c++ - Using _wopen() under windows shell namespace extension -

i'm developing kind of windows shell namespace extension(ne). extension provides custom context menu element file , folders. among other things need create new file under ne. i'm trying create file like:

auto flags = o_wronly | o_creat | o_trunc | o_binary | o_cloexec; auto fd = _wopen(l"c:\\test.txt", flags , 0666); 

i tryed use "\\?\" prefix:

auto flags = o_wronly | o_creat | o_trunc | o_binary | o_cloexec; auto fd = _wopen(l"\\\\?\\c:\\test.txt", flags , 0666); 

anyway returned file descriptor negative , errno eacces - 'permission denied' missing?

users cannot create files in c:\ (without elevation).

the shell extension runs credentials of current user, cannot create files there.