NAME

       log_open, log_close, log_reset, log_flush, log_printf, log_vprintf, log_putc, log_puts - log routines for
       debugging

LIBRARIES

       Debug Library (-ldebug)

SYNOPSIS

       #include <debug/log.h>

       int log_open(const char *logfile, int level, int flags);
       void log_close(void);
       int log_reset(void);
       int log_flush(void);
       int log_printf(int level, const char *fmt, ...);
       int log_vprintf(int level, const char *fmt, va_list ap);
       int log_putc(int level, int c);
       int log_puts(int level, const char *str);

DESCRIPTION

       log_open() initializes the logging system. The filename of the file to which messages are  logged  should
       be  specified  by logfile, or NULL if messages should be printed to the console. The values for level and
       flags are given in the next section.

       From version 0.4.1 onwards the debug library also supports logging to syslog instead of a  file.  Instead
       of  specifying  a  file,  just specify a string in the form ident.facility, where ident is a string which
       will be prepended to each syslog message and is usually the program name.  The  facility  should  be  the
       facility to which messages should be logged.

       log_close() flushes all pending messages, and closes the file descriptor of the log file (if any).

       log_reset()  reinitializes  the logging system. If any files are currently opened for writing, it will be
       closed and reopened. This is useful if you need to rotate log files.

       log_flush() flushes all pending messages (if any).

       log_printf() and log_vprintf() are replacements for printf(3) and vprintf(3) respectively.

       log_putc() will log a single character. This is the equivalent of putchar(3).

       log_puts() will log a string. It is the equivalent of puts(3), except that is does not append a  trailing
       newline.

PARAMETERS

       This section lists the parameters used to set the values of level and flags.

   level
       This determines the importance of the message. The levels are, in order of decreasing verbosity:

       LOG_NOISY
              verbose debug messages

       LOG_DEBUG
              debug messages

       LOG_VERBOSE
              informational messages

       LOG_NORMAL
              normal, but significant, conditions

       LOG_WARNING
              warning conditions

       LOG_ERROR
              error conditions

       LOG_QUIET
              no messages are printed

       The  level argument to log_printf(), log_vprintf(), log_putc(), and log_puts() specify the level at which
       the message should be printed. It does not make sense to specify LOG_QUIET to these functions.

       The level argument to log_open() sets the verbosity of the program. Any messages  printed  with  a  level
       higher (more verbose) than that specified to the log_open() function, will be discarded.

   flags
       The flags argument to log_open() is an OR of any of these:

       LOG_HAVE_COLORS
              If this flag is specified and messages are printed to the console (i.e. no log file is specified),
              messages will be printed in different colors, depending on their log level.

       LOG_PRINT_FUNCTION
              If this flag is specified, the function in which the print function was called would be printed in
              addition to the filename and line number.

       LOG_DEBUG_PREFIX_ONLY
              If this flag is specified, only messages with a level higher or equal to (i.e. more or as verbose)
              LOG_DEBUG will be printed in color and with file, line number, and (if necessary), the function.

       LOG_DETECT_DUPLICATES
              If this flag is specified, messages would be buffered and duplicate lines would  not  be  printed.
              Instead, the first message would be printed, followed by a line describing the number of times the
              message repeated. This is a great way to prevent flooding,  but  unfortunately  it  has  the  side
              effect of always being one statement behind.

       LOG_DETECT_FLOODING
              If  specified, the rate at which messages are printed would be limited in order to avoid flooding.
              This feature have not been implemented yet, and is currently ignored.

RETURN VALUE

       All functions except log_close() return 0 if successful, -1 if some error occurred. Check  errno  to  see
       which error occurred.

       If  log_reset()  or  log_open() fails, behaviour is undefined and it should be assumed that no logging is
       possible.

       The log_close() function returns no value.

NOTES

       If this routines are combined with the memory routines, care should be  taken  to  call  open  and  close
       functions in the right order. The correct order is as follows:

              mem_open (NULL);
              log_open (NULL,LOG_NORMAL,LOG_HAVE_COLORS | LOG_PRINT_FUNCTION);
              atexit (mem_close);
              atexit (log_close);

       Of course, atexit(3) should only be used if the program will not forked.

       None  of  the  libdebug  routines  are  thread-safe.  I'm  not  planning  to change this either! For more
       information, please see http://threading.2038bug.com/

SEE ALSO

       mem_open(3), errno(3), atexit(3), printf(3), vprintf(3), putchar(3), puts(3)
       logrotate(8), syslog(3), logger(1)

AUTHOR

       Written by Abraham vd Merwe <abz@blio.com>