..
  Copyright 1988-2021 Free Software Foundation, Inc.
  This is part of the GCC manual.
  For copying conditions, see the GPL license file

.. _runtime:

Runtime:  Influencing runtime behavior with environment variables
-----------------------------------------------------------------

.. index:: environment variable

The behavior of the :command:`gfortran` can be influenced by
environment variables.

Malformed environment variables are silently ignored.

.. toctree::
  :maxdepth: 2

  runtime-influencing-runtime-behavior-with-environment-variables/tmpdir-directory-for-scratch-files
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranstdinunit-unit-number-for-standard-input
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranstdoutunit-unit-number-for-standard-output
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranstderrunit-unit-number-for-standard-error
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranunbufferedall-do-not-buffer-i-o-on-all-units
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranunbufferedpreconnected-do-not-buffer-i-o-on-preconnected-units
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranshowlocus-show-location-for-runtime-errors
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranoptionalplus-print-leading-+-where-permitted
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranlistseparator-separator-for-list-output
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranconvertunit-set-endianness-for-unformatted-i-o
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranerrorbacktrace-show-backtrace-on-run-time-errors
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranformattedbuffersize-set-buffer-size-for-formatted-i-o
  runtime-influencing-runtime-behavior-with-environment-variables/gfortranunformattedbuffersize-set-buffer-size-for-unformatted-i-o