Extensions for GNU C compatibility

The following features are enabled with the LANGLVL(*EXTENDED) option, which is the default language level. For more information, see the LANGLVL option in the ILE C/C++ Compiler Reference.

Table 1. Default ILE C++ extensions for compatibility with GNU C
Language feature	Discussed in:
Placement of flexible array members anywhere in structure or union	Flexible array members
Static initialization of flexible array members of aggregates	Flexible array members
`__alignof__` operator	The __alignof__ operator
`__typeof__` operator	The __typeof__ operator
Generalized lvalues	Lvalues and rvalues
Function attributes	Function attributes
`#include_next` preprocessor directive	The #include_next directive
Alternate keywords	Keywords for language extensions
`__extension__` keyword	Keywords for language extensions
Type attributes	Type attributes
Variable attributes	Variable attributes
Zero-extent arrays	Zero-extent array members
Variadic macro extensions	Variadic macro extensions
`#warning` preprocessor directive	The #warning directive
`#assert`, `#unassert` preprocessor directives	Assertion directives

The following feature requires compilation with the use of an additional option.

Table 2. ILE C++ extensions for GNU C compatibility, requiring additional compiler options
Language feature	Discussed in:
Dollar signs in identifiers	Characters in identifiers