| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| <html> |
| <!-- Copyright (C) 1999-2014 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. --> |
| <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ --> |
| <head> |
| <title>The GNU Fortran Compiler: STRUCTURE and RECORD</title> |
| |
| <meta name="description" content="The GNU Fortran Compiler: STRUCTURE and RECORD"> |
| <meta name="keywords" content="The GNU Fortran Compiler: STRUCTURE and RECORD"> |
| <meta name="resource-type" content="document"> |
| <meta name="distribution" content="global"> |
| <meta name="Generator" content="makeinfo"> |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> |
| <link href="index.html#Top" rel="start" title="Top"> |
| <link href="Option-Index.html#Option-Index" rel="index" title="Option Index"> |
| <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> |
| <link href="Extensions-not-implemented-in-GNU-Fortran.html#Extensions-not-implemented-in-GNU-Fortran" rel="up" title="Extensions not implemented in GNU Fortran"> |
| <link href="ENCODE-and-DECODE-statements.html#ENCODE-and-DECODE-statements" rel="next" title="ENCODE and DECODE statements"> |
| <link href="Extensions-not-implemented-in-GNU-Fortran.html#Extensions-not-implemented-in-GNU-Fortran" rel="prev" title="Extensions not implemented in GNU Fortran"> |
| <style type="text/css"> |
| <!-- |
| a.summary-letter {text-decoration: none} |
| blockquote.smallquotation {font-size: smaller} |
| div.display {margin-left: 3.2em} |
| div.example {margin-left: 3.2em} |
| div.indentedblock {margin-left: 3.2em} |
| div.lisp {margin-left: 3.2em} |
| div.smalldisplay {margin-left: 3.2em} |
| div.smallexample {margin-left: 3.2em} |
| div.smallindentedblock {margin-left: 3.2em; font-size: smaller} |
| div.smalllisp {margin-left: 3.2em} |
| kbd {font-style:oblique} |
| pre.display {font-family: inherit} |
| pre.format {font-family: inherit} |
| pre.menu-comment {font-family: serif} |
| pre.menu-preformatted {font-family: serif} |
| pre.smalldisplay {font-family: inherit; font-size: smaller} |
| pre.smallexample {font-size: smaller} |
| pre.smallformat {font-family: inherit; font-size: smaller} |
| pre.smalllisp {font-size: smaller} |
| span.nocodebreak {white-space:nowrap} |
| span.nolinebreak {white-space:nowrap} |
| span.roman {font-family:serif; font-weight:normal} |
| span.sansserif {font-family:sans-serif; font-weight:normal} |
| ul.no-bullet {list-style: none} |
| --> |
| </style> |
| |
| |
| </head> |
| |
| <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> |
| <a name="STRUCTURE-and-RECORD"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="ENCODE-and-DECODE-statements.html#ENCODE-and-DECODE-statements" accesskey="n" rel="next">ENCODE and DECODE statements</a>, Up: <a href="Extensions-not-implemented-in-GNU-Fortran.html#Extensions-not-implemented-in-GNU-Fortran" accesskey="u" rel="up">Extensions not implemented in GNU Fortran</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> |
| </div> |
| <hr> |
| <a name="STRUCTURE-and-RECORD-1"></a> |
| <h4 class="subsection">6.2.1 <code>STRUCTURE</code> and <code>RECORD</code></h4> |
| <a name="index-STRUCTURE"></a> |
| <a name="index-RECORD"></a> |
| |
| <p>Record structures are a pre-Fortran-90 vendor extension to create |
| user-defined aggregate data types. GNU Fortran does not support |
| record structures, only Fortran 90’s “derived types”, which have |
| a different syntax. |
| </p> |
| <p>In many cases, record structures can easily be converted to derived types. |
| To convert, replace <code>STRUCTURE /</code><var>structure-name</var><code>/</code> |
| by <code>TYPE</code> <var>type-name</var>. Additionally, replace |
| <code>RECORD /</code><var>structure-name</var><code>/</code> by |
| <code>TYPE(</code><var>type-name</var><code>)</code>. Finally, in the component access, |
| replace the period (<code>.</code>) by the percent sign (<code>%</code>). |
| </p> |
| <p>Here is an example of code using the non portable record structure syntax: |
| </p> |
| <div class="example"> |
| <pre class="example">! Declaring a structure named ``item'' and containing three fields: |
| ! an integer ID, an description string and a floating-point price. |
| STRUCTURE /item/ |
| INTEGER id |
| CHARACTER(LEN=200) description |
| REAL price |
| END STRUCTURE |
| |
| ! Define two variables, an single record of type ``item'' |
| ! named ``pear'', and an array of items named ``store_catalog'' |
| RECORD /item/ pear, store_catalog(100) |
| |
| ! We can directly access the fields of both variables |
| pear.id = 92316 |
| pear.description = "juicy D'Anjou pear" |
| pear.price = 0.15 |
| store_catalog(7).id = 7831 |
| store_catalog(7).description = "milk bottle" |
| store_catalog(7).price = 1.2 |
| |
| ! We can also manipulate the whole structure |
| store_catalog(12) = pear |
| print *, store_catalog(12) |
| </pre></div> |
| |
| <p>This code can easily be rewritten in the Fortran 90 syntax as following: |
| </p> |
| <div class="example"> |
| <pre class="example">! ``STRUCTURE /name/ ... END STRUCTURE'' becomes |
| ! ``TYPE name ... END TYPE'' |
| TYPE item |
| INTEGER id |
| CHARACTER(LEN=200) description |
| REAL price |
| END TYPE |
| |
| ! ``RECORD /name/ variable'' becomes ``TYPE(name) variable'' |
| TYPE(item) pear, store_catalog(100) |
| |
| ! Instead of using a dot (.) to access fields of a record, the |
| ! standard syntax uses a percent sign (%) |
| pear%id = 92316 |
| pear%description = "juicy D'Anjou pear" |
| pear%price = 0.15 |
| store_catalog(7)%id = 7831 |
| store_catalog(7)%description = "milk bottle" |
| store_catalog(7)%price = 1.2 |
| |
| ! Assignments of a whole variable do not change |
| store_catalog(12) = pear |
| print *, store_catalog(12) |
| </pre></div> |
| |
| |
| |
| |
| <hr> |
| <div class="header"> |
| <p> |
| Next: <a href="ENCODE-and-DECODE-statements.html#ENCODE-and-DECODE-statements" accesskey="n" rel="next">ENCODE and DECODE statements</a>, Up: <a href="Extensions-not-implemented-in-GNU-Fortran.html#Extensions-not-implemented-in-GNU-Fortran" accesskey="u" rel="up">Extensions not implemented in GNU Fortran</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> |
| </div> |
| |
| |
| |
| </body> |
| </html> |
