fgetpos ¶POSIX specification:
https://pubs.opengroup.org/onlinepubs/9799919799/functions/fgetpos.html
Gnulib module: —
Portability problems fixed by Gnulib:
off_t is a 32-bit type, this function may not
work correctly on files 2 GiB and larger. See Large File Support.
Portability problems not fixed by Gnulib:
fflush, ftell, ftello, fgetpos behave incorrectly
on input streams that are opened in O_TEXT mode and whose contents
contains Unix line terminators (LF), on some platforms: mingw, MSVC 14.