fflush (GNU Gnulib)

Gnulib module: fflush

Portability problems fixed by Gnulib:

fflush followed by fseek or fseeko, applied to an input stream, should have the effect of positioning the underlying file descriptor. It doesn’t do this on some platforms: glibc 2.34, FreeBSD 14.0, and others.
fflush on an input stream changes the position of the stream to the end of the previous buffer, on some platforms: mingw, MSVC 14.
fflush on an input stream right after ungetc does not discard the ungetc buffer, on some platforms: macOS 14, FreeBSD 6.0, NetBSD 10.0, OpenBSD 6.7, Cygwin 1.5.25-10.

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.
On Windows platforms (excluding Cygwin), this function does not set errno upon failure.
This function crashes if the stream’s file descriptor has already been closed, if MSVC_INVALID_PARAMETER_HANDLING is HAIRY_LIBRARY_HANDLING or SANE_LIBRARY_HANDLING, on some platforms: MSVC 14.
fflush on an input stream right after ungetc does not discard the ungetc buffer, on some platforms: AIX 5.1, HP-UX 11, Solaris 11 2010-11, mingw, MSVC 14.