C/C++ Logging Library (Clog)

Clog is Blender's own logging library, located in intern/clog/. Logging can be enabled by starting Blender with the --log command line options. Refer to the User Manual for more options to control the logging via command line arguments.

Usage

• CLG_LOGREF_DECLARE_GLOBAL macro to declare CLG_LogRef pointers.
• CLOG_ prefixed macros for logging.

Identifiers

CLG_LogRef holds an identifier which defines the category of the logger. You can define and use identifiers as needed, logging will lazily initialize them. By convention lower case dot separated identifiers are used, eg: module.sub_module, this allows filtering by module.*, see CLG_type_filter_include, CLG_type_filter_exclude.

There is currently no functionality to remove a category once it's created.

Severity

• INFO: Simply log events, uses verbosity levels to control how much information to show.
• WARN: General warnings (which aren't necessary to show to users).
• ERROR: An error we can recover from, should not happen.
• FATAL: Similar to assert. This logs the message, then a stack trace and abort.

Verbosity Level

Usage:

Level	Description
0	Always show (used for warnings, errors). Should never get in the way or become annoying.
1	Top level module actions (eg: load a file, create a new window .. etc).
2	Actions within a module (steps which compose an action, but don't flood output). Running a tool, full data recalculation.
3	Detailed actions which may be of interest when debugging internal logic of a module. These may flood the log with details.
4+	May be used for more details than 3, should be avoided but not prevented.