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  61. <a name="Deprecated-Features"></a>
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  67. <a name="Deprecated-Features-1"></a>
  68. <h3 class="section">7.11 Deprecated Features</h3>
  69. <p>In the past, the GNU C++ compiler was extended to experiment with new
  70. features, at a time when the C++ language was still evolving. Now that
  71. the C++ standard is complete, some of those features are superseded by
  72. superior alternatives. Using the old features might cause a warning in
  73. some cases that the feature will be dropped in the future. In other
  74. cases, the feature might be gone already.
  75. </p>
  76. <p>G++ allows a virtual function returning &lsquo;<samp>void *</samp>&rsquo; to be overridden
  77. by one returning a different pointer type. This extension to the
  78. covariant return type rules is now deprecated and will be removed from a
  79. future version.
  80. </p>
  81. <p>The use of default arguments in function pointers, function typedefs
  82. and other places where they are not permitted by the standard is
  83. deprecated and will be removed from a future version of G++.
  84. </p>
  85. <p>G++ allows floating-point literals to appear in integral constant expressions,
  86. e.g. &lsquo;<samp> enum E { e = int(2.2 * 3.7) } </samp>&rsquo;
  87. This extension is deprecated and will be removed from a future version.
  88. </p>
  89. <p>G++ allows static data members of const floating-point type to be declared
  90. with an initializer in a class definition. The standard only allows
  91. initializers for static members of const integral types and const
  92. enumeration types so this extension has been deprecated and will be removed
  93. from a future version.
  94. </p>
  95. <p>G++ allows attributes to follow a parenthesized direct initializer,
  96. e.g. &lsquo;<samp> int f (0) __attribute__ ((something)); </samp>&rsquo; This extension
  97. has been ignored since G++ 3.3 and is deprecated.
  98. </p>
  99. <p>G++ allows anonymous structs and unions to have members that are not
  100. public non-static data members (i.e. fields). These extensions are
  101. deprecated.
  102. </p>
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