C++ expressions

GDB expression handling can interpret most C++ expressions.

Warning: GDB can only debug C++ code if you use the proper compiler. Typically, C++ debugging depends on the use of additional debugging information in the symbol table, and thus requires special support. In particular, if your compiler generates a.out, MIPS ECOFF, RS/6000 XCOFF, or ELF with stabs extensions to the symbol table, these facilities are all available. (With GNU CC, you can use the `-gstabs' option to request stabs debugging extensions explicitly.) Where the object code format is standard COFF or DWARF in ELF, on the other hand, most of the C++ support in GDB does not work.

1. Member function calls are allowed; you can use expressions like

   count = aml->GetOriginal(x, y)
   

2. While a member function is active (in the selected stack frame), your expressions have the same namespace available as the member function; that is, GDB allows implicit references to the class instance pointer this following the same rules as C++.
3. You can call overloaded functions; GDB resolves the function call to the right definition, with one restriction--you must use arguments of the type required by the function that you want to call. GDB does not perform conversions requiring constructors or user-defined type operators.
4. GDB understands variables declared as C++ references; you can use them in expressions just as you do in C++ source--they are automatically dereferenced. In the parameter list shown when GDB displays a frame, the values of reference variables are not displayed (unlike other variables); this avoids clutter, since references are often used for large structures. The address of a reference variable is always shown, unless you have specified `set print address off'.
5. GDB supports the C++ name resolution operator ::---your expressions can use it just as expressions in your program do. Since one scope may be defined in another, you can use :: repeatedly if necessary, for example in an expression like `scope1::scope2::name'. GDB also allows resolving name scope by reference to source files, in both C and C++ debugging (see section Program variables).

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