/**
@page logging Logging Infrastructure
@brief This page contains an overview of the logging infrastructure used by the C-SDK Libraries.

<p>
The C-SDK libraries utilize one of the following 4 logging macro interfaces, each with a different verbosity level:
- `LogError` for **Error** level
- `LogWarn` for **Warning** level
- `LogInfo` for **Info** level
- `LogDebug` for **Debug** level

@note By default, each library contains empty definitions for the above logging macros, thereby generating no code for logging calls.

To enable logging within the libraries, your application should implement these macros through the library-specific config file (for example, the `core_mqtt_config.h` file for MQTT library).
The implementation of these macros can be provided as a mapping to the your platform-specific logging framework.
</p>

@section design Design Architecture
@brief The logging infrastructure architecture follows a dependency inversion design principle of allowing your application to inject an implementation of logging interface macros through the library-specific config file (like `core_mqtt_config.h`).

@image html logging_architecture.png width=40%

@section reference_implementation Reference Implementation
@brief For reference example of a POSIX-specific logging implementation, refer to the [demos/logging-stack](https://github.com/aws/aws-iot-device-sdk-embedded-C/tree/main/demos/logging-stack) folder from the root directory of the C-SDK repository.

The @ref logging_stack.h file contains the definition of all the logging interface macros (`LogError`, `LogWarn`, `LogInfo`, `LogDebug`) that eventually map to the standard C function, `printf`.

The file contains the following features:
- Ability to define **logging verbosity level** for a library through the #LIBRARY_LOG_LEVEL macro. (All the logging levels are defined in @ref logging_levels.h). This allows logging macros to be conditionally enabled depending on the configured logging level. For example, for the `LOG_INFO` verbosity configuration, only the `LogError`, `LogWarn`, `LogInfo` macros are enabled but the `LogDebug` macro is disabled.
- With the above ability, the compiler does not generate code for library logging calls to disabled logging macros. For example, a `LOG_ERROR` verbosity configuration does not generate code for logging calls for the `LogWarn`, `LogInfo`, or `LogDebug` macros, ONLY for `LogError` macro.
- Ability to set the **library name** as metadata in library logs through the #LIBRARY_LOG_NAME macro.
- Ability to add **metadata** as a prefix in log messages through the #LOG_METADATA_ARGS and #LOG_METADATA_FORMAT macros. By default, it adds the metadata of the format:`[<Logging-Level>] [<Library-Name>] [<File-Name>:<Line-Number>]`. Here is an example snippet of log messages from the [MQTT Basic TLS demo](https://github.com/aws/aws-iot-device-sdk-embedded-C/tree/main/demos/mqtt/mqtt_demo_basic_tls):
@code{sh}
[INFO] [MQTT] [core_mqtt.c:854] Packet received. ReceivedBytes=2.
[INFO] [MQTT] [core_mqtt_serializer.c:969] CONNACK session present bit not set.
[INFO] [MQTT] [core_mqtt_serializer.c:911] Connection accepted.
[INFO] [MQTT] [core_mqtt.c:1525] Received MQTT CONNACK successfully from broker.
[INFO] [MQTT] [core_mqtt.c:1791] MQTT connection established with the broker.
@endcode

For an example of how the demo projects utilize the logging stack, refer to any `core_mqtt_config.h` file in the [MQTT demos folder](https://github.com/aws/aws-iot-device-sdk-embedded-C/tree/main/demos/mqtt) of the C-SDK repository.

*/