<html lang="en">
<head>
<title>Runtime - The GNU Fortran Compiler</title>
<meta http-equiv="Content-Type" content="text/html">
<meta name="description" content="The GNU Fortran Compiler">
<meta name="generator" content="makeinfo 4.13">
<link title="Top" rel="start" href="index.html#Top">
<link rel="prev" href="Invoking-GNU-Fortran.html#Invoking-GNU-Fortran" title="Invoking GNU Fortran">
<link rel="next" href="Fortran-2003-and-2008-status.html#Fortran-2003-and-2008-status" title="Fortran 2003 and 2008 status">
<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
<!--
Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``Funding Free Software'', the Front-Cover
Texts being (a) (see below), and with the Back-Cover Texts being (b)
(see below). A copy of the license is included in the section entitled
``GNU Free Documentation License''.
(a) The FSF's Front-Cover Text is:
A GNU Manual
(b) The FSF's Back-Cover Text is:
You have freedom to copy and modify this GNU Manual, like GNU
software. Copies published by the Free Software Foundation raise
funds for GNU development.-->
<meta http-equiv="Content-Style-Type" content="text/css">
<style type="text/css"><!--
pre.display { font-family:inherit }
pre.format { font-family:inherit }
pre.smalldisplay { font-family:inherit; font-size:smaller }
pre.smallformat { font-family:inherit; font-size:smaller }
pre.smallexample { font-size:smaller }
pre.smalllisp { font-size:smaller }
span.sc { font-variant:small-caps }
span.roman { font-family:serif; font-weight:normal; }
span.sansserif { font-family:sans-serif; font-weight:normal; }
--></style>
</head>
<body>
<div class="node">
<a name="Runtime"></a>
<p>
Next: <a rel="next" accesskey="n" href="Fortran-2003-and-2008-status.html#Fortran-2003-and-2008-status">Fortran 2003 and 2008 status</a>,
Previous: <a rel="previous" accesskey="p" href="Invoking-GNU-Fortran.html#Invoking-GNU-Fortran">Invoking GNU Fortran</a>,
Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a>
<hr>
</div>
<h2 class="chapter">3 Runtime: Influencing runtime behavior with environment variables</h2>
<p><a name="index-environment-variable-273"></a>
The behavior of the <samp><span class="command">gfortran</span></samp> can be influenced by
environment variables.
<p>Malformed environment variables are silently ignored.
<ul class="menu">
<li><a accesskey="1" href="GFORTRAN_005fSTDIN_005fUNIT.html#GFORTRAN_005fSTDIN_005fUNIT">GFORTRAN_STDIN_UNIT</a>: Unit number for standard input
<li><a accesskey="2" href="GFORTRAN_005fSTDOUT_005fUNIT.html#GFORTRAN_005fSTDOUT_005fUNIT">GFORTRAN_STDOUT_UNIT</a>: Unit number for standard output
<li><a accesskey="3" href="GFORTRAN_005fSTDERR_005fUNIT.html#GFORTRAN_005fSTDERR_005fUNIT">GFORTRAN_STDERR_UNIT</a>: Unit number for standard error
<li><a accesskey="4" href="GFORTRAN_005fUSE_005fSTDERR.html#GFORTRAN_005fUSE_005fSTDERR">GFORTRAN_USE_STDERR</a>: Send library output to standard error
<li><a accesskey="5" href="GFORTRAN_005fTMPDIR.html#GFORTRAN_005fTMPDIR">GFORTRAN_TMPDIR</a>: Directory for scratch files
<li><a accesskey="6" href="GFORTRAN_005fUNBUFFERED_005fALL.html#GFORTRAN_005fUNBUFFERED_005fALL">GFORTRAN_UNBUFFERED_ALL</a>: Don't buffer I/O for all units.
<li><a accesskey="7" href="GFORTRAN_005fUNBUFFERED_005fPRECONNECTED.html#GFORTRAN_005fUNBUFFERED_005fPRECONNECTED">GFORTRAN_UNBUFFERED_PRECONNECTED</a>: Don't buffer I/O for preconnected units.
<li><a accesskey="8" href="GFORTRAN_005fSHOW_005fLOCUS.html#GFORTRAN_005fSHOW_005fLOCUS">GFORTRAN_SHOW_LOCUS</a>: Show location for runtime errors
<li><a accesskey="9" href="GFORTRAN_005fOPTIONAL_005fPLUS.html#GFORTRAN_005fOPTIONAL_005fPLUS">GFORTRAN_OPTIONAL_PLUS</a>: Print leading + where permitted
<li><a href="GFORTRAN_005fDEFAULT_005fRECL.html#GFORTRAN_005fDEFAULT_005fRECL">GFORTRAN_DEFAULT_RECL</a>: Default record length for new files
<li><a href="GFORTRAN_005fLIST_005fSEPARATOR.html#GFORTRAN_005fLIST_005fSEPARATOR">GFORTRAN_LIST_SEPARATOR</a>: Separator for list output
<li><a href="GFORTRAN_005fCONVERT_005fUNIT.html#GFORTRAN_005fCONVERT_005fUNIT">GFORTRAN_CONVERT_UNIT</a>: Set endianness for unformatted I/O
<li><a href="GFORTRAN_005fERROR_005fDUMPCORE.html#GFORTRAN_005fERROR_005fDUMPCORE">GFORTRAN_ERROR_DUMPCORE</a>: Dump core on run-time errors
<li><a href="GFORTRAN_005fERROR_005fBACKTRACE.html#GFORTRAN_005fERROR_005fBACKTRACE">GFORTRAN_ERROR_BACKTRACE</a>: Show backtrace on run-time errors
</ul>
</body></html>
