Re: [Boost-users] filesystem::path crash on Windows when dealing with umlauts ( üëï )

Subject: Re: [Boost-users] filesystem::path crash on Windows when dealing with umlauts ( üëï )
From: Rainer Deyke (rainerd_at_[hidden])
Date: 2019-05-08 12:58:56

On 08.05.19 14:35, Gonzalo Garramuño via Boost-users wrote:
> I am getting a crash on Windows when passing a path that contains 
> umlauts (like sampëüö ) to the path constructor.
> 
> I tried boost 1.69 and boost 1.60.
> 
> Here's the code I am using:
> 
>  Â  namespace fs = boost::filesystem;
> 
>  Â  const char* tmp = setlocale(LC_ALL, N_(""));
> 
>  Â  // Create and install global locale
> std::locale::global(boost::locale::generator().generate( N_("") ));
> 
>  Â  // Make boost.filesystem use it
>  Â  fs::path::imbue(std::locale());
> 
>  Â  if ( !tmp )Â  tmp = setlocale( LC_ALL, NULL );
> 
>  Â  std::string program = argv[0];
>  Â  fs::path file = fs::path( program );Â Â  // CRASH

This has nothing to do with boost::filesystem, but...

Don't use argv[0] on Windows, and generally don't use argv for path 
arguments on Windows.  Any Windows program that uses argv[0] for any 
purpose other than diagnostic output is incorrect.

The reason is, of course, that Windows transforms unicode paths into the 
local codepage in order to generate argv, which is a lossy operation 
that can cause non-ASCII characters to be replaced with other characters 
or to be dropped entirely.  You might think that this doesn't matter to 
you because you run in a locale that can represent all of the characters 
in your path.  However, I can guarantee that this will not hold true for 
all of your users.

Use GetCommandLineW to get the actual Unicode command line, 
CommandLineToArgvW to convert it to UTF-16, then convert from that to 
UTF-8 or some other sane representation.  Or just pass the wchar string 
directly to boost::filesystem.

argv[0] is broken on Windows.  Do not use it.

-- 
Rainer Deyke - rainerd_at_[hidden]