About lxUtils

These files contain C++14 utilities for:

• template-based sprintf() formatting à la Bjarne Stroustrup "A Type-Safe printf", see "The C++ Programming Language", 4th edition, section 28.6.1 (page 809)
• free-form log tags (instead of levels) with compile-time string hashing from Dan Bernstein

The logger is somewhat similar to boost::format but uses the traditional printf() format flags and log levels don't need to be hierarchical; they're a set of freeform tags that can be ANDed, ORed, etc. (like in std::unordered_set).

Log tags are computed at compile-time in constexpr functions, so don't need to be pre-declared (in an enum, say), can be used in any source file / translation unit, without worrying about initialization order (static-, thread_local- or otherwise). Logs can be triggered from secondary threads, possibly from within destructors.

Overview

#include "lx/ulog.h"

using namespace LX;

void	resized() override
{
	uLog("UI"_log, "resized %s to %d x %d", getName(), getWidth(), getHeight());
}

constexpr auto	LIFETIME = "APP_DTOR"_log;

void	shutdown() override
{
	uLog(LIFETIME, "App::shutdown()");
}

	JUCEApplicationImp::~JUCEApplicationImp()
{
	uLog(DTOR, "App::DTOR");
}

Headers

• ulog.h - logger interfaces
• xstring.h - sprintf-formatter
• xutils.h - timestamps & misc
• color.h - RGB color definitions for the UI (optional)

Within these headers, declarations happen within their own namespace LX. Any local synonyms to STL types are #used individually (not in bulk) within the LX namespace, i.e. without polluting the global namespace (see Stroustrup "The C++ Programming Language", 4th ed, Section 14.2.2: "#using declarations").

Examples

There are UI integration examples for JUCE and wxWidgets, respectively. The single-source app generates logs from different threads, displays them in color, and dynamically toggles filtering. A file log target is also created upstream.

Binaries build for Clang/libc++ and g++ 4.9.1 with libstdc++, either with CMake or the CodeLite IDE.

Build Configuration

• path to JUCE source code (e.g. ~/development/git/JUCE)

  $(JUCE_DIR)

• to support juce::String, juce::Colour

  #define LX_JUCE 1

• for wxWidgets, make sure wx-config is $PATH-accessible as usual

• to support wxString, wxColour

  #define LX_WX 1

• to enable off-thread log generation in main.cpp

  #define LOG_FROM_ASYNC 1

Building with CMake

Building for JUCE with Clang and libc++

mkdir build && cd build
cmake -DLX_JUCE=1 -DJUCE_DIR="$PWD../../../git/JUCE" -DCMAKE_CXX_COMPILER=/usr/bin/clang++ -DCMAKE_CXX_FLAGS="-stdlib=libc++" -DCMAKE_MODULE_LINKER_FLAGS="-stdlib=libc++" ..
make

Building for wxWidgets with Clang and libc++

mkdir build && cd build
cmake -DLX_WX=1 -DCMAKE_CXX_COMPILER=/usr/bin/clang++ -DCMAKE_CXX_FLAGS="-stdlib=libc++" -DCMAKE_MODULE_LINKER_FLAGS="-stdlib=libc++" ..
make

or something like

mkdir build && cd build
export WXDIR="$LXBUILD/wx_dbg_libcxx" && cmake -DLX_WX=1 -DCMAKE_CXX_COMPILER=/usr/bin/clang++ -DCMAKE_CXX_FLAGS="-stdlib=libc++" -DCMAKE_MODULE_LINKER_FLAGS="-stdlib=libc++" ..
make

Misc

• I started writing these for a language-teaching software called "Linguamix", which is where the "lx"-prefix came from.
• source code is formatted with 8-char tabs, not spaces. So there.
• source files inevitably end wih the comment
  // nada mas
  ever since I used a macro-assembler that wouldn't flush the disk cache correctly, so on crash my source files would be missing a sector's worth of data.
• swearwords usually come more naturally to me in French.