mbed::fdopen() is provided in mbed_retarget.cpp which will attach a stream to the
given FileHandle. Removing mbed_set_unbuffered_stream() from stream class as it
is defined in mbed_retarget.cpp. Stream class should not decide whether it wants
to detach buffers from c library or not. mbed::fdopen() will do that based upon
isatty() call. So if a FileHandle is not a tty, i.e., is not a device type, c library
buffering will not be turned off. For device type FileHandles, c library buffering
is turned off.
failing on file allocation / opening during Stream creation.
The consequence was application continues running, but any printf
to the Serial object whose Stream was not properly created
would not show any error (and characters would not show either)
Let's add a check to properly inform user of the error.
Martin Kojtal
Senthil Ramakrishnan
Hasnain Virk
Kevin Bracey
Laurent MEUNIER
Christopher Haster