Defines
Logging facilities
BeRTOS core functionality

Logging system module. More...

Defines

#define LOG_ERR(str,...)   LOG_PRINT("ERR", str, ## __VA_ARGS__)
 Output an error message.
#define LOG_ERRB(x)   x
 Define a code block that will be compiled only when LOG_LEVEL >= LOG_LVL_ERR.
#define LOG_WARN(str,...)   LOG_PRINT("WARN", str, ## __VA_ARGS__)
 Output a warning message.
#define LOG_WARNB(x)   x
 Define a code block that will be compiled only when LOG_LEVEL >= LOG_LVL_WARN.
#define LOG_INFO(str,...)   LOG_PRINT("INFO", str, ## __VA_ARGS__)
 Output an informative message.
#define LOG_INFOB(x)   x
 Define a code block that will be compiled only when LOG_LEVEL >= LOG_LVL_INFO.

Logging level definition

When you choose a log level messages you choose also which print function are linked.

When using a log level, you link all log functions that have a priority higher or equal than the level you chose. The priority level go from error (highest) to info (lowest).

#define LOG_LVL_NONE   0
#define LOG_LVL_ERR   1
#define LOG_LVL_WARN   2
#define LOG_LVL_INFO   3

Logging format

There are two logging format: terse and verbose.

The latter prepends function names and line number information to each log entry.

#define LOG_FMT_VERBOSE   1
#define LOG_FMT_TERSE   0

Detailed Description

Logging system module.

This module implement a simple interface to use the multi level logging system. The log message have the priority order, like this:

  • error message (highest)
  • warning message
  • info message (lowest)

With this priority system we log only the messages that have priority higher or equal to the log level that has been configurated; messages below the selected log level are not included at compile time, so no time and space is wasted on unused functions.

Furthermore you can define different log levels for each module. To do this you just need to define LOG_LEVEL in the configuration file for the selected module.

This module provides two types of macros:

  • LOG_* macros: these macros allow formatted output, using the same format as kprintf
  • LOG_*B macros: these macros allow to optionally compile a block of code depending on the logging level chosen

To use the logging system you should include this module in your driver and use one of the LOG_ERR, LOG_WARN and LOG_INFO macros to output error messages. Then you should define a LOG_LEVEL and LOG_VERBOSE costant in your cfg/cfg_<your_cfg_module_name>.h using the follow policy:

  • in your file cfg/cfg_<cfg_module_name>.h, define the logging level and verbosity mode for your specific module:
    #define <cfg_module_name>_LOG_LEVEL    LOG_LVL_INFO

    #define <cfg_module_name>_LOG_FORMAT   LOG_FMT_VERBOSE
  • then, in the module where you use the logging macros you should define the macros LOG_LEVEL and LOG_FORMAT and you should include cfg/log.h module, as demonstrated in the following example:
    // Define log settings for cfg/log.h.
    #define LOG_LEVEL   <cfg_module_name>_LOG_LEVEL
    #define LOG_FORMAT  <cfg_module_name>_LOG_FORMAT
    #include <cfg/log.h>

if you include a log.h module without defining the LOG_LEVEL and LOG_VERBOSE macros, the module uses the default settings.

WARNING: when using the log.h module make sure to include this module after a cfg_<cfg_module_name>.h, because the LOG_LEVEL and LOG_VERBOSE macros must be defined before including the log module. Otherwise the log module will use the default settings.

Author:
Daniele Basile <asterix@develer.com>