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    60. 

  60. <h1 class="settitle" align="center">The C Preprocessor</h1>
    61. 

  61. 

  62. 

  63. 

  64. 

  65. 

  66. 

  67. 

  68. 

  69. 

  70. 

  71. 

  72. 

  73. 

  74. 

  75. 

  76. <span id="SEC_Contents"></span>
    77. 

  77. <h2 class="contents-heading">Table of Contents</h2>
    78. 

  78. 

  79. <div class="contents">
    80. 

  80. 

  81. <ul class="no-bullet">
    82. 

  82.   <li><a id="toc-Overview-1" href="Overview.html#Overview">1 Overview</a>
    83. 

  83.   <ul class="no-bullet">
    84. 

  84.     <li><a id="toc-Character-sets-1" href="Character-sets.html#Character-sets">1.1 Character sets</a></li>
    85. 

  85.     <li><a id="toc-Initial-processing-1" href="Initial-processing.html#Initial-processing">1.2 Initial processing</a></li>
    86. 

  86.     <li><a id="toc-Tokenization-1" href="Tokenization.html#Tokenization">1.3 Tokenization</a></li>
    87. 

  87.     <li><a id="toc-The-preprocessing-language-1" href="The-preprocessing-language.html#The-preprocessing-language">1.4 The preprocessing language</a></li>
    88. 

  88.   </ul></li>
    89. 

  89.   <li><a id="toc-Header-Files-1" href="Header-Files.html#Header-Files">2 Header Files</a>
    90. 

  90.   <ul class="no-bullet">
    91. 

  91.     <li><a id="toc-Include-Syntax-1" href="Include-Syntax.html#Include-Syntax">2.1 Include Syntax</a></li>
    92. 

  92.     <li><a id="toc-Include-Operation-1" href="Include-Operation.html#Include-Operation">2.2 Include Operation</a></li>
    93. 

  93.     <li><a id="toc-Search-Path-1" href="Search-Path.html#Search-Path">2.3 Search Path</a></li>
    94. 

  94.     <li><a id="toc-Once_002dOnly-Headers-1" href="Once_002dOnly-Headers.html#Once_002dOnly-Headers">2.4 Once-Only Headers</a></li>
    95. 

  95.     <li><a id="toc-Alternatives-to-Wrapper-_0023ifndef-1" href="Alternatives-to-Wrapper-_0023ifndef.html#Alternatives-to-Wrapper-_0023ifndef">2.5 Alternatives to Wrapper #ifndef</a></li>
    96. 

  96.     <li><a id="toc-Computed-Includes-1" href="Computed-Includes.html#Computed-Includes">2.6 Computed Includes</a></li>
    97. 

  97.     <li><a id="toc-Wrapper-Headers-1" href="Wrapper-Headers.html#Wrapper-Headers">2.7 Wrapper Headers</a></li>
    98. 

  98.     <li><a id="toc-System-Headers-1" href="System-Headers.html#System-Headers">2.8 System Headers</a></li>
    99. 

  99.   </ul></li>
    100. 

  100.   <li><a id="toc-Macros-1" href="Macros.html#Macros">3 Macros</a>
    101. 

  101.   <ul class="no-bullet">
    102. 

  102.     <li><a id="toc-Object_002dlike-Macros-1" href="Object_002dlike-Macros.html#Object_002dlike-Macros">3.1 Object-like Macros</a></li>
    103. 

  103.     <li><a id="toc-Function_002dlike-Macros-1" href="Function_002dlike-Macros.html#Function_002dlike-Macros">3.2 Function-like Macros</a></li>
    104. 

  104.     <li><a id="toc-Macro-Arguments-1" href="Macro-Arguments.html#Macro-Arguments">3.3 Macro Arguments</a></li>
    105. 

  105.     <li><a id="toc-Stringizing-1" href="Stringizing.html#Stringizing">3.4 Stringizing</a></li>
    106. 

  106.     <li><a id="toc-Concatenation-1" href="Concatenation.html#Concatenation">3.5 Concatenation</a></li>
    107. 

  107.     <li><a id="toc-Variadic-Macros-1" href="Variadic-Macros.html#Variadic-Macros">3.6 Variadic Macros</a></li>
    108. 

  108.     <li><a id="toc-Predefined-Macros-1" href="Predefined-Macros.html#Predefined-Macros">3.7 Predefined Macros</a>
    109. 

  109.     <ul class="no-bullet">
    110. 

  110.       <li><a id="toc-Standard-Predefined-Macros-1" href="Standard-Predefined-Macros.html#Standard-Predefined-Macros">3.7.1 Standard Predefined Macros</a></li>
    111. 

  111.       <li><a id="toc-Common-Predefined-Macros-1" href="Common-Predefined-Macros.html#Common-Predefined-Macros">3.7.2 Common Predefined Macros</a></li>
    112. 

  112.       <li><a id="toc-System_002dspecific-Predefined-Macros-1" href="System_002dspecific-Predefined-Macros.html#System_002dspecific-Predefined-Macros">3.7.3 System-specific Predefined Macros</a></li>
    113. 

  113.       <li><a id="toc-C_002b_002b-Named-Operators-1" href="C_002b_002b-Named-Operators.html#C_002b_002b-Named-Operators">3.7.4 C++ Named Operators</a></li>
    114. 

  114.     </ul></li>
    115. 

  115.     <li><a id="toc-Undefining-and-Redefining-Macros-1" href="Undefining-and-Redefining-Macros.html#Undefining-and-Redefining-Macros">3.8 Undefining and Redefining Macros</a></li>
    116. 

  116.     <li><a id="toc-Directives-Within-Macro-Arguments-1" href="Directives-Within-Macro-Arguments.html#Directives-Within-Macro-Arguments">3.9 Directives Within Macro Arguments</a></li>
    117. 

  117.     <li><a id="toc-Macro-Pitfalls-1" href="Macro-Pitfalls.html#Macro-Pitfalls">3.10 Macro Pitfalls</a>
    118. 

  118.     <ul class="no-bullet">
    119. 

  119.       <li><a id="toc-Misnesting-1" href="Misnesting.html#Misnesting">3.10.1 Misnesting</a></li>
    120. 

  120.       <li><a id="toc-Operator-Precedence-Problems-1" href="Operator-Precedence-Problems.html#Operator-Precedence-Problems">3.10.2 Operator Precedence Problems</a></li>
    121. 

  121.       <li><a id="toc-Swallowing-the-Semicolon-1" href="Swallowing-the-Semicolon.html#Swallowing-the-Semicolon">3.10.3 Swallowing the Semicolon</a></li>
    122. 

  122.       <li><a id="toc-Duplication-of-Side-Effects-1" href="Duplication-of-Side-Effects.html#Duplication-of-Side-Effects">3.10.4 Duplication of Side Effects</a></li>
    123. 

  123.       <li><a id="toc-Self_002dReferential-Macros-1" href="Self_002dReferential-Macros.html#Self_002dReferential-Macros">3.10.5 Self-Referential Macros</a></li>
    124. 

  124.       <li><a id="toc-Argument-Prescan-1" href="Argument-Prescan.html#Argument-Prescan">3.10.6 Argument Prescan</a></li>
    125. 

  125.       <li><a id="toc-Newlines-in-Arguments-1" href="Newlines-in-Arguments.html#Newlines-in-Arguments">3.10.7 Newlines in Arguments</a></li>
    126. 

  126.     </ul></li>
    127. 

  127.   </ul></li>
    128. 

  128.   <li><a id="toc-Conditionals-1" href="Conditionals.html#Conditionals">4 Conditionals</a>
    129. 

  129.   <ul class="no-bullet">
    130. 

  130.     <li><a id="toc-Conditional-Uses-1" href="Conditional-Uses.html#Conditional-Uses">4.1 Conditional Uses</a></li>
    131. 

  131.     <li><a id="toc-Conditional-Syntax-1" href="Conditional-Syntax.html#Conditional-Syntax">4.2 Conditional Syntax</a>
    132. 

  132.     <ul class="no-bullet">
    133. 

  133.       <li><a id="toc-Ifdef-1" href="Ifdef.html#Ifdef">4.2.1 Ifdef</a></li>
    134. 

  134.       <li><a id="toc-If-1" href="If.html#If">4.2.2 If</a></li>
    135. 

  135.       <li><a id="toc-Defined-1" href="Defined.html#Defined">4.2.3 Defined</a></li>
    136. 

  136.       <li><a id="toc-Else-1" href="Else.html#Else">4.2.4 Else</a></li>
    137. 

  137.       <li><a id="toc-Elif-1" href="Elif.html#Elif">4.2.5 Elif</a></li>
    138. 

  138.       <li><a id="toc-_005f_005fhas_005fattribute-1" href="_005f_005fhas_005fattribute.html#g_t_005f_005fhas_005fattribute">4.2.6 <code>__has_attribute</code></a></li>
    139. 

  139.       <li><a id="toc-_005f_005fhas_005fcpp_005fattribute-1" href="_005f_005fhas_005fcpp_005fattribute.html#g_t_005f_005fhas_005fcpp_005fattribute">4.2.7 <code>__has_cpp_attribute</code></a></li>
    140. 

  140.       <li><a id="toc-_005f_005fhas_005fc_005fattribute-1" href="_005f_005fhas_005fc_005fattribute.html#g_t_005f_005fhas_005fc_005fattribute">4.2.8 <code>__has_c_attribute</code></a></li>
    141. 

  141.       <li><a id="toc-_005f_005fhas_005fbuiltin-1" href="_005f_005fhas_005fbuiltin.html#g_t_005f_005fhas_005fbuiltin">4.2.9 <code>__has_builtin</code></a></li>
    142. 

  142.       <li><a id="toc-_005f_005fhas_005finclude-1" href="_005f_005fhas_005finclude.html#g_t_005f_005fhas_005finclude">4.2.10 <code>__has_include</code></a></li>
    143. 

  143.     </ul></li>
    144. 

  144.     <li><a id="toc-Deleted-Code-1" href="Deleted-Code.html#Deleted-Code">4.3 Deleted Code</a></li>
    145. 

  145.   </ul></li>
    146. 

  146.   <li><a id="toc-Diagnostics-1" href="Diagnostics.html#Diagnostics">5 Diagnostics</a></li>
    147. 

  147.   <li><a id="toc-Line-Control-1" href="Line-Control.html#Line-Control">6 Line Control</a></li>
    148. 

  148.   <li><a id="toc-Pragmas-1" href="Pragmas.html#Pragmas">7 Pragmas</a></li>
    149. 

  149.   <li><a id="toc-Other-Directives-1" href="Other-Directives.html#Other-Directives">8 Other Directives</a></li>
    150. 

  150.   <li><a id="toc-Preprocessor-Output-1" href="Preprocessor-Output.html#Preprocessor-Output">9 Preprocessor Output</a></li>
    151. 

  151.   <li><a id="toc-Traditional-Mode-1" href="Traditional-Mode.html#Traditional-Mode">10 Traditional Mode</a>
    152. 

  152.   <ul class="no-bullet">
    153. 

  153.     <li><a id="toc-Traditional-lexical-analysis-1" href="Traditional-lexical-analysis.html#Traditional-lexical-analysis">10.1 Traditional lexical analysis</a></li>
    154. 

  154.     <li><a id="toc-Traditional-macros-1" href="Traditional-macros.html#Traditional-macros">10.2 Traditional macros</a></li>
    155. 

  155.     <li><a id="toc-Traditional-miscellany-1" href="Traditional-miscellany.html#Traditional-miscellany">10.3 Traditional miscellany</a></li>
    156. 

  156.     <li><a id="toc-Traditional-warnings-1" href="Traditional-warnings.html#Traditional-warnings">10.4 Traditional warnings</a></li>
    157. 

  157.   </ul></li>
    158. 

  158.   <li><a id="toc-Implementation-Details-1" href="Implementation-Details.html#Implementation-Details">11 Implementation Details</a>
    159. 

  159.   <ul class="no-bullet">
    160. 

  160.     <li><a id="toc-Implementation_002ddefined-behavior-1" href="Implementation_002ddefined-behavior.html#Implementation_002ddefined-behavior">11.1 Implementation-defined behavior</a></li>
    161. 

  161.     <li><a id="toc-Implementation-limits-1" href="Implementation-limits.html#Implementation-limits">11.2 Implementation limits</a></li>
    162. 

  162.     <li><a id="toc-Obsolete-Features-1" href="Obsolete-Features.html#Obsolete-Features">11.3 Obsolete Features</a>
    163. 

  163.     <ul class="no-bullet">
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  164.       <li><a id="toc-Assertions" href="Obsolete-Features.html#Assertions">11.3.1 Assertions</a></li>
    165. 

  165.     </ul></li>
    166. 

  166.   </ul></li>
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  167.   <li><a id="toc-Invocation-1" href="Invocation.html#Invocation">12 Invocation</a></li>
    168. 

  168.   <li><a id="toc-Environment-Variables-1" href="Environment-Variables.html#Environment-Variables">13 Environment Variables</a></li>
    169. 

  169.   <li><a id="toc-GNU-Free-Documentation-License-1" href="GNU-Free-Documentation-License.html#GNU-Free-Documentation-License">GNU Free Documentation License</a>
    170. 

  170.   <ul class="no-bullet">
    171. 

  171.     <li><a id="toc-ADDENDUM_003a-How-to-use-this-License-for-your-documents" href="GNU-Free-Documentation-License.html#ADDENDUM_003a-How-to-use-this-License-for-your-documents">ADDENDUM: How to use this License for your documents</a></li>
    172. 

  172.   </ul></li>
    173. 

  173.   <li><a id="toc-Index-of-Directives-1" href="Index-of-Directives.html#Index-of-Directives" rel="index">Index of Directives</a></li>
    174. 

  174.   <li><a id="toc-Option-Index-1" href="Option-Index.html#Option-Index" rel="index">Option Index</a></li>
    175. 

  175.   <li><a id="toc-Concept-Index-1" href="Concept-Index.html#Concept-Index" rel="index">Concept Index</a></li>
    176. 

  176. </ul>
    177. 

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    178. 

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  182. Next: <a href="Overview.html" accesskey="n" rel="next">Overview</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html" title="Index" rel="index">Index</a>]</p>
    183. 

  183. </div>
    184. 

  184. <hr>
    185. 

  185. <span id="SEC_Top"></span><p>The C preprocessor implements the macro language used to transform C,
    186. 

  186. C++, and Objective-C programs before they are compiled.  It can also be
    187. 

  187. useful on its own.
    188. 

  188. </p>
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    196. 

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  219. </td></tr>
    220. 

  220. <tr><td align="left" valign="top">&bull; <a href="Option-Index.html" rel="index">Option Index</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    221. 

  221. </td></tr>
    222. 

  222. <tr><td align="left" valign="top">&bull; <a href="Concept-Index.html" rel="index">Concept Index</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    223. 

  223. </td></tr>
    224. 

  224. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    225. 

  225. 

  226. </pre></th></tr><tr><th colspan="3" align="left" valign="top"><pre class="menu-comment"> &mdash; The Detailed Node Listing &mdash;
    227. 

  227. 

  228. Overview
    229. 

  229. 

  230. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Character-sets.html">Character sets</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    231. 

  231. </td></tr>
    232. 

  232. <tr><td align="left" valign="top">&bull; <a href="Initial-processing.html">Initial processing</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    233. 

  233. </td></tr>
    234. 

  234. <tr><td align="left" valign="top">&bull; <a href="Tokenization.html">Tokenization</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    235. 

  235. </td></tr>
    236. 

  236. <tr><td align="left" valign="top">&bull; <a href="The-preprocessing-language.html">The preprocessing language</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    237. 

  237. </td></tr>
    238. 

  238. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    239. 

  239. 

  240. Header Files
    241. 

  241. 

  242. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Include-Syntax.html">Include Syntax</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    243. 

  243. </td></tr>
    244. 

  244. <tr><td align="left" valign="top">&bull; <a href="Include-Operation.html">Include Operation</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    245. 

  245. </td></tr>
    246. 

  246. <tr><td align="left" valign="top">&bull; <a href="Search-Path.html">Search Path</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    247. 

  247. </td></tr>
    248. 

  248. <tr><td align="left" valign="top">&bull; <a href="Once_002dOnly-Headers.html">Once-Only Headers</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    249. 

  249. </td></tr>
    250. 

  250. <tr><td align="left" valign="top">&bull; <a href="Alternatives-to-Wrapper-_0023ifndef.html">Alternatives to Wrapper #ifndef</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    251. 

  251. </td></tr>
    252. 

  252. <tr><td align="left" valign="top">&bull; <a href="Computed-Includes.html">Computed Includes</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    253. 

  253. </td></tr>
    254. 

  254. <tr><td align="left" valign="top">&bull; <a href="Wrapper-Headers.html">Wrapper Headers</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    255. 

  255. </td></tr>
    256. 

  256. <tr><td align="left" valign="top">&bull; <a href="System-Headers.html">System Headers</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    257. 

  257. </td></tr>
    258. 

  258. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    259. 

  259. 

  260. Macros
    261. 

  261. 

  262. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Object_002dlike-Macros.html">Object-like Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    263. 

  263. </td></tr>
    264. 

  264. <tr><td align="left" valign="top">&bull; <a href="Function_002dlike-Macros.html">Function-like Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    265. 

  265. </td></tr>
    266. 

  266. <tr><td align="left" valign="top">&bull; <a href="Macro-Arguments.html">Macro Arguments</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    267. 

  267. </td></tr>
    268. 

  268. <tr><td align="left" valign="top">&bull; <a href="Stringizing.html">Stringizing</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    269. 

  269. </td></tr>
    270. 

  270. <tr><td align="left" valign="top">&bull; <a href="Concatenation.html">Concatenation</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    271. 

  271. </td></tr>
    272. 

  272. <tr><td align="left" valign="top">&bull; <a href="Variadic-Macros.html">Variadic Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    273. 

  273. </td></tr>
    274. 

  274. <tr><td align="left" valign="top">&bull; <a href="Predefined-Macros.html">Predefined Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    275. 

  275. </td></tr>
    276. 

  276. <tr><td align="left" valign="top">&bull; <a href="Undefining-and-Redefining-Macros.html">Undefining and Redefining Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    277. 

  277. </td></tr>
    278. 

  278. <tr><td align="left" valign="top">&bull; <a href="Directives-Within-Macro-Arguments.html">Directives Within Macro Arguments</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    279. 

  279. </td></tr>
    280. 

  280. <tr><td align="left" valign="top">&bull; <a href="Macro-Pitfalls.html">Macro Pitfalls</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    281. 

  281. </td></tr>
    282. 

  282. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    283. 

  283. 

  284. Predefined Macros
    285. 

  285. 

  286. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Standard-Predefined-Macros.html">Standard Predefined Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    287. 

  287. </td></tr>
    288. 

  288. <tr><td align="left" valign="top">&bull; <a href="Common-Predefined-Macros.html">Common Predefined Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    289. 

  289. </td></tr>
    290. 

  290. <tr><td align="left" valign="top">&bull; <a href="System_002dspecific-Predefined-Macros.html">System-specific Predefined Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    291. 

  291. </td></tr>
    292. 

  292. <tr><td align="left" valign="top">&bull; <a href="C_002b_002b-Named-Operators.html">C++ Named Operators</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    293. 

  293. </td></tr>
    294. 

  294. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    295. 

  295. 

  296. Macro Pitfalls
    297. 

  297. 

  298. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Misnesting.html">Misnesting</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    299. 

  299. </td></tr>
    300. 

  300. <tr><td align="left" valign="top">&bull; <a href="Operator-Precedence-Problems.html">Operator Precedence Problems</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    301. 

  301. </td></tr>
    302. 

  302. <tr><td align="left" valign="top">&bull; <a href="Swallowing-the-Semicolon.html">Swallowing the Semicolon</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    303. 

  303. </td></tr>
    304. 

  304. <tr><td align="left" valign="top">&bull; <a href="Duplication-of-Side-Effects.html">Duplication of Side Effects</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    305. 

  305. </td></tr>
    306. 

  306. <tr><td align="left" valign="top">&bull; <a href="Self_002dReferential-Macros.html">Self-Referential Macros</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    307. 

  307. </td></tr>
    308. 

  308. <tr><td align="left" valign="top">&bull; <a href="Argument-Prescan.html">Argument Prescan</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    309. 

  309. </td></tr>
    310. 

  310. <tr><td align="left" valign="top">&bull; <a href="Newlines-in-Arguments.html">Newlines in Arguments</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    311. 

  311. </td></tr>
    312. 

  312. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    313. 

  313. 

  314. Conditionals
    315. 

  315. 

  316. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Conditional-Uses.html">Conditional Uses</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    317. 

  317. </td></tr>
    318. 

  318. <tr><td align="left" valign="top">&bull; <a href="Conditional-Syntax.html">Conditional Syntax</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    319. 

  319. </td></tr>
    320. 

  320. <tr><td align="left" valign="top">&bull; <a href="Deleted-Code.html">Deleted Code</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    321. 

  321. </td></tr>
    322. 

  322. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    323. 

  323. 

  324. Conditional Syntax
    325. 

  325. 

  326. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Ifdef.html">Ifdef</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    327. 

  327. </td></tr>
    328. 

  328. <tr><td align="left" valign="top">&bull; <a href="If.html">If</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    329. 

  329. </td></tr>
    330. 

  330. <tr><td align="left" valign="top">&bull; <a href="Defined.html">Defined</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    331. 

  331. </td></tr>
    332. 

  332. <tr><td align="left" valign="top">&bull; <a href="Else.html">Else</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    333. 

  333. </td></tr>
    334. 

  334. <tr><td align="left" valign="top">&bull; <a href="Elif.html">Elif</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    335. 

  335. </td></tr>
    336. 

  336. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    337. 

  337. 

  338. Implementation Details
    339. 

  339. 

  340. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Implementation_002ddefined-behavior.html">Implementation-defined behavior</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    341. 

  341. </td></tr>
    342. 

  342. <tr><td align="left" valign="top">&bull; <a href="Implementation-limits.html">Implementation limits</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    343. 

  343. </td></tr>
    344. 

  344. <tr><td align="left" valign="top">&bull; <a href="Obsolete-Features.html">Obsolete Features</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    345. 

  345. </td></tr>
    346. 

  346. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    347. 

  347. 

  348. Obsolete Features
    349. 

  349. 

  350. </pre></th></tr><tr><td align="left" valign="top">&bull; <a href="Obsolete-Features.html">Obsolete Features</a></td><td>&nbsp;&nbsp;</td><td align="left" valign="top">
    351. 

  351. </td></tr>
    352. 

  352. <tr><th colspan="3" align="left" valign="top"><pre class="menu-comment">
    353. 

  353. 

  354. </pre></th></tr></table>
    355. 

  355. 

  356. <p>Copyright &copy; 1987-2023 Free Software Foundation, Inc.
    357. 

  357. </p>
    358. 

  358. <p>Permission is granted to copy, distribute and/or modify this document
    359. 

  359. under the terms of the GNU Free Documentation License, Version 1.3 or
    360. 

  360. any later version published by the Free Software Foundation.  A copy of
    361. 

  361. the license is included in the
    362. 

  362. section entitled &ldquo;GNU Free Documentation License&rdquo;.
    363. 

  363. </p>
    364. 

  364. <p>This manual contains no Invariant Sections.  The Front-Cover Texts are
    365. 

  365. (a) (see below), and the Back-Cover Texts are (b) (see below).
    366. 

  366. </p>
    367. 

  367. <p>(a) The FSF&rsquo;s Front-Cover Text is:
    368. 

  368. </p>
    369. 

  369. <p>A GNU Manual
    370. 

  370. </p>
    371. 

  371. <p>(b) The FSF&rsquo;s Back-Cover Text is:
    372. 

  372. </p>
    373. 

  373. <p>You have freedom to copy and modify this GNU Manual, like GNU
    374. 

  374.      software.  Copies published by the Free Software Foundation raise
    375. 

  375.      funds for GNU development.
    376. 

  376. </p>
    377. 

  377. <hr>
    378. 

  378. <div class="header">
    379. 

  379. <p>
    380. 

  380. Next: <a href="Overview.html" accesskey="n" rel="next">Overview</a> &nbsp; [<a href="#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index-of-Directives.html" title="Index" rel="index">Index</a>]</p>
    381. 

  381. </div>
    382. 

  382. 

  383. 

  384. 

  385. </body>
    386. 

  386. </html>
    387.