windowswinapitemporary-fileshunspell

Windows directory that will never contain non-ASCII characters for temp file?

Using MinGW 7.3.0 on Windows, Hunspell can't load the dictionary files from locations that have non-ASCII characters because of Windows limitations. I've tried everything[1] and I'm now resorting to copying the file to a path without ASCII characters before giving it to Hunspell. What is a good location to copy it to?

[1]

  1. Windows requires wchar_t support for std::iostream.open() to work right, which MinGW does not implement
  2. std::filesystem can solve this, but only available in GCC 8
  3. Hunspell insists on loading files on its own, it is not possible to pass the read files as strings to it
Solution

  • The "natural" fit would be the use the user's choosen temporary directory (or subdirectory thereof) (see %temp% or GetTempPath()). However, that defaults to something that contains the user name (which can contain "non-ASCII" characters; e.g. c:\users\Ø¥Ć¼\AppData\LocalLow\Temp) or something arbitrary (regarding character set) all together.

    So you're most likely best off to choose some directory that

    a) does not contain off-limits characters from the get go. For example, a directory underneath C:\ProgramData that you choose yourself (e.g. the application name) that you know does not contain non-ASCII characters.

    b) let the user decide where to put these files and make sure it is not permissible to enter a path that contains only allowed characters.

    c) Pass the "short path name" to Hunspell, which should not contain non-ASCII characters for compatibility with FAT file system traits. For example, the short path name for c:\temp\Ø¥Ć¼ is c:\temp\571D~1.

    You can see the short names for directories using cmd.exe /c dir /x:

    C:\temp>dir /x
...    
19.07.2019  15:30    <DIR>                       .
19.07.2019  15:30    <DIR>                       ..
19.07.2019  15:30    <DIR>          571D~1       Ø¥Ć¼

    How you can invoke the GetShortPathName Win32 API from MinGW I don't know, but I would assume that it is possible.

    Also make sure to review the MSDN page for the above function for traitoffs, e.g. short names are not supported everywhere (e.g. SMB + see comments below).