Re: [boost] [filesystem] How to remove specific files from a directory?

Subject: Re: [boost] [filesystem] How to remove specific files from a directory?
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2016-09-07 09:46:52

On 09/07/16 16:06, Andrzej Krzemienski wrote:
> Hi,
> I wonder what is boost::filesystem recommendation for solving the following
> problem.
>
> I want to remove all files from a given directory that satisfy a certain
> predicate, e.g., only these whose names start with letter "s".
>
> It is my understanding that the calling filesystem::remove may invalidate
> the iterator, and therefore the following solution is incorrect:
>
> fsys::directory_iterator it{path}, itEnd{};
> for ( ; it != itEnd ; ++it )
> {
>   if (predicate(*it))
>     fsys::remove(it->path());
> }
>
> But, is the following guaranteed to work?:
>
> fsys::directory_iterator it{path}, itEnd{};
> for ( ; it != itEnd ; )
> {
>   if (predicate(*it))
>     fsys::remove((it++)->path());
>   else
>     ++it;
> }

 From the documentation, it seems the behavior should be similar to 
readdir, in which case it would seem that both pieces of code above are 
valid. Although I would prefer the second one as it is more in line with 
common practices in C++.

> If not, does there exist a dedicated solution for solving this problem that
> would not require of me N traversals through the directory?

If you still want a different solution, you could collect the matching 
file names on the directory traversal and delete the files in the second 
loop.