Comments on: C++ Boost Filesystem Library(Part III): Example Programs

By: tabrez

tabrez — Sun, 06 Jan 2008 18:10:20 +0000

I have written a shorter procedure to get started with Boost libraries under Visual Studio .NET IDEs using Boost Consulting installer:
http://beans.seartipy.com/2007/08/20/installing-c-boost-on-microsoft-windows-for-visual-studio-net-20032005/

It does register the fact that Internet connection is required ;)

Getting STLPort and C++ Boost to work together had been a great pain in the neck for me when I had last tried it(both on windows and gnu/linux). Will give it a try again(it needs to be built separately from Boost by the way, using Microsoft compiler).

By: paul bates

paul bates — Sat, 05 Jan 2008 17:45:00 +0000

I used the Boost Consulting installer. It would have helped to know that it needs internet access to run (this is not mentioned in the Getting Started withBoost documentation). However when I ran it on a machine with internet access it ran very smoothly and seemed to almost give me the libraries I need. Unfortunately I am using STLport and the linker searches for libraries containing ‘-p-’. These libraries were not downloaded and I can see no mention in the getting started documentation on how to build them. They were not built by bjam -sTOOLS=msvc stage

By: Simon Blackhart

Simon Blackhart — Fri, 28 Dec 2007 03:22:17 +0000

Hey P.,

I had the same question and I found the answer here:

http://blog.codedread.com/archives/2007/07/12/getting-to-know-c-next-filesystem/

Hope it helps, it’ll sure help me out, gotta love the net!

By: Petrus

Petrus — Thu, 13 Dec 2007 00:53:48 +0000

Dear Tabrez:

I am a total and I mean, total, newbie to Boost. It took me a major effort to get it running. I have…finally. Anyway, I need to traverse a large number of directories and their sub-directories. I am looking (Win platform) for files ending in a given extension (…as it happens, .php). Is there a quick way to match with a wild card or something similar so that I can get ALL files that are *.php?

Even a pointer to the correct documentation would be a big help.

Best,

By: tabrez

tabrez — Mon, 03 Dec 2007 14:51:02 +0000

If only the single-exit vs multiple-exit point style debates were so straight-forward. They both make sense in different contexts but in many cases, yes, it is just a matter of style. Couple of examples where single-exit style is undesirable:

SESE forces an additional nested block, and hence an additional level of indentation too, where preconditions/arguments need to be checked before executing the actual implementation.
SESE sometimes makes creation of temporary objects more inefficient than SEME would - e.g. returning string literal(only constructor called) vs returning a string object(constructor and assignment operator called).
SESE doesn't make sense when there are multiple implicit exit points anyway - e.g. code with exceptions. You can say that recommending SESE as a rule or a standard for languages that support exceptions is obsolete - or at least over-emphasising it is.

I mostly prefer SEME, but the reason with regard to code in this specific post, though, was only to save a couple of lines.

By: VS

VS — Sun, 02 Dec 2007 21:10:29 +0000

Overall I have found your post helpful regarding the use of the boost:filesystem classes. Just a comment/question on style: Why most everyone that has presented the directory iterators capability always uses a function with four return statements (I found it c-ish, confusing, and annoying). You can easily modify the code so as to leave only one exit point. For instance:


bool find_file(const bfs::path & dir_path, const std::string & file_name, bfs::path & pfound)
{
    bool successFlag(false);
    if( exists(dir_path) && is_directory(dir_path) ) 
    {
        bfs::directory_iterator iter(dir_path), end_iter;
        for(; iter!= end_iter; ++iter)
        {
            if( bfs::is_directory(*iter) )
            {
                if( find_file(*iter, file_name, pfound) )
                     successFlag = true;
                     break;
            }
            else if( iter->leaf() == file_name )
            {
                 pfound = *iter;
                 successFlag = true;
                 break;
            }
        }
        return successFlag;
    }
}

I think this would work as well, and turns easier to follow. Trivial, but not so trivial when you write a couple thousand lines of code...