seekable input stream to the byte after the last one actually read:
glibc 2.13, FreeBSD.
@item
+This function crashes if the stream's file descriptor has already been
+closed on some platforms:
+MSVC 9.
+@item
On Windows platforms (excluding Cygwin), @code{socket} and @code{accept}
followed by @code{fdopen} do not return streams that can be closed by
@code{fclose}.