Vax C90-EL SERIES Service Manual download pdf (Page 184)

Cray Standard C/C++ Reference Manual

• enum tags can be incomplete as long as the tag name is defined and resolved

by specifying the brace-enclosed list later.

• An extra comma is allowed at the end of an enum list.

• The final semicolon preceding the closing of a struct or union type

specifier can be omitted.

• A label definition can be immediately followed by a right brace ( } ).

(Normally, a statement must follow a label definition.)

• An empty declaration (a semicolon preceded by nothing) is allowed.

• An initializer expression that is a single value and is used to initialize an

entire static array, struct, or union does not need to be enclosed in braces.

ANSI C requires braces.

• In an initializer, a pointer constant value can be cast to an integral type if the

integral type is large enough to contain it.

• The address of a variable with register storage class may be taken.

• In an integral constant expression, an integer constant can be cast to a pointer

type and then back to an integral type.

• In duplicate size and sign specifiers (for example, short short or

unsigned unsigned) the redundancy is ignored.

• Benign redeclarations of typedef names are allowed. That is, a typedef

name can be redeclared in the same scope with the same type.

• Dollar sign ($) and at sign (@) characters can be accepted in identifiers

by using the -h calchars command line option. This is not allowed by

default.

• Numbers are scanned according to the syntax for numbers rather than the

pp-number syntax. Thus, 0x123e+1 is scanned as three tokens instead

of one token that is not valid. If the -h conform option is specified, the

pp-number syntax is used.

• Assignment and pointer differences are allowed between pointers to types

that are interchangeable but not identical, for example, unsigned char *

and char *. This includes pointers to integral types of the same size (for

example, int * and long *). Assignment of a string constant to a pointer to

any kind of character is allowed without a warning.

• Assignment of pointer types is allowed in cases where the destination type

has added type qualifiers that are not at the top level (for example, int **

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Vax C90-EL SERIES Service Manual Page 184