	snd_lib_error_set_local (snd_local_error_handler_t func)
	Install local error handler.

Variables
snd_lib_log_handler_t	snd_lib_vlog
snd_lib_error_handler_t	snd_lib_error
snd_lib_log_handler_t	snd_lib_vlog = snd_lib_vlog_default
snd_lib_error_handler_t	snd_lib_error = snd_lib_error_default

Detailed Description

Error handling macros and functions.

Macro Definition Documentation

snd_check

#define snd_check	(		interface,
			args... )

Value:

snd_lib_check(SND_ILOG_##interface, __FILE__, __LINE__, __func__, 0, ##args)

Shows an check log message.

snd_checknum

#define snd_checknum	(		interface,
			args... )

Value:

snd_lib_check(SND_ILOG_##interface, __FILE__, __LINE__, __func__, errno, ##args)

Shows an check log message (related to errno).

snd_debug

#define snd_debug	(		interface,
			args... )

Value:

snd_lib_log(SND_LOG_DEBUG, SND_ILOG_##interface, __FILE__, __LINE__, __func__, 0, ##args)

Shows an error log message.

snd_error

#define snd_error	(		interface,
			args... )

Value:

snd_lib_log(SND_LOG_ERROR, SND_ILOG_##interface, __FILE__, __LINE__, __func__, 0, ##args)

Shows an error log message.

SND_ERROR_BEGIN

#define SND_ERROR_BEGIN   500000

Lower boundary of sound error codes.

SND_ERROR_INCOMPATIBLE_VERSION

#define SND_ERROR_INCOMPATIBLE_VERSION   (SND_ERROR_BEGIN+0)

Kernel/library protocols are not compatible.

snd_errornum

#define snd_errornum	(		interface,
			args... )

Value:

snd_lib_log(SND_LOG_ERROR, SND_ILOG_##interface, __FILE__, __LINE__, __func__, errno, ##args)

Shows a system error log message (related to errno).

SND_ILOG_ASERVER

#define SND_ILOG_ASERVER   12

aserver

SND_ILOG_CONFIG

#define SND_ILOG_CONFIG   2

configuration parsing and operations

SND_ILOG_CONTROL

#define SND_ILOG_CONTROL   3

control API

SND_ILOG_CORE

#define SND_ILOG_CORE   1

core library code

SND_ILOG_HWDEP

#define SND_ILOG_HWDEP   4

hwdep API

SND_ILOG_LAST

#define SND_ILOG_LAST   SND_ILOG_ASERVER

last known value for interface

SND_ILOG_MIXER

#define SND_ILOG_MIXER   8

mixer API

SND_ILOG_PCM

#define SND_ILOG_PCM   7

PCM API

SND_ILOG_RAWMIDI

#define SND_ILOG_RAWMIDI   6

RawMidi API

SND_ILOG_SEQUENCER

#define SND_ILOG_SEQUENCER   9

sequencer API

SND_ILOG_TIMER

#define SND_ILOG_TIMER   5

timer API

SND_ILOG_TOPOLOGY

#define SND_ILOG_TOPOLOGY   11

topology API

SND_ILOG_UCM

#define SND_ILOG_UCM   10

UCM API

snd_info

#define snd_info	(		interface,
			args... )

Value:

snd_lib_log(SND_LOG_INFO, SND_ILOG_##interface, __FILE__, __LINE__, __func__, 0, ##args)

Shows an error log message.

SND_LOG_DEBUG

#define SND_LOG_DEBUG   4

debug priority level

SND_LOG_ERROR

#define SND_LOG_ERROR   1

error priority level

SND_LOG_INFO

#define SND_LOG_INFO   3

info priority level

SND_LOG_LAST

#define SND_LOG_LAST   SND_LOG_TRACE

last known value for priority level

SND_LOG_TRACE

#define SND_LOG_TRACE   5

trace priority level

SND_LOG_WARN

#define SND_LOG_WARN   2

warning priority level

snd_trace

#define snd_trace	(		interface,
			args... )

Value:

snd_lib_log(SND_LOG_TRACE, SND_ILOG_##interface, __FILE__, __LINE__, __func__, 0, ##args)

Shows an trace log message.

snd_warn

#define snd_warn	(		interface,
			args... )

Value:

snd_lib_log(SND_LOG_WARN, SND_ILOG_##interface, __FILE__, __LINE__, __func__, 0, ##args)

Shows an error log message.

SNDERR

#define SNDERR

(

args...

)

Value:

snd_lib_log(SND_LOG_ERROR, 0, __FILE__, __LINE__, __func__, 0, ##args)

Shows a sound error message.

SYSERR

#define SYSERR

(

args...

)

Value:

snd_lib_log(SND_LOG_ERROR, 0, __FILE__, __LINE__, __func__, errno, ##args)

Shows a system error message (related to errno).

Typedef Documentation

snd_lib_error_handler_t

typedef void(* snd_lib_error_handler_t) (const char *file, int line, const char *function, int errcode, const char *fmt,...)

Error handler callback.

Parameters

file	Source file name.
line	Line number.
function	Function name.
errcode	Value of errno, or 0 if not relevant.
fmt	printf(3) format.
...	printf(3) arguments.

Deprecated

Since 1.2.15

A function of this type is called by the ALSA library when an error occurs. This function usually shows the message on the screen, and/or logs it.

snd_lib_log_handler_t

typedef void(* snd_lib_log_handler_t) (int prio, int interface, const char *file, int line, const char *function, int errcode, const char *fmt, va_list arg)

Log handler callback.

Parameters

prio	Priority (SND_LOG_* defines).
interface	Interface (SND_ILOG_* defines).
file	Source file name.
line	Line number.
function	Function name.
errcode	Value of errno, or 0 if not relevant.
fmt	printf(3) format.
...	printf(3) arguments.

A function of this type is called by the ALSA library when an error occurs. This function usually shows the message on the screen, and/or logs it.

snd_local_error_handler_t

typedef void(* snd_local_error_handler_t) (const char *file, int line, const char *func, int errcode, const char *fmt, va_list arg)

Local error handler function type

Function Documentation

snd_lib_check()

void snd_lib_check	(	int	interface,
		const char *	file,
		int	line,
		const char *	function,
		int	errcode,
		const char *	fmt,
			... )

The check point function.

Parameters

interface	Interface (SND_ILOG_*).
file	The filename where the error was hit.
line	The line number.
function	The function name.
errcode	The error code.
fmt	The message (including the format characters).
...	Optional arguments.

The error message is passed with error priority level to snd_lib_vlog handler.

snd_lib_error_set_handler()

int snd_lib_error_set_handler

(

snd_lib_error_handler_t

handler

)

Sets the error handler.

Parameters

handler

The pointer to the new error handler function.

Deprecated

Since 1.2.15

This function sets a new error handler, or (if handler is NULL) the default one which prints the error messages to stderr.

snd_lib_error_set_local()

snd_local_error_handler_t snd_lib_error_set_local

(

snd_local_error_handler_t

func

)

Install local error handler.

Parameters

func	The local error handler function

Return values

Previous

local error handler function

Deprecated

Since 1.2.15

snd_lib_log()

void snd_lib_log	(	int	prio,
		int	interface,
		const char *	file,
		int	line,
		const char *	function,
		int	errcode,
		const char *	fmt,
			... )

Root log handler function.

Parameters

prio	Priority value (SND_LOG_*).
interface	Interface (SND_ILOG_*).
file	The filename where the error was hit.
line	The line number.
function	The function name.
errcode	The error code.
fmt	The message (including the format characters).
...	Optional arguments.

snd_lib_log_filter()

int snd_lib_log_filter	(	int	prio,
		int	interface,
		const char *	configstr )

Check if a log message should be shown based on LIBASOUND_DEBUG.

Parameters

prio	Priority value (SND_LOG_*).
interface	Interface (SND_ILOG_*).
configstr	Configuration string (usually LIBASOUND_DEBUG environment variable)

Returns

1 if the message should be shown, 0 otherwise.

snd_lib_log_interface()

const char * snd_lib_log_interface

(

int

interface

)

Function to convert interface code to text.

Parameters

interface

Interface (SND_ILOG_*).

Returns

The textual representation of the interface code, or NULL if invalid.

snd_lib_log_priority()

const char * snd_lib_log_priority

(

int

prio

)

Function to convert log priority level to text.

Parameters

prio	Priority value (SND_LOG_*).

Returns

The textual representation of the priority level, or NULL if invalid.

snd_lib_log_set_handler()

snd_lib_log_handler_t snd_lib_log_set_handler

(

snd_lib_log_handler_t

handler

)

Sets the log handler.

Parameters

handler

The pointer to the new log handler function.

Return values

Previous

log handler function

This function sets a new log handler, or (if handler is NULL) the default one which prints the error messages to stderr.

snd_lib_log_set_local()

snd_lib_log_handler_t snd_lib_log_set_local

(

snd_lib_log_handler_t

func

)

Install local log handler.

Parameters

func	The local log handler function

Return values

Previous

local log handler function

snd_strerror()

const char * snd_strerror

(

int

errnum

)

Returns the message for an error code.

Parameters

errnum

The error code number, which must be a system error code or an ALSA error code.

Returns

The ASCII description of the given numeric error code.

Examples

/test/latency.c, /test/pcm.c, /test/pcm_min.c, /test/rawmidi.c, and /test/timer.c.

Variable Documentation

snd_lib_error [1/2]

snd_lib_error_handler_t snd_lib_error

extern

Deprecated

Since 1.2.15 Pointer to the error handler function. For internal use only.

snd_lib_error [2/2]

snd_lib_error_handler_t snd_lib_error = snd_lib_error_default

Deprecated

Since 1.2.15 Pointer to the error handler function. For internal use only.

snd_lib_vlog [1/2]

snd_lib_log_handler_t snd_lib_vlog

extern

Pointer to the error handler function. For internal use only.

snd_lib_vlog [2/2]

snd_lib_log_handler_t snd_lib_vlog = snd_lib_vlog_default

Pointer to the error handler function. For internal use only.