125 lines
5.4 KiB
HTML
125 lines
5.4 KiB
HTML
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
|
|
<html>
|
||
|
|
<!-- This manual is for FFTW
|
||
|
|
(version 3.3.10, 10 December 2020).
|
||
|
|
|
||
|
|
Copyright (C) 2003 Matteo Frigo.
|
||
|
|
|
||
|
|
Copyright (C) 2003 Massachusetts Institute of Technology.
|
||
|
|
|
||
|
|
Permission is granted to make and distribute verbatim copies of this
|
||
|
|
manual provided the copyright notice and this permission notice are
|
||
|
|
preserved on all copies.
|
||
|
|
|
||
|
|
Permission is granted to copy and distribute modified versions of this
|
||
|
|
manual under the conditions for verbatim copying, provided that the
|
||
|
|
entire resulting derived work is distributed under the terms of a
|
||
|
|
permission notice identical to this one.
|
||
|
|
|
||
|
|
Permission is granted to copy and distribute translations of this manual
|
||
|
|
into another language, under the above conditions for modified versions,
|
||
|
|
except that this permission notice may be stated in a translation
|
||
|
|
approved by the Free Software Foundation. -->
|
||
|
|
<!-- Created by GNU Texinfo 6.7, http://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<title>Wisdom String Export/Import from Fortran (FFTW 3.3.10)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Wisdom String Export/Import from Fortran (FFTW 3.3.10)">
|
||
|
|
<meta name="keywords" content="Wisdom String Export/Import from Fortran (FFTW 3.3.10)">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content="makeinfo">
|
||
|
|
<link href="index.html" rel="start" title="Top">
|
||
|
|
<link href="Concept-Index.html" rel="index" title="Concept Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Accessing-the-wisdom-API-from-Fortran.html" rel="up" title="Accessing the wisdom API from Fortran">
|
||
|
|
<link href="Wisdom-Generic-Export_002fImport-from-Fortran.html" rel="next" title="Wisdom Generic Export/Import from Fortran">
|
||
|
|
<link href="Wisdom-File-Export_002fImport-from-Fortran.html" rel="prev" title="Wisdom File Export/Import from Fortran">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.summary-letter {text-decoration: none}
|
||
|
|
blockquote.indentedblock {margin-right: 0em}
|
||
|
|
div.display {margin-left: 3.2em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
div.lisp {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}
|
||
|
|
span.nolinebreak {white-space: nowrap}
|
||
|
|
span.roman {font-family: initial; font-weight: normal}
|
||
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
||
|
|
ul.no-bullet {list-style: none}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en">
|
||
|
|
<span id="Wisdom-String-Export_002fImport-from-Fortran"></span><div class="header">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Wisdom-Generic-Export_002fImport-from-Fortran.html" accesskey="n" rel="next">Wisdom Generic Export/Import from Fortran</a>, Previous: <a href="Wisdom-File-Export_002fImport-from-Fortran.html" accesskey="p" rel="prev">Wisdom File Export/Import from Fortran</a>, Up: <a href="Accessing-the-wisdom-API-from-Fortran.html" accesskey="u" rel="up">Accessing the wisdom API from Fortran</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<span id="Wisdom-String-Export_002fImport-from-Fortran-1"></span><h4 class="subsection">7.6.2 Wisdom String Export/Import from Fortran</h4>
|
||
|
|
|
||
|
|
<span id="index-fftw_005fexport_005fwisdom_005fto_005fstring-1"></span>
|
||
|
|
<p>Dealing with FFTW’s C string export/import is a bit more painful. In
|
||
|
|
particular, the <code>fftw_export_wisdom_to_string</code> function requires
|
||
|
|
you to deal with a dynamically allocated C string. To get its length,
|
||
|
|
you must define an interface to the C <code>strlen</code> function, and to
|
||
|
|
deallocate it you must define an interface to C <code>free</code>:
|
||
|
|
</p>
|
||
|
|
<div class="example">
|
||
|
|
<pre class="example"> use, intrinsic :: iso_c_binding
|
||
|
|
interface
|
||
|
|
integer(C_INT) function strlen(s) bind(C, name='strlen')
|
||
|
|
import
|
||
|
|
type(C_PTR), value :: s
|
||
|
|
end function strlen
|
||
|
|
subroutine free(p) bind(C, name='free')
|
||
|
|
import
|
||
|
|
type(C_PTR), value :: p
|
||
|
|
end subroutine free
|
||
|
|
end interface
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>Given these definitions, you can then export wisdom to a Fortran
|
||
|
|
character array:
|
||
|
|
</p>
|
||
|
|
<div class="example">
|
||
|
|
<pre class="example"> character(C_CHAR), pointer :: s(:)
|
||
|
|
integer(C_SIZE_T) :: slen
|
||
|
|
type(C_PTR) :: p
|
||
|
|
p = fftw_export_wisdom_to_string()
|
||
|
|
if (.not. c_associated(p)) stop 'error exporting wisdom'
|
||
|
|
slen = strlen(p)
|
||
|
|
call c_f_pointer(p, s, [slen+1])
|
||
|
|
...
|
||
|
|
call free(p)
|
||
|
|
</pre></div>
|
||
|
|
<span id="index-c_005fassociated"></span>
|
||
|
|
<span id="index-c_005ff_005fpointer-3"></span>
|
||
|
|
|
||
|
|
<p>Note that <code>slen</code> is the length of the C string, but the length of
|
||
|
|
the array is <code>slen+1</code> because it includes the terminating null
|
||
|
|
character. (You can omit the ‘<samp>+1</samp>’ if you don’t want Fortran to
|
||
|
|
know about the null character.) The standard <code>c_associated</code> function
|
||
|
|
checks whether <code>p</code> is a null pointer, which is returned by
|
||
|
|
<code>fftw_export_wisdom_to_string</code> if there was an error.
|
||
|
|
</p>
|
||
|
|
<span id="index-fftw_005fimport_005fwisdom_005ffrom_005fstring-1"></span>
|
||
|
|
<p>To import wisdom from a string, use
|
||
|
|
<code>fftw_import_wisdom_from_string</code> as usual; note that the argument
|
||
|
|
of this function must be a <code>character(C_CHAR)</code> that is terminated
|
||
|
|
by the <code>C_NULL_CHAR</code> character, like the <code>s</code> array above.
|
||
|
|
</p>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|