Tham khảo tài liệu 'the new c standard- p8', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Keywords 788 785 EXAMPLE 1 The program fragment 1Ex is parsed as a preprocessing number token one that is not a valid floating or integer constant token even though a parse as the pair of preprocessing tokens 1 and Ex might produce a valid expression for example if Ex were a macro defined as 1 . Similarly the program fragment 1E1 is parsed as a preprocessing number one that is a valid floating constant token whether or not E is a macro name. Commentary Standard C specifies a token-based preprocessor. The original K R preprocessor specification could be interpreted as a token-based or character-based preprocessor. In a character-based preprocessor wherever a character sequence occurs even within string literals and character constants if it matches the name of a macro it will be substituted for. 786 EXAMPLE 2 The program fragment x y is parsed as x y which violates a constraint on increment operators even though the parse x y might yield a correct expression. EXAMPLE 787 Forward references character constants comments expressions floating constants header names macro replacement postfix increment and decrement operators prefix increment and decrement operators preprocessing directives preprocessing numbers string literals . Keywords 788 keyword one of auto enum restrict unsigned break extern return void case float short volatile char for signed while const goto sizeof _Bool continue if static -Complex default inline struct _Imaginary do int switch double long typedef else register union Commentary I Kii txtrr n c f amo oti 4 ttaI r 4 I wiara Tir it in tli Roon rlopnmAnf I Kzi i 4 ti fi am vut iimc tvxc iiT wii l 1 x7 1 base dCOu-The keywords const arid volatile were not in the uase document. The identifier entry was reserved ny ment the base document but the functionality suggested by its name Fortran-style multiple entry points into a function was never introduced into C. The .