<html lang="en"> <head> <title>Introduction to Intrinsics - 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="up" href="Intrinsic-Procedures.html#Intrinsic-Procedures" title="Intrinsic Procedures"> <link rel="next" href="ABORT.html#ABORT" title="ABORT"> <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="Introduction-to-Intrinsics"></a> <p> Next: <a rel="next" accesskey="n" href="ABORT.html#ABORT">ABORT</a>, Up: <a rel="up" accesskey="u" href="Intrinsic-Procedures.html#Intrinsic-Procedures">Intrinsic Procedures</a> <hr> </div> <h3 class="section">8.1 Introduction to intrinsic procedures</h3> <p>The intrinsic procedures provided by GNU Fortran include all of the intrinsic procedures required by the Fortran 95 standard, a set of intrinsic procedures for backwards compatibility with G77, and a selection of intrinsic procedures from the Fortran 2003 and Fortran 2008 standards. Any conflict between a description here and a description in either the Fortran 95 standard, the Fortran 2003 standard or the Fortran 2008 standard is unintentional, and the standard(s) should be considered authoritative. <p>The enumeration of the <code>KIND</code> type parameter is processor defined in the Fortran 95 standard. GNU Fortran defines the default integer type and default real type by <code>INTEGER(KIND=4)</code> and <code>REAL(KIND=4)</code>, respectively. The standard mandates that both data types shall have another kind, which have more precision. On typical target architectures supported by <samp><span class="command">gfortran</span></samp>, this kind type parameter is <code>KIND=8</code>. Hence, <code>REAL(KIND=8)</code> and <code>DOUBLE PRECISION</code> are equivalent. In the description of generic intrinsic procedures, the kind type parameter will be specified by <code>KIND=*</code>, and in the description of specific names for an intrinsic procedure the kind type parameter will be explicitly given (e.g., <code>REAL(KIND=4)</code> or <code>REAL(KIND=8)</code>). Finally, for brevity the optional <code>KIND=</code> syntax will be omitted. <p>Many of the intrinsic procedures take one or more optional arguments. This document follows the convention used in the Fortran 95 standard, and denotes such arguments by square brackets. <p>GNU Fortran offers the <samp><span class="option">-std=f95</span></samp> and <samp><span class="option">-std=gnu</span></samp> options, which can be used to restrict the set of intrinsic procedures to a given standard. By default, <samp><span class="command">gfortran</span></samp> sets the <samp><span class="option">-std=gnu</span></samp> option, and so all intrinsic procedures described here are accepted. There is one caveat. For a select group of intrinsic procedures, <samp><span class="command">g77</span></samp> implemented both a function and a subroutine. Both classes have been implemented in <samp><span class="command">gfortran</span></samp> for backwards compatibility with <samp><span class="command">g77</span></samp>. It is noted here that these functions and subroutines cannot be intermixed in a given subprogram. In the descriptions that follow, the applicable standard for each intrinsic procedure is noted. </body></html>