<html lang="en"> <head> <title>Deprecated Features - 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_002b_002b-Extensions.html#C_002b_002b-Extensions" title="C++ Extensions"> <link rel="prev" href="Java-Exceptions.html#Java-Exceptions" title="Java Exceptions"> <link rel="next" href="Backwards-Compatibility.html#Backwards-Compatibility" title="Backwards Compatibility"> <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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Now that the C++ standard is complete, some of those features are superseded by superior alternatives. Using the old features might cause a warning in some cases that the feature will be dropped in the future. In other cases, the feature might be gone already. <p>While the list below is not exhaustive, it documents some of the options that are now deprecated: <dl> <dt><code>-fexternal-templates</code><dt><code>-falt-external-templates</code><dd>These are two of the many ways for G++ to implement template instantiation. See <a href="Template-Instantiation.html#Template-Instantiation">Template Instantiation</a>. The C++ standard clearly defines how template definitions have to be organized across implementation units. G++ has an implicit instantiation mechanism that should work just fine for standard-conforming code. <br><dt><code>-fstrict-prototype</code><dt><code>-fno-strict-prototype</code><dd>Previously it was possible to use an empty prototype parameter list to indicate an unspecified number of parameters (like C), rather than no parameters, as C++ demands. This feature has been removed, except where it is required for backwards compatibility. See <a href="Backwards-Compatibility.html#Backwards-Compatibility">Backwards Compatibility</a>. </dl> <p>G++ allows a virtual function returning ‘<samp><span class="samp">void *</span></samp>’ to be overridden by one returning a different pointer type. This extension to the covariant return type rules is now deprecated and will be removed from a future version. <p>The G++ minimum and maximum operators (‘<samp><span class="samp"><?</span></samp>’ and ‘<samp><span class="samp">>?</span></samp>’) and their compound forms (‘<samp><span class="samp"><?=</span></samp>’) and ‘<samp><span class="samp">>?=</span></samp>’) have been deprecated and are now removed from G++. Code using these operators should be modified to use <code>std::min</code> and <code>std::max</code> instead. <p>The named return value extension has been deprecated, and is now removed from G++. <p>The use of initializer lists with new expressions has been deprecated, and is now removed from G++. <p>Floating and complex non-type template parameters have been deprecated, and are now removed from G++. <p>The implicit typename extension has been deprecated and is now removed from G++. <p>The use of default arguments in function pointers, function typedefs and other places where they are not permitted by the standard is deprecated and will be removed from a future version of G++. <p>G++ allows floating-point literals to appear in integral constant expressions, e.g. ‘<samp><span class="samp"> enum E { e = int(2.2 * 3.7) } </span></samp>’ This extension is deprecated and will be removed from a future version. <p>G++ allows static data members of const floating-point type to be declared with an initializer in a class definition. The standard only allows initializers for static members of const integral types and const enumeration types so this extension has been deprecated and will be removed from a future version. </body></html>