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After much research and digging into the Boost libraries documentation, I cannot find answers or high-level advice on the following questions:
Which are the requirements of Boost regarding the C++ language version? C++03? C++11? How can I now which version of Boost requires which version of the C++ language?
Does it depends on the specific library (most of the times, the .hpp file included).
Do I have to check manually (as a last resort) with all the libraries I may need and all the versions of Boost, from the latest and then moving backwards in case I need a less strict dependency?
Which are the dependencies with the C++ Standard Library?
Context:
I am evaluating the use of Boost on an embedded platform (MCU with limited and no virtual memory, no underlying OS).
I have GCC 4.8.1 with C++11 support.
We do not have a complete C++ Standard Library for this platform.
I was hoping to use Boost as a complement and substitute of the C++ Standard Library, hence my research on the topics asked above.
I appreciate the high quality of the Boost project documentation, however, I could not find any reference to the above topics in the official documentation. Maybe I have missed something.
P.S.: A gente introduction to the historically complex topic of C++ language versions, Standard Library and Boost libraries,
http://news.dice.com/2013/03/15/comparing-the-c-standard-and-boost-2/
http://beta.boost.org/development/tests/master/developer/summary.html
This lists some of the platforms boost is tested against.
Every release, boost mentions which platforms it has been tested against.
It is expected to work on more platforms than those listed, but there are no guarantees.
The support and evolution of a boost library in terms of supporting new c++ features is not tightly related to the other libraries. Since boost has been living mainly in a mono standard world (c++03), it was implied that it works in c++03. But as boost people tend to do stuff in a smart way, for the libraries who now support c++11 features, they either use some feature emulation system to keep it working on c++03 or they test for your configuration and if you can't use some advanced stuff then they just disable it.
So basically there is no language standard requirements, it works on all c++03/C++11/C++14 with different features sets.
For other requirements (namely parts of the STL) it directly depends on the libraries you want. The best way is to test. You might find a way to launch their unit test on your plateforme to see how much is working.
You might also want to check Boost Config which is the library that all others use to check for features.
I want to know, or get a clue how to search through a directory in C++ with its own standard libraries or to see if it is possible at all.
Currently I have found several solution to searching directory, but they all use some external libraries such as this SO question:
recursive folder scanning in c++
How should we approach this?
There is no filesystem facilities in the C++ standard. There is a technical specification for it which may be included in a future version of C++.
Until then, you will have to use platform specific functions or a library that wraps them. Apparently the new proposal is almost the same as boost's API, so I recommend using boost even if it's ubiquitousness wasn't good enough reason already.
I want to learn C++ to work on various platform (primarily, Linux and Windows). I have come across few solutions like the Boost C++ library, Qt toolkit, etc that can be used to write programs which will compile on both the platforms.
I want to know from the community, what type of library would you refer to use and if any of you had experience with this type of multi-platform programming before.
Use Qt and the BOOST C++ Libraries. They are both free and very high quality. Also, at least for me personally, I found Qt to be much more straightforward, easy to learn, and simpler than wxWidgets.
It depends on what you're going to do. If you need to write a strictly command-line utility to process text, Qt or wxWidgets might be inappropriate. What exactly is your application field?
Scientific computing is my field of expertise. in which these are great multi-platform APIs:
Parallel Programming
MPI
OpenMP
Numerical Algorithms
BLAS (via Boost's C++ wrappers for BLAS)
LAPACK
LINPACK
PETSc
High-performance file I/O
HDF
NetCDF
Visualization
Visualization Toolkit
If you're doing viz work, a GUI can be great. Try one of the following multi-platform APIs:
Qt
wxWidgets
GTK
The plugin framework for the parallel viz apps:
Paraview
VisIt
You didn't specify any partuclar type of library, but if you just want a general recommendation I have to say wxWidgets is an excellent cross platform GUI library.
It has some great features like rendering the GUI in the native look and feel of the operating system it's running on, and is not particularly hard to learn. It offers a single API for GUI writing across Win/Mac/Linux, plus others like WinCE.
I highly recommend it for cross platform GUI work.
Check it out at http://www.wxwidgets.org/
I highly recommend Qt if you are doing any sort of GUI work; it's even quite useful if you aren't, since it has well-thought out networking/database/container/etc APIs also. It's a very well designed API and very easy to use.
The core C++ standard and the STL are pretty much cross platform already. Its usually only the GUI and hardware access stuff that requires libraries.
I have used GTK+ as a GUI toolkit and it's pretty good too, although you need to install glib and some other stuff on windows.
RtAudio is nice for cross-platform audio I/O.
The low level networking/sockets stuff is largely the same between windows and linux, you could write a very lightweight layer yourself to handle any differences. I don't have any experience with higher-level networking libraries.
I also like the SFML (simple fast media library) for cross-platform 2d graphics type stuff. It's very nice indeed.
I would suggest, however, that if you are just learning c++ then you're probably better off not looking at Boost (or indeed any of these toolkits) until you've got your head around the basics - by writing a couple of basic console applications, for example.
If you want to learn c++ only so you can do multi-platform dev, be aware that there are many other languages and associated toolkits that may be more suitable, depending on the app you're writing.
Without knowing the type of app you're planning on developing, its hard to say whether C++ (or C or Python or whatever) is the best idea. Personally, I generally turn to Python + PyGTK for crossplatform GUI apps and C# for windows-only apps. You can always plug C/C++ in to replace any components that are running too slowly.
Like other posters have mentioned, I would recommend Qt and Boost for cross-platform development. I had tried gtkmm which is a thin C++ wrapper around GTK+, but was not satisfied with it partly because it's not a native C++ library and documentation is poor compared to Qt. Besides that, Qt comes with very nice development environment including a easy-to-write make alternative qmake and a gui designer.
I for are going to do some cross platform development in C++ an you don't want to maintain different build systems (Makefiles, Visual Studio Projects, etc) there are several tools out there that can help you.
The one I personally use is CMake. It supports Linux and Unix Flavours, Windows and Mac/OS. Actually several open source projects, like KDE, use it. But there are others options like for instance Scons.
Standard C++ programs will compile and be portable, i.e. work across a large range of platforms. To be sure that you are keeping code clean, your best bet is to get a few different compiler and check your code with all of them, while enforcing full standard conformance (with options like -std= for g++, for example) and writing warning-free code (with options such as -W -Wall -Werror for g++, which emits errors instead of warnings). The exact choice of compilers is up to you, but if you're mostly learning, I advice using:
g++ (free, open source)
the Intel compiler (free for noncommercial use on Linux)
maybe MSVC++
Also, if you really have to use compiler- or target-specific code in your projects, be sure to abstract it so it's all gathered in one place, and hidden from the rest of your code.
Now, if you want to use more than the STL, then you need to choose your libraries by considering the range of compilers and platforms they're tested against (and, if the documentaiton doesn't state it, it's a bad omen). The detailled choice depends on what exactly you want to do, but Boost (as a robust, wide-ranging library for many common issues) and Qt (a recent version; for GUI programming) are good choices. For numerical, scientific programming, BLAS/LAPACK (and/or their parallel versions, BLACS and Scalapack) are very widely used, directly or through wrapper C++ classes as can be found in Boost (for BLAS); a good FFT library is also often needed (FFTW is good if its GPL licence is not a burden for you).
I've heard a lot of good comments about Boost in the past and thought I would give it a try. So I downloaded all the required packages from the package manager in Ubuntu 9.04. Now I'm having trouble finding out how to actually use the darn libraries.
Does anyone know of a good tutorial on Boost that goes all the way from Hello World to Advanced Topics, and also covers how to compile programs using g++ on ubuntu?
Agreed; the boost website has good tutorials for the most part, broken down by sub-library.
As for compiling, a good 80% of the library implementation is defined in the header files, making compiling trivial. for example, if you wanted to use shared_ptr's, you'd just add
#include <boost/shared_ptr.hpp>
and compile as you normally would. No need to add library paths to your g++ command, or specify -llibboost. As long as the boost directory is in your include path, you're all set.
From the boost documentation:
The only libraries that need to be compiled and linked are the following:The only Boost libraries that must be built separately are:
Boost.Filesystem
Boost.IOStreams
Boost.ProgramOptions
Boost.Python (see the Boost.Python build documentation before building and installing it)
Boost.Regex
Boost.Serialization
Boost.Signals
Boost.Thread
Boost.Wave
A few libraries have optional separately-compiled binaries:
Boost.DateTime has a binary component that is only needed if you're using its to_string/from_string or serialization features, or if you're targeting Visual C++ 6.x or Borland.
Boost.Graph also has a binary component that is only needed if you intend to parse GraphViz files.
Boost.Test can be used in “header-only” or “separately compiled” mode, although separate compilation is recommended for serious use.
So, if you're using one of the listed libraries, use the Getting Started guide to, well, get you started on compiling and linking to Boost.
The Boost website has some good tutorials, they are just kind of hidden.
The library documentation is a mixed bag. Some is good, but some is more of a reference than a guide. The best guide to (some of) the Boost libraries is the book Beyond the C++ Standard Library. At the very least, the introduction gives one paragraph descriptions of many of the libraries. From there, you can decide which library is most important for your current needs, and, if it's in the book, read the chapter on it, or read the documentation on the website.
If you read German, there's a good online guide. Google translate does a good enough job that a non-speaker like me can understand it.
Also, unless you have lots of experience with C++, I'd start with the simpler libraries (e.g. smart_ptr, tuple, conversion, tokenizer, regex, date_time, test), before trying the more complicated ones (bind, variant, any), or the really advanced ones (concepts, MPL, Fusion).
Using Easypeasy 1.1 (for netbooks) which is based upon Ubuntu I was able to use Synaptic Package Manager to install, I believe, libboost-dev. Then simply by adding:
#include "boost/foreach.hpp"
I was able to replace the existing lines in an existing application (which has an Ask class which has nothing to do with boost):
for (std::vector<Ask*>::iterator ii=ui.begin(); ii!=ui.end(); ++ii)
std::cout << (*ii)->prompt() << (*ii)->answer() << std::endl;
with:
BOOST_FOREACH (Ask* ii, ui)
std::cout << ii->prompt() << ii->answer() << std::endl;
As I understand it this is a header only feature. I have not used anything requiring link time changes yet.
I was just looking at that german boost guide, and found there was an english one as well (same book). It looks pretty good, have just read the introductory pages which are quite useful
The best tutorial I've read so far are those two books:
Introduction to the Boost C++ Libraries; Volume I - Foundations
Introduction to the Boost C++ Libraries; Volume II - Advanced Libraries
The libraries come with documentation and many of them have tutorials as part of the documentation. Just start reading.
Boost is not a programming language nor an application framework - because it's just a collection of libraries, there is no such thing as a Boost 'Hello World' program. Most libraries in Boost can be used more or less independently, and they vary in size from one function to massive libraries that could stand alone.
The best way to get to know Boost is simply to try and work it in as you write new code. Use smart_ptr whenever you can; use the MPL next time you want to do compile-time work. There's a lot of variety in Boost, but you should probably start looking at the Utility section; those are the lightest-weight and most commonly-used libraries.
Boost is meant to be the standard non-standard C++ library that every C++ user can use. Is it reasonable to assume it's available for an open source C++ project, or is it a large dependency too far?
Basically your question boils down to “is it reasonable to have [free library xyz] as a dependency for a C++ open source project.”
Now consider the following quote from Stroustrup and the answer is really a no-brainer:
Without a good library, most interesting tasks are hard to do in
C++; but given a good library, almost any task can be made easy
Assuming that this is correct (and in my experience, it is) then writing a reasonably-sized C++ project without dependencies is downright unreasonable.
Developing this argument further, the one C++ dependency (apart from system libraries) that can reasonably be expected on a (developer's) client system is the Boost libraries.
I know that they aren't but it's not an unreasonable presumption for a software to make.
If a software can't even rely on Boost, it can't rely on any library.
Take a look at http://www.boost.org/doc/tools.html. Specifically the bcp utility would come in handy if you would like to embed your boost-dependencies into your project. An excerpt from the web site:
"The bcp utility is a tool for extracting subsets of Boost, it's useful for Boost authors who want to distribute their library separately from Boost, and for Boost users who want to distribute a subset of Boost with their application.bcp can also report on which parts of Boost your code is dependent on, and what licences are used by those dependencies."
Of course this could have some drawbacks - but at least you should be aware of the possibility to do so.
I used to be extremely wary of introducing dependencies to systems, but now I find that dependencies are not a big deal. Modern operating systems come with package managers that can often automatically resolve dependencies or, at least,make it very easy for administrators to install what is needed. For instance, Boost is available under Gentoo-Postage as dev-libs/boost and under FreeBSD ports as devel/boost.
Modern open source software builds a lot on other systems. In a recent study, by tracking the dependencies of the FreeBSD packages, we established that the 12,357 ports packages in our FreeBSD 4.11 system, had in total 21,135 library dependencies; i.e., they required a library, other than the 52 libraries that are part of the base system, in order to compile. The library dependencies comprised 688 different libraries, while the number of different external libraries used by a single project varied between 1 and 38, with a mode value of 2. Furthermore, 5,117 projects used at least one external library and 405 projects used 10 or more.
In the end the answer to your question will come from a cost versus benefit analysis. Is the benefit of re-using a mature, widely used, reviewed, and tested library like Boost and larger than the low and falling cost of a dependency? For any non-trivial use of Boost's facilities the answer is that you should go ahead and use Boost.
It depends. If you're using a header file only defined class template in Boost - then yes go ahead and use it because it doesn't suck in any Boost shared library, as all the code is generated at compile time with no external dependencies. Versioning problems are a pain for any shared c++ library, and Boost is not immune from this, so if you can avoid the problem altogether it's a good thing.
The benefits of using boost when writing C++ code that they significantly outweigh the extra complexity of distributing the open source code.
I work on Programmer's Notepad and the code takes a dependency on boost for test, smart pointers, and python integration. There have been a couple of complaints due to the requirement, but most will just get on with it if they want to work on the code. Taking the boost dependency was a decision I have never regretted.
To make the complexity slightly less for others, I include versioned pre-built libraries for boost python so that all they need to do is provide boost in their include directories.
KDE also depends on Boost.
However it mostly depends on your goals, and even more so on your target audience, rather than the scope of your project. for example TinyJSON (very small project), is almost 100% Boost, but thats fine because the API it provides is Boost-like and targeted at Boost programmers that need JSON bindings. However many other JSON libraries don't use Boost because they target other audiences.
On the other hand I can't use Boost at work, and I know lots of other developers (in their day jobs) are in the same boat. So I guess you could say if your Target is OpenSource, and a group that uses Boost, go ahead. If you target enterprise you might want to think it over and copy-paste just the necessary parts from Boost(and commit to their support) for your project to work.
Edit: The reason we can't use it at work is because our software has
to be portable to about 7 different
platforms and across 4 compilers. So
we can't use boost because it hasn't
been proven to be compatible with
all our targets, so the reason is a
technical one. (We're fine with the
OpenSource and Boost License part,
as we use Boost for other things at
times)
I would say yes. Both Mandriva (Red Hat based) and Ubuntu (Debian based) have packages for the Boost libriaries.
I think the extensive functionality that Boost provides and, as you say, it is the standard non-standard C++ library justifies it as a dependency.
Unfortunately yes, for ubuntu they're readily available but for RHEL 4&5 I've almost always ended up making them from tarballs. They're great libraries, just really big... like using a rail spike when sometimes all you really need is a thumbtack.
It all depends on the way you're going to use Boost. As Diomidis said, if you're going to use some non-trivial facilities from Boost, just go ahead. Using libraries is not a crime.
Of course, there are many people who prefer not to use Boost, because introducing new dependencies has always some cons and extra worries, but in an open source project... in my opinion it's even alright to use them if you just want to learn them or improve your skills on them.