529 lines
21 KiB
HTML
529 lines
21 KiB
HTML
<!doctype html>
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<html lang="en">
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<head>
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<meta charset="utf-8">
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<title>foreign-c a portable foreign function interface for R7RS
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Schemes - 0.10.0</title>
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<style>
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table { width: 250%; }
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nav { float: left; width: 20%;}
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main { float: right; width: 80%; }
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pre { background-color: lightgrey; }
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</style>
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</head>
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<body>
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<h1 id="foreign-c">foreign-c</h1>
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<p>foreign-c is a C foreign function interface (FFI) library for
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R7RS Schemes. It is portable in the sense that it supports
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multiple implementations, as opposed to being portable by
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conforming to some specification.</p>
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<p><a href="https://sr.ht/~retropikzel/foreign-c/trackers">Issue
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tracker</a></p>
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<p><a href="https://sr.ht/~retropikzel/foreign-c/lists">Maling
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lists</a></p>
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<ul>
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<li><a href="#installation">Installation</a></li>
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<li><a href="#documentation">Documentation</a>
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<ul>
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<li><a href="#types">Types</a></li>
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<li><a href="#primitives-1">Primitives 1</a></li>
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<li><a href="#primitives-2">Primitives 2</a></li>
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<li><a href="#c-bytevector">c-bytevector</a>
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<ul>
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<li><a href="#creation-and-deletion">Creationg and
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deletion</a></li>
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<li><a href="#accessors">Accessors</a></li>
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</ul></li>
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<li><a href="#environment-variables">Environment
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variables</a></li>
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</ul></li>
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</ul>
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<h2 id="implementation-support-tables">Implementation support
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tables</h2>
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<h3 id="primitives-1-table">Primitives 1 table</h3>
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<table>
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<colgroup>
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<col style="width: 13%" />
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<col style="width: 10%" />
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<col style="width: 16%" />
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<col style="width: 15%" />
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<col style="width: 16%" />
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<col style="width: 11%" />
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<col style="width: 16%" />
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</colgroup>
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<thead>
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<tr class="header">
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<th></th>
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<th style="text-align: center;">c-size-of</th>
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<th style="text-align: center;">c-bytevector-u8-set!</th>
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<th style="text-align: center;">c-bytevector-u8-ref</th>
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<th style="text-align: center;">define-c-library</th>
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<th style="text-align: center;">c-bytevector?</th>
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<th style="text-align: center;">define-c-procedure</th>
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</tr>
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</thead>
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<tbody>
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<tr class="odd">
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<td><strong>Chibi</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="even">
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<td><strong>Chicken</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td><strong>Gauche</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="even">
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<td><strong>Guile</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td><strong>Kawa</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="even">
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<td><strong>Mosh</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td><strong>Racket</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="even">
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<td><strong>Saggittarius</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td><strong>Stklos</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="even">
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<td><strong>Ypsilon</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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</tr>
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</tbody>
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</table>
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<h3 id="primitives-2-table">Primitives 2 table</h3>
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<table>
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<thead>
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<tr class="header">
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<th></th>
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<th style="text-align: center;">define-c-callback</th>
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</tr>
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</thead>
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<tbody>
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<tr class="odd">
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<td>Chibi</td>
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<td style="text-align: center;"></td>
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</tr>
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<tr class="even">
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<td><strong>Chicken</strong></td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td>Gauche</td>
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<td style="text-align: center;"></td>
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</tr>
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<tr class="even">
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<td><strong>Guile</strong></td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td>Kawa</td>
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<td style="text-align: center;"></td>
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</tr>
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<tr class="even">
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<td><strong>Mosh</strong></td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td><strong>Racket</strong></td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="even">
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<td><strong>Saggittarius</strong></td>
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<td style="text-align: center;">X</td>
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</tr>
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<tr class="odd">
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<td>Stklos</td>
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<td style="text-align: center;"></td>
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</tr>
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<tr class="even">
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<td><strong>Ypsilon</strong></td>
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<td style="text-align: center;">X</td>
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</tr>
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</tbody>
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</table>
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<h3 id="test-files-pass">Test files pass</h3>
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<table>
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<thead>
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<tr class="header">
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<th></th>
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<th style="text-align: center;">primitives.scm</th>
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<th style="text-align: center;">addressof.scm</th>
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<th style="text-align: right;">callback.scm</th>
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</tr>
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</thead>
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<tbody>
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<tr class="odd">
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<td>Chibi</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;"></td>
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</tr>
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<tr class="even">
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<td><strong>Chicken</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;">X</td>
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</tr>
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<tr class="odd">
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<td>Gauche</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;"></td>
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</tr>
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<tr class="even">
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<td><strong>Guile</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;">X</td>
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</tr>
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<tr class="odd">
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<td>Kawa</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;"></td>
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</tr>
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<tr class="even">
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<td>Mosh</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;"></td>
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</tr>
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<tr class="odd">
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<td>Racket</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;"></td>
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<td style="text-align: right;"></td>
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</tr>
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<tr class="even">
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<td><strong>Saggittarius</strong></td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;">X</td>
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</tr>
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<tr class="odd">
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<td>Stklos</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;"></td>
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</tr>
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<tr class="even">
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<td>Ypsilon</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: center;">X</td>
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<td style="text-align: right;"></td>
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</tr>
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</tbody>
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</table>
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<h3 id="installation">Installation</h3>
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<p>Either download the latest release from <a
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href="https://git.sr.ht/~retropikzel/foreign-c/refs">https://git.sr.ht/~retropikzel/foreign-c/refs</a>
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or git clone , preferably with a tag, and copy the
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<em>foreign</em> directory to your library directory.</p>
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<p>Example assuming libraries in directory <em>snow</em>:</p>
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<pre><code>git clone https://git.sr.ht/~retropikzel/foreign-c --branch LATEST_VERSION
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mkdir -p snow
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cp -r foreign-c/foreign snow/
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make -C snow/foreign/c SCHEME_IMPLEMENTATION_NAME</code></pre>
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<p>With most implementations the make command does not compile
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anything. When that is the case it will say “Nothing to build on
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SCHEME_IMPLEMENTATION_NAME.”</p>
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<h2 id="documentation">Documentation</h2>
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<h3 id="types">Types</h3>
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<p>Types are given as symbols, for example ’int8 or
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’pointer.</p>
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<ul>
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<li>int8</li>
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<li>uint8</li>
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<li>int16</li>
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<li>uint16</li>
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<li>int32</li>
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<li>uint32</li>
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<li>int64</li>
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<li>uint64</li>
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<li>char</li>
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<li>unsigned-char</li>
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<li>short</li>
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<li>unsigned-short</li>
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<li>int</li>
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<li>unsigned-int</li>
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<li>long</li>
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<li>unsigned-long</li>
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<li>float</li>
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<li>double</li>
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<li>pointer
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<ul>
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<li>c-bytevector on Scheme side</li>
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</ul></li>
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<li>callback
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<ul>
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<li>Callback function</li>
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</ul></li>
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<li>void
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<ul>
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<li>Can not be argument type, only return type</li>
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</ul></li>
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</ul>
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<h3 id="primitives-1">Primitives 1</h3>
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<p>(<strong>c-type-size</strong> <em>type</em>)</p>
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<p>Returns the size of given C type.</p>
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<p>(<strong>define-c-library</strong> <em>scheme-name</em>
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<em>headers</em> <em>object-name</em> <em>options</em>)</p>
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<p>Takes a scheme-name to bind the library to, list of C headers
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as strings, shared-object name and options.</p>
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<p>The C header strings should not contain “<” or “>”,
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they are added automatically.</p>
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<p>The name of the shared object should not contain suffix like
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.so or .dll. Nor should it contain any prefix like “lib”.</p>
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<p>Options:</p>
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<ul>
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<li>additional-versions
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<ul>
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<li>Search for additional versions of shared object, given
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shared object “c” and additional versions “6” “7” on linux the
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files “libc”, “libc.6”, “libc.7” are searched for.</li>
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<li>Can be either numbers or strings</li>
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</ul></li>
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<li>additional-paths
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<ul>
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<li>Give additional paths to search shared objects from</li>
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</ul></li>
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</ul>
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<p>Example:</p>
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<pre><code>(cond-expand
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(windows (define-c-library libc-stdlib
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'("stdlib.h")
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"ucrtbase"
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'((additional-versions ("0" "6"))
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(additiona-paths (".")))))
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(else (define-c-library libc-stdlib
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(list "stdlib.h")
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"c"
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'((additional-versions ("0" "6"))
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(additiona-paths ("."))))))</code></pre>
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<h4 id="notes">Notes</h4>
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<ul>
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<li>Do not cond-expand inside the arguments, that might lead to
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problems on some implementations.</li>
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<li>Do not store options in variables, that might lead to
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problems on some implementations.</li>
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<li>Pass the headers using quote
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<ul>
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<li>As ’(…) and not (list…)</li>
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</ul></li>
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<li>Pass the options using quote
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<ul>
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<li>As ’(…) and not (list…)</li>
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</ul></li>
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</ul>
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<p>(<strong>define-c-procedure</strong> <em>scheme-name</em>
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<em>shared-object</em> <em>c-name</em> <em>return-type</em>
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<em>argument-type</em>)</p>
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<p>Takes a scheme-name to bind the C procedure to, shared-object
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where the function is looked from, c-name of the function as
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symbol, return-type and argument-types.</p>
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<p>Defines a new foreign function to be used from Scheme
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code.</p>
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<p>Example:</p>
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<pre><code>(cond-expand
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(windows (define-c-library libc-stdlib '("stdlib.h") "ucrtbase" '()))
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(else (define-c-library libc-stdlib '("stdlib.h") "c" '("6"))))
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(define-c-procedure c-puts libc-stdlib 'puts 'int '(pointer))
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(c-puts "Message brought to you by foreign-c!")</code></pre>
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<h4 id="notes-1">Notes</h4>
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<ul>
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<li>Pass the return-types using quote
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<ul>
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<li>As ’(…) and not (list…)</li>
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</ul></li>
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</ul>
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<p>(<strong>c-bytevector?</strong> <em>obj</em>)</p>
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<p>Returns <strong>#t</strong> if <em>obj</em> is c-bytevector,
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otherwise returns <strong>#f</strong>.</p>
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<p>(<strong>c-bytevector-u8-set!</strong> <em>c-bytevector</em>
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<em>k</em> <em>byte</em>)</p>
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<p>If K is not a valid index of c-bytevector the behaviour is
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undefined.</p>
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<p>Stores the byte in element k of c-bytevector.</p>
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<p>(<strong>c-bytevector-u8-ref</strong> <em>c-bytevector</em>
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<em>k</em>)</p>
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<p>If K is not a valid index of c-bytevector the behaviour is
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undefined.</p>
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<p>Returns the byte at index k of c-bytevector.</p>
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<p>(<strong>c-bytevector-pointer-set!</strong>
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<em>c-bytevector</em> <em>k</em> <em>pointer</em>)</p>
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<p>If K is not a valid index of c-bytevector the behaviour is
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undefined.</p>
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<p>Stores the pointer(which is also c-bytevector) in element k
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of c-bytevector.</p>
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<p>(<strong>c-bytevector-pointer-ref</strong>
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<em>c-bytevector</em> <em>k</em> <em>pointer</em>)</p>
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<p>If K is not a valid index of c-bytevector the behaviour is
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undefined.</p>
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<p>Returns the pointer(which is also c-bytevector) at index k of
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c-bytevector.</p>
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<h3 id="primitives-2">Primitives 2</h3>
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<p>(<strong>define-c-callback</strong> <em>scheme-name</em>
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<em>return-type</em> <em>argument-types</em>
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<em>procedure</em>)</p>
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<p>Takes scheme-name to bind the Scheme procedure to,
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return-type, argument-types and procedure as in place
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lambda.</p>
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<p>Defines a new Sceme function to be used as callback to C
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code.</p>
|
||
<p>Example:</p>
|
||
<pre><code>; Load the shared library
|
||
(cond-expand
|
||
(windows (define-c-library libc-stdlib '("stdlib.h") "ucrtbase" '()))
|
||
(else (define-c-library '("stdlib.h") "c" '("" "6"))))
|
||
|
||
; Define C function that takes a callback
|
||
(define-c-procedure qsort libc-stdlib 'qsort 'void '(pointer int int callback))
|
||
|
||
; Define our callback
|
||
(pffi-define-callback compare
|
||
'int
|
||
'(pointer pointer)
|
||
(lambda (pointer-a pointer-b)
|
||
(let ((a (pffi-pointer-get pointer-a 'int 0))
|
||
(b (pffi-pointer-get pointer-b 'int 0)))
|
||
(cond ((> a b) 1)
|
||
((= a b) 0)
|
||
((< a b) -1)))))
|
||
|
||
; Create new array of ints to be sorted
|
||
(define array (make-c-bytevector (* (c-size-of 'int) 3)))
|
||
(pffi-pointer-set! array 'int (* (c-size-of 'int) 0) 3)
|
||
(pffi-pointer-set! array 'int (* (c-size-of 'int) 1) 2)
|
||
(pffi-pointer-set! array 'int (* (c-size-of 'int) 2) 1)
|
||
|
||
(display array)
|
||
(newline)
|
||
;> (3 2 1)
|
||
|
||
; Sort the array
|
||
(qsort array 3 (c-size-of 'int) compare)
|
||
|
||
(display array)
|
||
(newline)
|
||
;> (1 2 3)</code></pre>
|
||
<h3 id="c-bytevector">c-bytevector</h3>
|
||
<h4 id="creation-and-deletion">Creation and deletion</h4>
|
||
<p>(<strong>make-c-null</strong>)</p>
|
||
<p>Returns a null C pointer.</p>
|
||
<p>(<strong>c-null?</strong> <em>obj</em>)</p>
|
||
<p>Returns <strong>#t</strong> if <em>obj</em> is a null C
|
||
pointer, otherwise returns <strong>#f</strong>.</p>
|
||
<p>(<strong>c-free</strong> <em>c-bytevector</em>)</p>
|
||
<p>Frees <em>c-bytevector</em> from memory.</p>
|
||
<p>(<strong>make-c-bytevector</strong> <em>k</em>)
|
||
(<strong>make-c-bytevector</strong> <em>k</em>
|
||
<em>fill</em>)</p>
|
||
<p>Returns a newly allocated c-bytevector of <em>k</em>
|
||
bytes.</p>
|
||
<p>If the <em>fill</em> argument is missing, the initial
|
||
contents of the returned c-bytevector are unspecified.</p>
|
||
<p>If the <em>fill</em> argument is present, it’s value must
|
||
confine to C uint8_t values , it specifies the initial value for
|
||
the bytes of the c-bytevector</p>
|
||
<h4 id="accessors">Accessors</h4>
|
||
<p>(<strong>native-endianness</strong>)</p>
|
||
<p>c-bytevector-s8-set! c-bytevector-s8-ref
|
||
c-bytevector-s16-set! c-bytevector-s16-ref
|
||
c-bytevector-s16-native-set! c-bytevector-s16-native-ref
|
||
c-bytevector-u16-set! c-bytevector-u16-ref
|
||
c-bytevector-u16-native-set! c-bytevector-u16-native-ref
|
||
c-bytevector-s32-set! c-bytevector-s32-ref
|
||
c-bytevector-s32-native-set! c-bytevector-s32-native-ref
|
||
c-bytevector-u32-set! c-bytevector-u32-ref
|
||
c-bytevector-u32-native-set! c-bytevector-u32-native-ref
|
||
c-bytevector-s64-set! c-bytevector-s64-ref
|
||
c-bytevector-s64-native-set! c-bytevector-s64-native-ref
|
||
c-bytevector-u64-set! c-bytevector-u64-ref
|
||
c-bytevector-u64-native-set! c-bytevector-u64-native-ref
|
||
c-bytevector-sint-set! c-bytevector-sint-ref
|
||
c-bytevector-uint-set! c-bytevector-uint-ref
|
||
c-bytevector-ieee-single-set!
|
||
c-bytevector-ieee-single-native-set!
|
||
c-bytevector-ieee-single-ref c-bytevector-ieee-single-native-ref
|
||
c-bytevector-ieee-double-set!
|
||
c-bytevector-ieee-double-native-set!
|
||
c-bytevector-ieee-double-ref c-bytevector-ieee-double-native-ref
|
||
bytevector->c-bytevector c-bytevector->bytevector
|
||
call-with-address-of</p>
|
||
<p>string->c-utf8 c-utf8->string</p>
|
||
<h3 id="environment-variables">Environment variables</h3>
|
||
<p>Setting environment variables like this on Windows works for
|
||
this library:</p>
|
||
<pre><code>set "PFFI_LOAD_PATH=C:\Program Files (x86)/foo/bar"</code></pre>
|
||
<h4 id="pffi_load_path">PFFI_LOAD_PATH</h4>
|
||
<p>To add more paths to where pffi looks for libraries set
|
||
PFFI_LOAD_PATH to paths separated by ; on windows, and : on
|
||
other operating systems.</p>
|
||
</body>
|
||
</html>
|