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3 年之前
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  61. <a name="Identifiers"></a>
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  67. <a name="Identifiers-1"></a>
  68. <h4 class="subsection">11.2.2 Identifiers</h4>
  69. <a name="index-identifier"></a>
  70. <a name="index-name"></a>
  71. <a name="index-IDENTIFIER_005fNODE"></a>
  72. <p>An <code>IDENTIFIER_NODE</code> represents a slightly more general concept
  73. than the standard C or C++ concept of identifier. In particular, an
  74. <code>IDENTIFIER_NODE</code> may contain a &lsquo;<samp>$</samp>&rsquo;, or other extraordinary
  75. characters.
  76. </p>
  77. <p>There are never two distinct <code>IDENTIFIER_NODE</code>s representing the
  78. same identifier. Therefore, you may use pointer equality to compare
  79. <code>IDENTIFIER_NODE</code>s, rather than using a routine like
  80. <code>strcmp</code>. Use <code>get_identifier</code> to obtain the unique
  81. <code>IDENTIFIER_NODE</code> for a supplied string.
  82. </p>
  83. <p>You can use the following macros to access identifiers:
  84. </p><dl compact="compact">
  85. <dt><code>IDENTIFIER_POINTER</code>
  86. <a name="index-IDENTIFIER_005fPOINTER"></a>
  87. </dt>
  88. <dd><p>The string represented by the identifier, represented as a
  89. <code>char*</code>. This string is always <code>NUL</code>-terminated, and contains
  90. no embedded <code>NUL</code> characters.
  91. </p>
  92. </dd>
  93. <dt><code>IDENTIFIER_LENGTH</code>
  94. <a name="index-IDENTIFIER_005fLENGTH"></a>
  95. </dt>
  96. <dd><p>The length of the string returned by <code>IDENTIFIER_POINTER</code>, not
  97. including the trailing <code>NUL</code>. This value of
  98. <code>IDENTIFIER_LENGTH (x)</code> is always the same as <code>strlen
  99. (IDENTIFIER_POINTER (x))</code>.
  100. </p>
  101. </dd>
  102. <dt><code>IDENTIFIER_OPNAME_P</code>
  103. <a name="index-IDENTIFIER_005fOPNAME_005fP"></a>
  104. </dt>
  105. <dd><p>This predicate holds if the identifier represents the name of an
  106. overloaded operator. In this case, you should not depend on the
  107. contents of either the <code>IDENTIFIER_POINTER</code> or the
  108. <code>IDENTIFIER_LENGTH</code>.
  109. </p>
  110. </dd>
  111. <dt><code>IDENTIFIER_TYPENAME_P</code>
  112. <a name="index-IDENTIFIER_005fTYPENAME_005fP"></a>
  113. </dt>
  114. <dd><p>This predicate holds if the identifier represents the name of a
  115. user-defined conversion operator. In this case, the <code>TREE_TYPE</code> of
  116. the <code>IDENTIFIER_NODE</code> holds the type to which the conversion
  117. operator converts.
  118. </p>
  119. </dd>
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