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

7 Sep 2016


      On 7 September 2016 at 15:46, Andrey Semashev  wrote:
...
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.
Indeed, boost::filesystem and std::filesystem (ISO/IEC TS 18822:2015) as well
as POSIX readdir behave in the same way.
But, for all of them, behaviour is unspecified in case content of
directory that is
being traversed changes.

Best regards,
-- 
Mateusz Loskot, http://mateusz.loskot.net