log.h File Reference

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Detailed Description

A logger object will format and write a text message to the associated file descriptor subject to logging constraints/options that can be changed dynamically during runtime. Logger objects may be chained together, when any member of this chain is passed to aw_log() all logger objects in the chain are evaluated. This is especially useful when you want to log different messages to different file descriptors (e.g., All messages to a master log file, errors to an fd that has an SNMP process listening to send traps to a monitoring system, security warnings to an fd that has an active security watchdog running).

Logging constraints are based a notion of a 'level range'. Each logger has a high level and a low level. Any messages with a level within (inclusive) the level range of the logger being evaluated will be logged to the assocated fd.

Logger objects may (optionally) have another logger object (and chain) associated to handle IO errors. If this object is NULL and AW_LOGGER_ERR2SYSLOG or AW_LOGGER_ERR2STDERR are set, then IO error messages will go to syslog and stderr, respectively.

Note: By passing a negative fd and enabling AW_LOGGER_DUP2SYSLOG you get basic syslog logging only (writes are skipped for negative fds with no error generated).

Options are listed in aw_logger_flag_t.

This library is NOT thread safe, however, the aw_log() function IS thread safe.

#include "sys.h"
#include "thread.h"
#include "errors.h"
#include "util.h"

Go to the source code of this file.

Data Structures
struct	aw_logger_params_t
struct	aw_logger_struct
Defines
#define	AW_LOGGER_DEFAULT_FLAGS
	Macro with the default flags settings to pass to aw_logger_init().
#define	AW_LOGGER_IS_ROTATING(flags)   ( (flags)&(AW_LOGGER_ROTATE_HR | AW_LOGGER_ROTATE_DY | AW_LOGGER_ROTATE_MH) )
	Macro to test if doing rotation.
Typedefs
typedef aw_logger_struct	aw_logger_t
Enumerations
enum	aw_logger_flag_t {   AW_LOGGER_ENABLED = 0x1, AW_LOGGER_CACHEMSG = 0x2, AW_LOGGER_ERR2SYSLOG = 0x4, AW_LOGGER_ERR2STDERR = 0x8,   AW_LOGGER_PREPEND_DATE = 0x10, AW_LOGGER_DUP2SYSLOG = 0x20, AW_LOGGER_DUP2STDERR = 0x40, AW_LOGGER_APPEND_NEWLINE = 0x80,   AW_LOGGER_ROTATE_HR = 0x100, AW_LOGGER_ROTATE_DY = 0x200, AW_LOGGER_ROTATE_MH = 0x400, AW_LOGGER_DEDUP = 0x800,   AW_LOGGER_NBITS }
	Bit position indicates capability. More...
Functions
int32_t	aw_log (aw_logger_t *logger, int32_t level, const char *fmt,...) __attribute__((format(printf
	Write a message on an aw_logger_t.
int32_t	aw_logger_clear (aw_logger_t *logger)
	Free any resources allocated and referenced by logger.
void	aw_logger_disable (aw_logger_t *logger)
	Unset enable bit, update chain.
void	aw_logger_enable (aw_logger_t *logger)
	Set enable bit, update chain.
int32_t	aw_logger_init (aw_logger_t *logger, aw_logger_params_t *params)
	Initialize an aw_logger_t.
int32_t	aw_logger_link (aw_logger_t *logger, aw_logger_t *chain)
	Link logger into loggin chain, update chain.
void	aw_logger_setflags (aw_logger_t *logger, aw_logger_flag_t new_flags)
	Overwrite flags, update chain.
void	aw_logger_unlink (aw_logger_t *logger)
	Unlink logger, update chain.

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Define Documentation

#define AW_LOGGER_DEFAULT_FLAGS

Value: (\ AW_LOGGER_ENABLED | \ AW_LOGGER_CACHEMSG | \ AW_LOGGER_ERR2SYSLOG | \ AW_LOGGER_ERR2STDERR | \ AW_LOGGER_PREPEND_DATE | \ AW_LOGGER_APPEND_NEWLINE \ ) Macro with the default flags settings to pass to aw_logger_init().

#define AW_LOGGER_IS_ROTATING (  flags   )     ( (flags)&(AW_LOGGER_ROTATE_HR | AW_LOGGER_ROTATE_DY | AW_LOGGER_ROTATE_MH) )

Macro to test if doing rotation.

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Typedef Documentation

typedef struct aw_logger_struct aw_logger_t

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Enumeration Type Documentation

enum aw_logger_flag_t

Bit position indicates capability. Enumeration values: AW_LOGGER_ENABLED  AW_LOGGER_CACHEMSG  AW_LOGGER_ERR2SYSLOG  AW_LOGGER_ERR2STDERR  AW_LOGGER_PREPEND_DATE  AW_LOGGER_DUP2SYSLOG  AW_LOGGER_DUP2STDERR  AW_LOGGER_APPEND_NEWLINE  AW_LOGGER_ROTATE_HR  AW_LOGGER_ROTATE_DY  AW_LOGGER_ROTATE_MH  AW_LOGGER_DEDUP  AW_LOGGER_NBITS

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Function Documentation

int32_t aw_log (  aw_logger_t *  logger, int32_t  level, const char *  fmt, ...  )

Write a message on an aw_logger_t. aw_log Parameters: logger  The logger object (may be NULL, in which case this is a noop) level  Level of log message fmt  Format string (see fprintf) ...  Argument list for format string (ala fprintf) Returns: Returns 0 on success, AW_LOGWRITE_ERROR,AW_OUTOFMEMORY_ERROR on error

int32_t aw_logger_clear (  aw_logger_t *  logger  )

Free any resources allocated and referenced by logger. aw_logger_clear Parameters: logger  The logger object Returns: Returns 0

void aw_logger_disable (  aw_logger_t *  logger  )

Unset enable bit, update chain. aw_logger_disable Parameters: logger  Logger to disable

void aw_logger_enable (  aw_logger_t *  logger  )

Set enable bit, update chain. aw_logger_enable Parameters: logger  Logger to enable

int32_t aw_logger_init (  aw_logger_t *  logger, aw_logger_params_t *  params )

Initialize an aw_logger_t. aw_logger_init Parameters: logger  The logger object params  The params Returns: Returns 0

int32_t aw_logger_link (  aw_logger_t *  logger, aw_logger_t *  chain )

Link logger into loggin chain, update chain. aw_logger_link Parameters: logger  Logger to link chain  Chain of loggers (can be NULL) Returns: Return 0 on success, AW_LOGGER_CHAIN_INSERT_ERROR on failure

void aw_logger_setflags (  aw_logger_t *  logger, aw_logger_flag_t  new_flags )

Overwrite flags, update chain. aw_logger_setflags Parameters: logger  Logger to set new_flags  New flags for logger

void aw_logger_unlink (  aw_logger_t *  logger  )

Unlink logger, update chain. aw_logger_unlink Parameters: logger  Logger to unlink

Aware 0.11.1 Copyright (C) 1998-2005 Russell Leighton (russ@elegant-software.com)