lib_logging: Debug Printing£££doc/rst/lib_logging.html#lib-logging-debug-printing

lib_logging: Debug Printing$$$Introduction£££doc/rst/lib_logging.html#introduction

This library provides a lightweight printf function that can be enabled or disabled via configuration defines. Code can be declared to be within a “debug unit” (usually a library or application source base) and prints can be enabled/disabled per debug unit.

lib_logging is intended to be used with the XCommon CMake , the XMOS application build and dependency management system.

lib_logging: Debug Printing$$$API£££doc/rst/lib_logging.html#api

To use this module, include lib_logging in the application’s APP_DEPENDENT_MODULES list and include the debug_print.h header file.

void debug_printf(char fmt[], ...)

A limited functionality version of printf that is low memory.

This function works like C-standard printf except that it only accepts d, x, s, u and c format specifiers with no conversions.

The p format specifier is treated the same as a x.

The capital version of each format specifier performs the same as the lower case equivalent.

Any alignment or padding characters are simply ignored.

The function uses the functions from print.h to do the underlying printing.

Unlike printf this function has no return value.

Whether the function does any output can be controlled via defines such as DEBUG_PRINT_ENABLE or DEBUG_PRINT_ENABLE_[debug unit name] in the application’s debug_conf.h

lib_logging: Debug Printing$$$Debug units£££doc/rst/lib_logging.html#debug-units

A source file can be added to a debug unit by defining the DEBUG_UNIT macro before inclusion of debug_print.h. For example:

#define DEBUG_UNIT ETHERNET_MODULE
#include "debug_print.h"

To include all source files in a module in a particular debug unit, it is convenient to do it in the lib_build_info.cmake file of the module e.g.:

set(LIB_COMPILER_FLAGS ... -DDEBUG_UNIT=ETHERNET_MODULE ...)

If no DEBUG_UNIT is defined then the default debug unit is APPLICATION.

lib_logging: Debug Printing$$$Enabling printing£££doc/rst/lib_logging.html#enabling-printing

By default, debug printing is turned off. To enable printing you need to pass the correct command line option to compilation. The following defines can be set by using the -D option to the compiler. For example, the following in your application CMakeLists.txt will enable debug printing:

set(APP_COMPILER_FLAGS ... -DDEBUG_PRINT_ENABLE=1 ...)

The following defines can be set:

DEBUG_PRINT_ENABLE

Setting this define to 1 or 0 will control whether debug prints are output.

DEBUG_PRINT_ENABLE_[debug unit]

Enabling this define will cause printing to be enabled for a specific debug unit. If set to 1, this will override the default set by DEBUG_PRINT_ENABLE.

DEBUG_PRINT_DISABLE_[debug unit]

Enabling this define will cause printing to be disabled for a specific debug unit. If set to 1, this will override the default set by DEBUG_PRINT_ENABLE.