GFORTRAN_UNBUFFERED_PRECONNECTED—Do not buffer I/O on preconnected units

The environment variable named GFORTRAN_UNBUFFERED_PRECONNECTED controls whether I/O on a preconnected unit (i.e. STDOUT or STDERR) is unbuffered. If the first letter is y, Y or 1, I/O is unbuffered. This will slow down small sequential reads and writes. If the first letter is n, N or 0, I/O is buffered. This is the default.