<html lang="en"> <head> <title>Preprocessing directives implementation - Using the GNU Compiler Collection (GCC)</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="Using the GNU Compiler Collection (GCC)"> <meta name="generator" content="makeinfo 4.13"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="C-Implementation.html#C-Implementation" title="C Implementation"> <link rel="prev" href="Statements-implementation.html#Statements-implementation" title="Statements implementation"> <link rel="next" href="Library-functions-implementation.html#Library-functions-implementation" title="Library functions implementation"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- Copyright (C) 1988-2015 Free Software Foundation, Inc. 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Copies published by the Free Software Foundation raise funds for GNU development.--> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family:serif; font-weight:normal; } span.sansserif { font-family:sans-serif; font-weight:normal; } --></style> </head> <body> <div class="node"> <a name="Preprocessing-directives-implementation"></a> <p> Next: <a rel="next" accesskey="n" href="Library-functions-implementation.html#Library-functions-implementation">Library functions implementation</a>, Previous: <a rel="previous" accesskey="p" href="Statements-implementation.html#Statements-implementation">Statements implementation</a>, Up: <a rel="up" accesskey="u" href="C-Implementation.html#C-Implementation">C Implementation</a> <hr> </div> <h3 class="section">4.13 Preprocessing Directives</h3> <p>See <a href="../cpp/Implementation_002ddefined-behavior.html#Implementation_002ddefined-behavior">Implementation-defined behavior</a>, for details of these aspects of implementation-defined behavior. <ul> <li><cite>The locations within </cite><code>#pragma</code><cite> directives where header name preprocessing tokens are recognized (C11 6.4, C11 6.4.7).</cite> <li><cite>How sequences in both forms of header names are mapped to headers or external source file names (C90 6.1.7, C99 and C11 6.4.7).</cite> <li><cite>Whether the value of a character constant in a constant expression that controls conditional inclusion matches the value of the same character constant in the execution character set (C90 6.8.1, C99 and C11 6.10.1).</cite> <li><cite>Whether the value of a single-character character constant in a constant expression that controls conditional inclusion may have a negative value (C90 6.8.1, C99 and C11 6.10.1).</cite> <li><cite>The places that are searched for an included ‘</cite><samp><span class="samp"><></span></samp><cite>’ delimited header, and how the places are specified or the header is identified (C90 6.8.2, C99 and C11 6.10.2).</cite> <li><cite>How the named source file is searched for in an included ‘</cite><samp><span class="samp">""</span></samp><cite>’ delimited header (C90 6.8.2, C99 and C11 6.10.2).</cite> <li><cite>The method by which preprocessing tokens (possibly resulting from macro expansion) in a </cite><code>#include</code><cite> directive are combined into a header name (C90 6.8.2, C99 and C11 6.10.2).</cite> <li><cite>The nesting limit for </cite><code>#include</code><cite> processing (C90 6.8.2, C99 and C11 6.10.2).</cite> <li><cite>Whether the ‘</cite><samp><span class="samp">#</span></samp><cite>’ operator inserts a ‘</cite><samp><span class="samp">\</span></samp><cite>’ character before the ‘</cite><samp><span class="samp">\</span></samp><cite>’ character that begins a universal character name in a character constant or string literal (C99 and C11 6.10.3.2).</cite> <li><cite>The behavior on each recognized non-</cite><code>STDC #pragma</code><cite> directive (C90 6.8.6, C99 and C11 6.10.6).</cite> <p>See <a href="../cpp/Pragmas.html#Pragmas">Pragmas</a>, for details of pragmas accepted by GCC on all targets. See <a href="Pragmas.html#Pragmas">Pragmas Accepted by GCC</a>, for details of target-specific pragmas. <li><cite>The definitions for </cite><code>__DATE__</code><cite> and </cite><code>__TIME__</code><cite> when respectively, the date and time of translation are not available (C90 6.8.8, C99 6.10.8, C11 6.10.8.1).</cite> </ul> </body></html>