Mercurial > hg > sv-dependency-builds

annotate src/fftw-3.3.8/doc/html/Wisdom-String-Export_002fImport-from-Fortran.html @ 83:ae30d91d2ffe

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Replace these with versions built using an older toolset (so as to avoid ABI compatibilities when linking on Ubuntu 14.04 for packaging purposes)
author Chris Cannam
date Fri, 07 Feb 2020 11:51:13 +0000
parents d0c2a83c1364
children
rev   line source
Chris@82 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
Chris@82 2 <html>
Chris@82 3 <!-- This manual is for FFTW
Chris@82 4 (version 3.3.8, 24 May 2018).
Chris@82 5
Chris@82 6 Copyright (C) 2003 Matteo Frigo.
Chris@82 7
Chris@82 8 Copyright (C) 2003 Massachusetts Institute of Technology.
Chris@82 9
Chris@82 10 Permission is granted to make and distribute verbatim copies of this
Chris@82 11 manual provided the copyright notice and this permission notice are
Chris@82 12 preserved on all copies.
Chris@82 13
Chris@82 14 Permission is granted to copy and distribute modified versions of this
Chris@82 15 manual under the conditions for verbatim copying, provided that the
Chris@82 16 entire resulting derived work is distributed under the terms of a
Chris@82 17 permission notice identical to this one.
Chris@82 18
Chris@82 19 Permission is granted to copy and distribute translations of this manual
Chris@82 20 into another language, under the above conditions for modified versions,
Chris@82 21 except that this permission notice may be stated in a translation
Chris@82 22 approved by the Free Software Foundation. -->
Chris@82 23 <!-- Created by GNU Texinfo 6.3, http://www.gnu.org/software/texinfo/ -->
Chris@82 24 <head>
Chris@82 25 <title>FFTW 3.3.8: Wisdom String Export/Import from Fortran</title>
Chris@82 26
Chris@82 27 <meta name="description" content="FFTW 3.3.8: Wisdom String Export/Import from Fortran">
Chris@82 28 <meta name="keywords" content="FFTW 3.3.8: Wisdom String Export/Import from Fortran">
Chris@82 29 <meta name="resource-type" content="document">
Chris@82 30 <meta name="distribution" content="global">
Chris@82 31 <meta name="Generator" content="makeinfo">
Chris@82 32 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Chris@82 33 <link href="index.html#Top" rel="start" title="Top">
Chris@82 34 <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
Chris@82 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
Chris@82 36 <link href="Accessing-the-wisdom-API-from-Fortran.html#Accessing-the-wisdom-API-from-Fortran" rel="up" title="Accessing the wisdom API from Fortran">
Chris@82 37 <link href="Wisdom-Generic-Export_002fImport-from-Fortran.html#Wisdom-Generic-Export_002fImport-from-Fortran" rel="next" title="Wisdom Generic Export/Import from Fortran">
Chris@82 38 <link href="Wisdom-File-Export_002fImport-from-Fortran.html#Wisdom-File-Export_002fImport-from-Fortran" rel="prev" title="Wisdom File Export/Import from Fortran">
Chris@82 39 <style type="text/css">
Chris@82 40 <!--
Chris@82 41 a.summary-letter {text-decoration: none}
Chris@82 42 blockquote.indentedblock {margin-right: 0em}
Chris@82 43 blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
Chris@82 44 blockquote.smallquotation {font-size: smaller}
Chris@82 45 div.display {margin-left: 3.2em}
Chris@82 46 div.example {margin-left: 3.2em}
Chris@82 47 div.lisp {margin-left: 3.2em}
Chris@82 48 div.smalldisplay {margin-left: 3.2em}
Chris@82 49 div.smallexample {margin-left: 3.2em}
Chris@82 50 div.smalllisp {margin-left: 3.2em}
Chris@82 51 kbd {font-style: oblique}
Chris@82 52 pre.display {font-family: inherit}
Chris@82 53 pre.format {font-family: inherit}
Chris@82 54 pre.menu-comment {font-family: serif}
Chris@82 55 pre.menu-preformatted {font-family: serif}
Chris@82 56 pre.smalldisplay {font-family: inherit; font-size: smaller}
Chris@82 57 pre.smallexample {font-size: smaller}
Chris@82 58 pre.smallformat {font-family: inherit; font-size: smaller}
Chris@82 59 pre.smalllisp {font-size: smaller}
Chris@82 60 span.nolinebreak {white-space: nowrap}
Chris@82 61 span.roman {font-family: initial; font-weight: normal}
Chris@82 62 span.sansserif {font-family: sans-serif; font-weight: normal}
Chris@82 63 ul.no-bullet {list-style: none}
Chris@82 64 -->
Chris@82 65 </style>
Chris@82 66
Chris@82 67
Chris@82 68 </head>
Chris@82 69
Chris@82 70 <body lang="en">
Chris@82 71 <a name="Wisdom-String-Export_002fImport-from-Fortran"></a>
Chris@82 72 <div class="header">
Chris@82 73 <p>
Chris@82 74 Next: <a href="Wisdom-Generic-Export_002fImport-from-Fortran.html#Wisdom-Generic-Export_002fImport-from-Fortran" accesskey="n" rel="next">Wisdom Generic Export/Import from Fortran</a>, Previous: <a href="Wisdom-File-Export_002fImport-from-Fortran.html#Wisdom-File-Export_002fImport-from-Fortran" accesskey="p" rel="prev">Wisdom File Export/Import from Fortran</a>, Up: <a href="Accessing-the-wisdom-API-from-Fortran.html#Accessing-the-wisdom-API-from-Fortran" accesskey="u" rel="up">Accessing the wisdom API from Fortran</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
Chris@82 75 </div>
Chris@82 76 <hr>
Chris@82 77 <a name="Wisdom-String-Export_002fImport-from-Fortran-1"></a>
Chris@82 78 <h4 class="subsection">7.6.2 Wisdom String Export/Import from Fortran</h4>
Chris@82 79
Chris@82 80 <a name="index-fftw_005fexport_005fwisdom_005fto_005fstring-1"></a>
Chris@82 81 <p>Dealing with FFTW&rsquo;s C string export/import is a bit more painful. In
Chris@82 82 particular, the <code>fftw_export_wisdom_to_string</code> function requires
Chris@82 83 you to deal with a dynamically allocated C string. To get its length,
Chris@82 84 you must define an interface to the C <code>strlen</code> function, and to
Chris@82 85 deallocate it you must define an interface to C <code>free</code>:
Chris@82 86 </p>
Chris@82 87 <div class="example">
Chris@82 88 <pre class="example"> use, intrinsic :: iso_c_binding
Chris@82 89 interface
Chris@82 90 integer(C_INT) function strlen(s) bind(C, name='strlen')
Chris@82 91 import
Chris@82 92 type(C_PTR), value :: s
Chris@82 93 end function strlen
Chris@82 94 subroutine free(p) bind(C, name='free')
Chris@82 95 import
Chris@82 96 type(C_PTR), value :: p
Chris@82 97 end subroutine free
Chris@82 98 end interface
Chris@82 99 </pre></div>
Chris@82 100
Chris@82 101 <p>Given these definitions, you can then export wisdom to a Fortran
Chris@82 102 character array:
Chris@82 103 </p>
Chris@82 104 <div class="example">
Chris@82 105 <pre class="example"> character(C_CHAR), pointer :: s(:)
Chris@82 106 integer(C_SIZE_T) :: slen
Chris@82 107 type(C_PTR) :: p
Chris@82 108 p = fftw_export_wisdom_to_string()
Chris@82 109 if (.not. c_associated(p)) stop 'error exporting wisdom'
Chris@82 110 slen = strlen(p)
Chris@82 111 call c_f_pointer(p, s, [slen+1])
Chris@82 112 ...
Chris@82 113 call free(p)
Chris@82 114 </pre></div>
Chris@82 115 <a name="index-c_005fassociated"></a>
Chris@82 116 <a name="index-c_005ff_005fpointer-3"></a>
Chris@82 117
Chris@82 118 <p>Note that <code>slen</code> is the length of the C string, but the length of
Chris@82 119 the array is <code>slen+1</code> because it includes the terminating null
Chris@82 120 character. (You can omit the &lsquo;<samp>+1</samp>&rsquo; if you don&rsquo;t want Fortran to
Chris@82 121 know about the null character.) The standard <code>c_associated</code> function
Chris@82 122 checks whether <code>p</code> is a null pointer, which is returned by
Chris@82 123 <code>fftw_export_wisdom_to_string</code> if there was an error.
Chris@82 124 </p>
Chris@82 125 <a name="index-fftw_005fimport_005fwisdom_005ffrom_005fstring-1"></a>
Chris@82 126 <p>To import wisdom from a string, use
Chris@82 127 <code>fftw_import_wisdom_from_string</code> as usual; note that the argument
Chris@82 128 of this function must be a <code>character(C_CHAR)</code> that is terminated
Chris@82 129 by the <code>C_NULL_CHAR</code> character, like the <code>s</code> array above.
Chris@82 130 </p>
Chris@82 131
Chris@82 132
Chris@82 133
Chris@82 134 </body>
Chris@82 135 </html>