1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- Copyright (C) 1988-2021 Free Software Foundation, Inc. 4 5Permission is granted to copy, distribute and/or modify this document 6under the terms of the GNU Free Documentation License, Version 1.3 or 7any later version published by the Free Software Foundation; with the 8Invariant Sections being "Free Software" and "Free Software Needs 9Free Documentation", with the Front-Cover Texts being "A GNU Manual," 10and with the Back-Cover Texts as in (a) below. 11 12(a) The FSF's Back-Cover Text is: "You are free to copy and modify 13this GNU Manual. 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Currently, 83<small>GDB</small> works best when debugging C<tt>++</tt> code that is compiled 84with the most recent version of <small>GCC</small> possible. The DWARF 85debugging format is preferred; <small>GCC</small> defaults to this on most 86popular platforms. Other compilers and/or debug formats are likely to 87work badly or not at all when using <small>GDB</small> to debug C<tt>++</tt> 88code. See <a href="Compilation.html#Compilation">Compilation</a>. 89</p></blockquote> 90 91<ol> 92<li> <a name="index-member-functions"></a> 93Member function calls are allowed; you can use expressions like 94 95<div class="smallexample"> 96<pre class="smallexample">count = aml->GetOriginal(x, y) 97</pre></div> 98 99</li><li> <a name="index-this_002c-inside-C_002b_002b-member-functions"></a> 100<a name="index-namespace-in-C_002b_002b"></a> 101While a member function is active (in the selected stack frame), your 102expressions have the same namespace available as the member function; 103that is, <small>GDB</small> allows implicit references to the class instance 104pointer <code>this</code> following the same rules as C<tt>++</tt>. <code>using</code> 105declarations in the current scope are also respected by <small>GDB</small>. 106 107</li><li> <a name="index-call-overloaded-functions"></a> 108<a name="index-overloaded-functions_002c-calling"></a> 109<a name="index-type-conversions-in-C_002b_002b"></a> 110You can call overloaded functions; <small>GDB</small> resolves the function 111call to the right definition, with some restrictions. <small>GDB</small> does not 112perform overload resolution involving user-defined type conversions, 113calls to constructors, or instantiations of templates that do not exist 114in the program. It also cannot handle ellipsis argument lists or 115default arguments. 116 117<p>It does perform integral conversions and promotions, floating-point 118promotions, arithmetic conversions, pointer conversions, conversions of 119class objects to base classes, and standard conversions such as those of 120functions or arrays to pointers; it requires an exact match on the 121number of function arguments. 122</p> 123<p>Overload resolution is always performed, unless you have specified 124<code>set overload-resolution off</code>. See <a href="Debugging-C-Plus-Plus.html#Debugging-C-Plus-Plus"><small>GDB</small> Features for C<tt>++</tt></a>. 125</p> 126<p>You must specify <code>set overload-resolution off</code> in order to use an 127explicit function signature to call an overloaded function, as in 128</p><div class="smallexample"> 129<pre class="smallexample">p 'foo(char,int)'('x', 13) 130</pre></div> 131 132<p>The <small>GDB</small> command-completion facility can simplify this; 133see <a href="Completion.html#Completion">Command Completion</a>. 134</p> 135</li><li> <a name="index-reference-declarations"></a> 136<small>GDB</small> understands variables declared as C<tt>++</tt> lvalue or rvalue 137references; you can use them in expressions just as you do in C<tt>++</tt> 138source—they are automatically dereferenced. 139 140<p>In the parameter list shown when <small>GDB</small> displays a frame, the values of 141reference variables are not displayed (unlike other variables); this 142avoids clutter, since references are often used for large structures. 143The <em>address</em> of a reference variable is always shown, unless 144you have specified ‘<samp>set print address off</samp>’. 145</p> 146</li><li> <small>GDB</small> supports the C<tt>++</tt> name resolution operator <code>::</code>—your 147expressions can use it just as expressions in your program do. Since 148one scope may be defined in another, you can use <code>::</code> repeatedly if 149necessary, for example in an expression like 150‘<samp><var>scope1</var>::<var>scope2</var>::<var>name</var></samp>’. <small>GDB</small> also allows 151resolving name scope by reference to source files, in both C and C<tt>++</tt> 152debugging (see <a href="Variables.html#Variables">Program Variables</a>). 153 154</li><li> <small>GDB</small> performs argument-dependent lookup, following the C<tt>++</tt> 155specification. 156</li></ol> 157 158<hr> 159<div class="header"> 160<p> 161Next: <a href="C-Defaults.html#C-Defaults" accesskey="n" rel="next">C Defaults</a>, Previous: <a href="C-Constants.html#C-Constants" accesskey="p" rel="previous">C Constants</a>, Up: <a href="C.html#C" accesskey="u" rel="up">C</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> 162</div> 163 164 165 166</body> 167</html> 168