Deprecated Features (Using the GNU Compiler Collection (GCC))

### 8.10 Deprecated Features ¶

In the past, the GNU C++ compiler was extended to experiment with new features, at a time when the C++ language was still evolving. Now that the C++ standard is complete, some of those features are superseded by superior alternatives.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.

G++ allows a virtual function returning ‘`void *`’ 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.

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++.

G++ allows attributes to follow a parenthesized direct initializer, e.g. ‘`int f (0) __attribute__ ((something));` ’ This extension has been ignored since G++ 3.3 and is deprecated.

G++ allows anonymous structs and unions to have members that are not public non-static data members (i.e. fields). These extensions are deprecated.