diff --git a/components/log/README.rst b/components/log/README.rst index 03ca5f0da..e6061bcb1 100644 --- a/components/log/README.rst +++ b/components/log/README.rst @@ -4,26 +4,34 @@ Logging library Overview -------- -Log library has two ways of managing log verbosity: compile time, set via menuconfig; and runtime, using :cpp:func:`esp_log_level_set` function. +The logging library provides two ways for setting log verbosity: -The log levels are Error, Warning, Info, Debug, and Verbose (from lowest to highest level of verbosity). +- **At compile time**: in menuconfig, set the verbosity level using the option :envvar:`CONFIG_LOG_DEFAULT_LEVEL`. All logging statements for verbosity levels higher than :envvar:`CONFIG_LOG_DEFAULT_LEVEL` will be removed by the preprocessor. +- **At runtime**: all logs for verbosity levels lower than :envvar:`CONFIG_LOG_DEFAULT_LEVEL` are enabled by default. The function :cpp:func:`esp_log_level_set` can be used to set a logging level on a per module basis. Modules are identified by their tags, which are human-readable ASCII zero-terminated strings. -At compile time, filtering is done using :envvar:`CONFIG_LOG_DEFAULT_LEVEL` option, set via menuconfig. All logging statements for levels higher than :envvar:`CONFIG_LOG_DEFAULT_LEVEL` will be removed by the preprocessor. +There are the following verbosity levels: -At run time, all logs below :envvar:`CONFIG_LOG_DEFAULT_LEVEL` are enabled by default. :cpp:func:`esp_log_level_set` function may be used to reduce logging level per module. Modules are identified by their tags, which are human-readable ASCII zero-terminated strings. +- Error (lowest) +- Warning +- Info +- Debug +- Verbose (highest) + +.. note:: + + The function :cpp:func:`esp_log_level_set` cannot set logging levels higher than specified by :envvar:`CONFIG_LOG_DEFAULT_LEVEL`. To increase log level for a specific file at compile time, use the macro `LOG_LOCAL_LEVEL` (see the details below). -Note that :cpp:func:`esp_log_level_set` can not increase logging level beyound that set by :envvar:`CONFIG_LOG_DEFAULT_LEVEL`. To increase log level for a specific file at compile time, `LOG_LOCAL_LEVEL` macro can be used (see below for details). How to use this library ----------------------- -In each C file which uses logging functionality, define TAG variable like this: +In each C file that uses logging functionality, define the TAG variable as shown below: .. code-block:: c static const char* TAG = "MyModule"; -then use one of logging macros to produce output, e.g: +Then use one of logging macros to produce output, e.g: .. code-block:: c @@ -37,23 +45,24 @@ Several macros are available for different verbosity levels: * ``ESP_LOGD`` - debug * ``ESP_LOGV`` - verbose (highest) -Additionally there is an ``_EARLY`` variant for each of these macros (e.g. :c:macro:`ESP_EARLY_LOGE`). These variants can run in startup code, before heap allocator and syscalls have been initialized. When compiling bootloader, normal ``ESP_LOGx`` macros fall back to the same implementation as ``ESP_EARLY_LOGx`` macros. So the only place where ``ESP_EARLY_LOGx`` have to be used explicitly is the early startup code, such as heap allocator initialization code. +Additionally, there are ``ESP_EARLY_LOGx`` versions for each of these macros, e.g., :c:macro:`ESP_EARLY_LOGE`. These versions have to be used explicitly in the early startup code only, before heap allocator and syscalls have been initialized. Normal ``ESP_LOGx`` macros can also be used while compiling the bootloader, but they will fall back to the same implementation as ``ESP_EARLY_LOGx`` macros. -To override default verbosity level at file or component scope, define ``LOG_LOCAL_LEVEL`` macro. At file scope, define it before including ``esp_log.h``, e.g.: +To override default verbosity level at file or component scope, define the ``LOG_LOCAL_LEVEL`` macro. + +At file scope, define it before including ``esp_log.h``, e.g.: .. code-block:: c #define LOG_LOCAL_LEVEL ESP_LOG_VERBOSE #include "esp_log.h" - -At component scope, define it in component makefile: +At component scope, define it in the component makefile: .. code-block:: make CFLAGS += -D LOG_LOCAL_LEVEL=ESP_LOG_DEBUG -To configure logging output per module at runtime, add calls to :cpp:func:`esp_log_level_set` function: +To configure logging output per module at runtime, add calls to the function :cpp:func:`esp_log_level_set` as follows: .. code-block:: c @@ -64,5 +73,5 @@ To configure logging output per module at runtime, add calls to :cpp:func:`esp_l Logging to Host via JTAG ^^^^^^^^^^^^^^^^^^^^^^^^ -By default logging library uses vprintf-like function to write formatted output to dedicated UART. By calling a simple API, all log output may be routed to JTAG instead, making logging several times faster. For details please refer to section :ref:`app_trace-logging-to-host`. +By default, the logging library uses the vprintf-like function to write formatted output to the dedicated UART. By calling a simple API, all log output may be routed to JTAG instead, making logging several times faster. For details, please refer to Section :ref:`app_trace-logging-to-host`. diff --git a/docs/en/api-reference/system/index.rst b/docs/en/api-reference/system/index.rst index a02f74aa6..2abc62960 100644 --- a/docs/en/api-reference/system/index.rst +++ b/docs/en/api-reference/system/index.rst @@ -26,4 +26,4 @@ System API Miscellaneous System APIs -Example code for this API section is provided in :example:`system` directory of ESP-IDF examples. +Code examples for this API section are provided in the :example:`system` directory of ESP-IDF examples. diff --git a/docs/en/api-reference/system/log.rst b/docs/en/api-reference/system/log.rst index bcfe0f542..72609c69a 100644 --- a/docs/en/api-reference/system/log.rst +++ b/docs/en/api-reference/system/log.rst @@ -3,11 +3,11 @@ Application Example ------------------- -Log library is commonly used by most of esp-idf components and examples. For demonstration of log functionality check :idf:`examples` folder of `espressif/esp-idf `_ repository, that among others, contains the following examples: +The logging library is commonly used by most esp-idf components and examples. For demonstration of log functionality, check ESP-IDF's :idf:`examples` directory. The most revelant examples that deal with logging are the following: -* :example:`system/ota` -* :example:`storage/sd_card` -* :example:`protocols/https_request` +* :example:`system/ota` +* :example:`storage/sd_card` +* :example:`protocols/https_request` API Reference -------------