Macros
#define	LOG_ALL_CHANNELS 0, 256
	This is a short-cut to define the parameters of all channels in one single call to logSetChannels().

#define	LOG_ASSERT(cond)
	Assertion using `larlib.log` for output. More...

Typedefs
typedef int(*	logWriteFunction_t) (void context, uint16_t channelLevel, const char msg, int msgLength)
	Type of the function that does the actual writing on a trace channel. More...

typedef int(*	logDumpFunction_t) (logWriteFunction_t write, void context, uint16_t channelLevel, const void data, int dataLen)
	Type of function called to format the output on logDump(). More...

Enumerations
enum	logLevel_t { LOG_DEBUG = 0x0000, LOG_INFO = 0x2000, LOG_WARNING = 0x4000, LOG_ERROR = 0x6000, LOG_CRITICAL = 0x8000, LOG_ALWAYS = 0xFF00 }
	General tracing levels. More...

enum	logReservedChannels_t { LOG_CH_BASE = 200, LOG_CH_CONV, LOG_CH_DATE, LOG_CH_FS, LOG_CH_INI, LOG_CH_MEM, LOG_CH_TAB, LOG_CH_STEP, LOG_CH_FORMAT, LOG_CH_TASK }
	List of reserved log channels. More...

Functions
int	logWriteTeliumTrace (void context, uint16_t channelLevel, const char msg, int msgLength)
	A logWriteFunction_t that can be used as parameter to logSetChannels() and writes traces using Telium's `trace()` function. More...

int	logWriteTeliumRemoteDebugger (void context, uint16_t channelLevel, const char msg, int msgLength)
	A logWriteFunction_t that can be used as parameter to logSetChannels() and writes traces to the Remote Debugger console on IngeDev. More...

int	logDumpFormattedAscii (logWriteFunction_t write, void context, uint16_t channelLevel, const void data, int dataLen)
	`dumpFormatFunction` that formats the received buffer as a two-column hexadecimal and ASCII display and calls the received `write` function. More...

int	logSetChannels (uint8_t firstChannel, int numChannels, uint16_t level, logWriteFunction_t writeFunction, logDumpFunction_t dumpFormatFunction, void *context)
	Configures one or more tracing channels. More...

int	logChannelIsEnabled (uint16_t channelLevel)
	Check if a log channel is enabled for a specific priority level. More...

int	logPrintf (uint16_t channelLevel, const char *fmt,...)
	`sprintf()` like formatted traces. More...

int	logPrintvf (uint16_t channelLevel, const char *fmt, va_list va)
	A version of logPrintf() that accepts a `va_list` as parameter. More...

int	logDump (uint16_t channelLevel, const void *buffer, int size)
	Write a block of data as a binary dump. More...

Detailed Description

Rationale

Tracing is one of the basic helper tools for debugging. Defining a common tracing API that can be used by all LAR libraries and modules makes easier for them to interact. Nevertheless tracing should be optional and highly customizable.

Introduction

The larlib.log module provides a general logging/tracing system with assertions and other helper routines. It is designed to be easily ported to any platform.

Its mechanics are based on the concept of tracing channels: 256 channels are available, and each one can be separately configured to be disabled, or enabled with a given configuration. An application can use different channel IDs to different modules so to conditionally enable tracing of specific modules.

By default all channels are disabled.

Note: Channel numbers 200 and higher are reserved for LAR's internal libraries and modules and should not be used by applications.

Given that tracing is very platform dependent, this library takes the position that all platform-dependency is moved to the configuration step, and after that the actual tracing code should not need to change.

Setup

Each channel has a separated configuration, and each configuration includes, information about how to write, and the tracing level in use.

The tracing level of a given channel is a number that define the priority of the trace. On run-time only traces with a priority value larger than or equal to the configured priority of this channel are actually written.

For example, to have all tracing disabled, except for the channel number 42, which should only print errors or higher priority:

// disable all channels (this is the default)
logSetChannels(LOG_ALL_CHANNELS, 0, NULL, NULL, NULL);
// enable only channel 42
logSetChannels(42, 1, LOG_ERROR, myWriteFunction,
 myDumpFormatFunction, myContext);

For each channel a write function should be given, this function is unique for each platform and device, and a format function may also be given.

In platforms and devices where the write function expects binary data (Telium's trace() for instance) the format function may not be given, and all binary data written using logDump() will be directly sent to the write function.

In platforms where the write function only accepts ASCII chars (the printer for example) then the format function must be given and it should convert the binary data received by logDump() to a printable (ASCII-only) format. The provided function logDumpFormattedAscii() is an example of this formatting function, and will convert the binary data to a two-column hexadecimal/ascii format.

Telium

The Telium platform has a built-in system for tracing, using the trace() function. Also, each trace may have an associated code (called its SAP code).

To use the built-in trace() function, use logWriteTeliumTrace() as writeFunction and NULL as dumpFormatFunction parameters to logSetChannels().

logSetChannels(<firstChannel>, <channelCount>, <logLevel>, logWriteTeliumTrace, NULL, (void *) <sapCode>);

Tracing

After the configuration is done using logSetChannels(), one should use logPrintf(), logPrintvf() or logDump() to output traces:

// this trace has LOG_ERROR priority
logPrintf(42|LOG_ERROR, "Failed at %s with error %d", functionName, errorCode);
// But those only print if LOG_DEBUG level is active for channel 42:
logPrintf(42, "Result buffer:");
logDump(42, buffer, bufferSize);

LOG_ASSERT() uses channel LOG_CH_BASE to display the assertion failure message and resets the device. If channel LOG_CH_BASE is not enabled the message is not displayed, but the device will be reseted anyway. See logReservedChannels_t.

Macro Definition Documentation

#define LOG_ASSERT ( cond )

Assertion using larlib.log for output.

If cond evaluates to zero, write an error message on channel LOG_CH_BASE and either halt execution or reset the device.

Typedef Documentation

typedef int(* logDumpFunction_t) (logWriteFunction_t write, void *context, uint16_t channelLevel, const void *data, int dataLen)

Type of function called to format the output on logDump().

It should call the received write function to actually output the formatted data.

Parameters

write	The function to call to actually generate the trace
context	The same `context` variable that is passed as parameter to logSetChannels()
channelLevel	Channel and level that triggered this trace
data	Pointer to binary data to write.
dataLen	Length of `data`, in bytes.

Returns: Zero on success, non-zero on error.

typedef int(* logWriteFunction_t) (void *context, uint16_t channelLevel, const char *msg, int msgLength)

Type of the function that does the actual writing on a trace channel.

Parameters

context	The same `context` variable that is passed as parameter to logSetChannels()
channelLevel	Channel and level that triggered this trace
msg	Data to write.
msgLength	Length, in bytes, of `msg`.

Returns: Zero on success, non-zero on error.

Enumeration Type Documentation

enum logLevel_t

General tracing levels.

Applications may define intermediary values.

Enumerator
LOG_DEBUG	Lowest-priority: only for debugging.
LOG_INFO	Informative.
LOG_WARNING	Run-time warnings.
LOG_ERROR	Run-time errors.
LOG_CRITICAL	Critical.
LOG_ALWAYS	Always write (if channel is enabled)

enum logReservedChannels_t

List of reserved log channels.

These channels are reserved by larlib and other system libraries.

Enumerator
LOG_CH_BASE	Basic Definitions and LOG_ASSERT()
LOG_CH_CONV	Conversion routines
LOG_CH_DATE	Date and time
LOG_CH_FS	File System
LOG_CH_INI	INI file parsing
LOG_CH_MEM	Memory Management
LOG_CH_TAB	Table Management
LOG_CH_STEP	State-machine
LOG_CH_FORMAT	Buffer formatting
LOG_CH_TASK	Multi-threading

Function Documentation

int logChannelIsEnabled ( uint16_t channelLevel )

Check if a log channel is enabled for a specific priority level.

Given a channelLevel, formatted exactly as would for logPrintf() or logDump(), check if a write to this configuration would generate a trace.

Parameters

channelLevel Defines both the channel and the level of this trace. The lower 8-bits define the channel to use, and the upper 8-bits define the level.

Returns: Non-zero if a logPrintf() or logDump() to channelLevel would generate a call to the configured writeFunction.; Zero otherwise.

int logDump	(	uint16_t	channelLevel,
		const void *	buffer,
		int	size
	)

Write a block of data as a binary dump.

The output format should include both the readable part of the data pointed by buffer and the hexadecimal of its bytes.

Parameters

channelLevel	Channel and level of this trace (see logPrintf())
buffer	Data block to dump.
size	Number of bytes of `buffer` to print.

Returns: BASE_ERR_OK

See also: logSetChannels

int logDumpFormattedAscii	(	logWriteFunction_t	write,
		void *	context,
		uint16_t	channelLevel,
		const void *	data,
		int	dataLen
	)

dumpFormatFunction that formats the received buffer as a two-column hexadecimal and ASCII display and calls the received write function.

This function can be used as the dumpFormatFunction parameter of logSetChannels() for channels where write is not ready to directly receive binary (non-ASCII) data.

Parameters

write	Function that will be used to actually write the formatted lines.
context	Ignored and passed as received to `write`.
channelLevel	Channel and level that triggered this trace
data	Binary data to format.
dataLen	Length of `data` in bytes.

Returns: The return of write.

int logPrintf	(	uint16_t	channelLevel,
		const char *	fmt,
			...
	)

sprintf() like formatted traces.

This call formats and sends the message defined by fmt using the parameters associated with the channel and priorities defined in channelLevel.

The values in logLevel_t are defined such that a simple OR'ing of the values with the channel number work.

For example, to write to channel 42 with the default priority:

1 logPrintf(42, "this is the message %d", 1);

And to write to the same channel using the LOG_CRITICAL priority:

1 logPrintf(42|LOG_CRITICAL, "this is the message %d", 2);

Parameters

channelLevel	Defines both the channel and the level of this trace. The lower 8-bits define the channel to use, and the upper 8-bits define the level.
fmt	String format (as `sprintf()`).

Returns: BASE_ERR_OK even if channel is disabled or message not written by priority; An error code returned by the writeFunction defined for this channel

See also: logSetChannels

int logPrintvf	(	uint16_t	channelLevel,
		const char *	fmt,
		va_list	va
	)

A version of logPrintf() that accepts a va_list as parameter.

This is quite useful for creating other abstractions on top of this lib.

Parameters

channelLevel	Channel and level of tracing for this trace (see logPrintf()).
fmt	String format (as `sprintf()`).
va	`va_list` with the list of parameters to be formatted.

Returns: BASE_ERR_OK

See also: logSetChannels

int logSetChannels	(	uint8_t	firstChannel,
		int	numChannels,
		uint16_t	level,
		logWriteFunction_t	writeFunction,
		logDumpFunction_t	dumpFormatFunction,
		void *	context
	)

Configures one or more tracing channels.

Configures the first numChannels starting at firstChannel to use the tracing priority level and write output using writeFunction and dumpFormatFunction.

For example, to configure the channels in the range [5,10]:

1 logSetChannels(5, 5, myLevel, myWriteFunction, NULL, myContext);

To configure all channels, use the macro LOG_ALL_CHANNELS:

1 logSetChannels(LOG_ALL_CHANNELS, myLevel, myWriteFunction, NULL, myContext);

Parameters

firstChannel	Index of the first channel to configure.
numChannels	How many channels starting at `firstChannel` to configure. If zero no channels are configured!
level	Tracing level enabled for the selected channels. Only the most significant 8-bits are used, see the values in logLevel_t.
writeFunction	A function that is called with the string to write. It is called only with a zero-terminated string of chars in the ASCII range. Using `NULL` disables this channel.
dumpFormatFunction	A function that is called to pre-process the binary buffer received by logDump(). If `NULL` then logDump() will directly call `writeFunction` with the received data buffer. If not `NULL` then this function should format the input buffer and call the received `write` function with the formatted output. See logDumpFormattedAscii().
context	This value is stored and passed unchanged to `writeFunction`, and can be used to configure its behavior. See the documentation of each logWrite function for more information.

Returns: BASE_ERR_OK; BASE_ERR_INVALID_PARAMETER if the range defined by firstChannel and numChannels is invalid

See also: logWriteFunction_t; logDumpFunction_t; logPrintf; logPrintvf; logDump; logDumpFormattedAscii; logWriteTeliumTrace

int logWriteTeliumRemoteDebugger	(	void *	context,
		uint16_t	channelLevel,
		const char *	msg,
		int	msgLength
	)

A logWriteFunction_t that can be used as parameter to logSetChannels() and writes traces to the Remote Debugger console on IngeDev.

Attention: This function is Telium-specific and may not be defined on other platforms.

Parameters

context	Not used
channelLevel	Channel and level that triggered this trace
msg	Zero-terminated string to write.
msgLength	Length of `msg` in bytes.

Returns: Always return BASE_ERR_OK.

See also: logSetChannels

int logWriteTeliumTrace	(	void *	context,
		uint16_t	channelLevel,
		const char *	msg,
		int	msgLength
	)

A logWriteFunction_t that can be used as parameter to logSetChannels() and writes traces using Telium's trace() function.

Traces are written using the SAP code defined by the integer value of context. For example, to use SAP code 0xB000, use:

1 logWriteTeliumTrace((void*) 0xB000, myMessage, strlen(myMessage))

To configure the channel 42 to use this tracing function with SAP code 0x1234, use:

1 logSetChannels(42, 1, LOG_DEBUG, logWriteTeliumTrace, NULL, (void*) 0x1234);

Attention: This function is Telium-specific and may not be defined on other platforms.

Parameters

context	The value of this pointer indicates which SAP code to use.
channelLevel	Channel and level that triggered this trace
msg	Zero-terminated string to write.
msgLength	Length of `msg` in bytes.

Returns: Always return BASE_ERR_OK.

See also: logSetChannels

LAR Library: Logging

LAR Library

Macros

Typedefs

Enumerations

Functions

Detailed Description

Rationale

Introduction

Setup

Telium

Tracing

Macro Definition Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation

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