Mercurial > hg > sv-dependency-builds

annotate src/fftw-3.3.5/doc/html/Wisdom-Generic-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 2cd0e3b3e1fd
children
rev   line source
Chris@42 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
Chris@42 2 <html>
Chris@42 3 <!-- This manual is for FFTW
Chris@42 4 (version 3.3.5, 30 July 2016).
Chris@42 5
Chris@42 6 Copyright (C) 2003 Matteo Frigo.
Chris@42 7
Chris@42 8 Copyright (C) 2003 Massachusetts Institute of Technology.
Chris@42 9
Chris@42 10 Permission is granted to make and distribute verbatim copies of this
Chris@42 11 manual provided the copyright notice and this permission notice are
Chris@42 12 preserved on all copies.
Chris@42 13
Chris@42 14 Permission is granted to copy and distribute modified versions of this
Chris@42 15 manual under the conditions for verbatim copying, provided that the
Chris@42 16 entire resulting derived work is distributed under the terms of a
Chris@42 17 permission notice identical to this one.
Chris@42 18
Chris@42 19 Permission is granted to copy and distribute translations of this manual
Chris@42 20 into another language, under the above conditions for modified versions,
Chris@42 21 except that this permission notice may be stated in a translation
Chris@42 22 approved by the Free Software Foundation. -->
Chris@42 23 <!-- Created by GNU Texinfo 5.2, http://www.gnu.org/software/texinfo/ -->
Chris@42 24 <head>
Chris@42 25 <title>FFTW 3.3.5: Wisdom Generic Export/Import from Fortran</title>
Chris@42 26
Chris@42 27 <meta name="description" content="FFTW 3.3.5: Wisdom Generic Export/Import from Fortran">
Chris@42 28 <meta name="keywords" content="FFTW 3.3.5: Wisdom Generic Export/Import from Fortran">
Chris@42 29 <meta name="resource-type" content="document">
Chris@42 30 <meta name="distribution" content="global">
Chris@42 31 <meta name="Generator" content="makeinfo">
Chris@42 32 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Chris@42 33 <link href="index.html#Top" rel="start" title="Top">
Chris@42 34 <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index">
Chris@42 35 <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
Chris@42 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@42 37 <link href="Defining-an-FFTW-module.html#Defining-an-FFTW-module" rel="next" title="Defining an FFTW module">
Chris@42 38 <link href="Wisdom-String-Export_002fImport-from-Fortran.html#Wisdom-String-Export_002fImport-from-Fortran" rel="prev" title="Wisdom String Export/Import from Fortran">
Chris@42 39 <style type="text/css">
Chris@42 40 <!--
Chris@42 41 a.summary-letter {text-decoration: none}
Chris@42 42 blockquote.smallquotation {font-size: smaller}
Chris@42 43 div.display {margin-left: 3.2em}
Chris@42 44 div.example {margin-left: 3.2em}
Chris@42 45 div.indentedblock {margin-left: 3.2em}
Chris@42 46 div.lisp {margin-left: 3.2em}
Chris@42 47 div.smalldisplay {margin-left: 3.2em}
Chris@42 48 div.smallexample {margin-left: 3.2em}
Chris@42 49 div.smallindentedblock {margin-left: 3.2em; font-size: smaller}
Chris@42 50 div.smalllisp {margin-left: 3.2em}
Chris@42 51 kbd {font-style:oblique}
Chris@42 52 pre.display {font-family: inherit}
Chris@42 53 pre.format {font-family: inherit}
Chris@42 54 pre.menu-comment {font-family: serif}
Chris@42 55 pre.menu-preformatted {font-family: serif}
Chris@42 56 pre.smalldisplay {font-family: inherit; font-size: smaller}
Chris@42 57 pre.smallexample {font-size: smaller}
Chris@42 58 pre.smallformat {font-family: inherit; font-size: smaller}
Chris@42 59 pre.smalllisp {font-size: smaller}
Chris@42 60 span.nocodebreak {white-space:nowrap}
Chris@42 61 span.nolinebreak {white-space:nowrap}
Chris@42 62 span.roman {font-family:serif; font-weight:normal}
Chris@42 63 span.sansserif {font-family:sans-serif; font-weight:normal}
Chris@42 64 ul.no-bullet {list-style: none}
Chris@42 65 -->
Chris@42 66 </style>
Chris@42 67
Chris@42 68
Chris@42 69 </head>
Chris@42 70
Chris@42 71 <body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000">
Chris@42 72 <a name="Wisdom-Generic-Export_002fImport-from-Fortran"></a>
Chris@42 73 <div class="header">
Chris@42 74 <p>
Chris@42 75 Previous: <a href="Wisdom-String-Export_002fImport-from-Fortran.html#Wisdom-String-Export_002fImport-from-Fortran" accesskey="p" rel="prev">Wisdom String 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@42 76 </div>
Chris@42 77 <hr>
Chris@42 78 <a name="Wisdom-Generic-Export_002fImport-from-Fortran-1"></a>
Chris@42 79 <h4 class="subsection">7.6.3 Wisdom Generic Export/Import from Fortran</h4>
Chris@42 80
Chris@42 81 <p>The most generic wisdom export/import functions allow you to provide
Chris@42 82 an arbitrary callback function to read/write one character at a time
Chris@42 83 in any way you want. However, your callback function must be written
Chris@42 84 in a special way, using the <code>bind(C)</code> attribute to be passed to a
Chris@42 85 C interface.
Chris@42 86 </p>
Chris@42 87 <a name="index-fftw_005fexport_005fwisdom-1"></a>
Chris@42 88 <p>In particular, to call the generic wisdom export function
Chris@42 89 <code>fftw_export_wisdom</code>, you would write a callback subroutine of the form:
Chris@42 90 </p>
Chris@42 91 <div class="example">
Chris@42 92 <pre class="example"> subroutine my_write_char(c, p) bind(C)
Chris@42 93 use, intrinsic :: iso_c_binding
Chris@42 94 character(C_CHAR), value :: c
Chris@42 95 type(C_PTR), value :: p
Chris@42 96 <em>...write c...</em>
Chris@42 97 end subroutine my_write_char
Chris@42 98 </pre></div>
Chris@42 99
Chris@42 100 <p>Given such a subroutine (along with the corresponding interface definition), you could then export wisdom using:
Chris@42 101 </p>
Chris@42 102 <a name="index-c_005ffunloc"></a>
Chris@42 103 <div class="example">
Chris@42 104 <pre class="example"> call fftw_export_wisdom(c_funloc(my_write_char), p)
Chris@42 105 </pre></div>
Chris@42 106
Chris@42 107 <a name="index-c_005floc"></a>
Chris@42 108 <a name="index-c_005ff_005fpointer-4"></a>
Chris@42 109 <p>The standard <code>c_funloc</code> intrinsic converts a Fortran
Chris@42 110 <code>bind(C)</code> subroutine into a C function pointer. The parameter
Chris@42 111 <code>p</code> is a <code>type(C_PTR)</code> to any arbitrary data that you want
Chris@42 112 to pass to <code>my_write_char</code> (or <code>C_NULL_PTR</code> if none). (Note
Chris@42 113 that you can get a C pointer to Fortran data using the intrinsic
Chris@42 114 <code>c_loc</code>, and convert it back to a Fortran pointer in
Chris@42 115 <code>my_write_char</code> using <code>c_f_pointer</code>.)
Chris@42 116 </p>
Chris@42 117 <p>Similarly, to use the generic <code>fftw_import_wisdom</code>, you would
Chris@42 118 define a callback function of the form:
Chris@42 119 </p>
Chris@42 120 <a name="index-fftw_005fimport_005fwisdom-1"></a>
Chris@42 121 <div class="example">
Chris@42 122 <pre class="example"> integer(C_INT) function my_read_char(p) bind(C)
Chris@42 123 use, intrinsic :: iso_c_binding
Chris@42 124 type(C_PTR), value :: p
Chris@42 125 character :: c
Chris@42 126 <em>...read a character c...</em>
Chris@42 127 my_read_char = ichar(c, C_INT)
Chris@42 128 end function my_read_char
Chris@42 129
Chris@42 130 ....
Chris@42 131
Chris@42 132 integer(C_INT) :: ret
Chris@42 133 ret = fftw_import_wisdom(c_funloc(my_read_char), p)
Chris@42 134 if (ret .eq. 0) stop 'error importing wisdom'
Chris@42 135 </pre></div>
Chris@42 136
Chris@42 137 <p>Your function can return <code>-1</code> if the end of the input is reached.
Chris@42 138 Again, <code>p</code> is an arbitrary <code>type(C_PTR</code> that is passed
Chris@42 139 through to your function. <code>fftw_import_wisdom</code> returns <code>0</code>
Chris@42 140 if an error occurred and nonzero otherwise.
Chris@42 141 </p>
Chris@42 142 <hr>
Chris@42 143 <div class="header">
Chris@42 144 <p>
Chris@42 145 Previous: <a href="Wisdom-String-Export_002fImport-from-Fortran.html#Wisdom-String-Export_002fImport-from-Fortran" accesskey="p" rel="prev">Wisdom String 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@42 146 </div>
Chris@42 147
Chris@42 148
Chris@42 149
Chris@42 150 </body>
Chris@42 151 </html>