Syntax Extensions (Using the GNU Compiler Collection (GCC)) (original) (raw)

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6.12 Other Extensions to C Syntax ¶

GNU C has traditionally supported numerous extensions to standard C syntax. Some of these features were originally intended for compatibility with other compilers or to ease traditional C compatibility, some have been adopted into subsequent versions of the C and/or C++ standards, while others remain specific to GNU C.

• Statements and Declarations in Expressions
• Locally Declared Labels
• Labels as Values
• Nested Functions
• Referring to a Type with typeof
• Support for offsetof
• Determining the Alignment of Functions, Types or Variables
• Extensions to enum Type Declarations
• Support for the _Bool Type
• Macros with a Variable Number of Arguments.
• Conditionals with Omitted Operands
• Case Ranges
• Mixed Declarations, Labels and Code
• C++ Style Comments
• Slightly Looser Rules for Escaped Newlines
• Hex Floats
• Binary Constants using the ‘0b’ Prefix
• Dollar Signs in Identifier Names
• The Character ESC in Constants
• Raw String Literals
• Alternate Keywords
• Function Names as Strings