6.7 Declarations

• 6.7.1 Storage-class specifiers
• 6.7.2 Type specifiers
  • 6.7.2.1 Structure and union specifiers
  • 6.7.2.2 Enumeration specifiers
  • 6.7.2.3 Tags
• 6.7.3 Type qualifiers
  • 6.7.3.1 Formal definition of restrict
• 6.7.4 Function specifiers
• 6.7.5 Declarators
  • 6.7.5.1 Pointer declarators
  • 6.7.5.2 Array declarators
  • 6.7.5.3 Function declarators (including prototypes)
• 6.7.6 Type names
• 6.7.7 Type definitions
• 6.7.8 Initialization

Syntax

1

declaration:

declaration-specifiers init-declarator-listopt ;

declaration-specifiers:

storage-class-specifier declaration-specifiersopt

type-specifier declaration-specifiersopt

type-qualifier declaration-specifiersopt

function-specifier declaration-specifiersopt

init-declarator-list:

init-declarator

init-declarator-list , init-declarator

init-declarator:

declarator

declarator = initializer

Constraints

2

A declaration shall declare at least a declarator (other than the parameters of a function or the members of a structure or union), a tag, or the members of an enumeration.

3

If an identifier has no linkage, there shall be no more than one declaration of the identifier (in a declarator or type specifier) with the same scope and in the same name space, except for tags as specified in 6.7.2.3.

4

All declarations in the same scope that refer to the same object or function shall specify compatible types.

Semantics

5

A declaration specifies the interpretation and attributes of a set of identifiers. A definition of an identifier is a declaration for that identifier that:

• for an object, causes storage to be reserved for that object;

• for a function, includes the function body;[1]

• for an enumeration constant or typedef name, is the (only) declaration of the identifier.

6

The declaration specifiers consist of a sequence of specifiers that indicate the linkage, storage duration, and part of the type of the entities that the declarators denote. The init- declarator-list is a comma-separated sequence of declarators, each of which may have additional type information, or an initializer, or both. The declarators contain the identifiers (if any) being declared.

7

If an identifier for an object is declared with no linkage, the type for the object shall be complete by the end of its declarator, or by the end of its init-declarator if it has an initializer; in the case of function parameters (including in prototypes), it is the adjusted type (see 6.7.5.3) that is required to be complete.

Forward References

6.7.5 Declarators 6.7.2.2 Enumeration specifiers

6.7.8 Initialization

Footnotes

[1]

Function definitions have a different syntax, described in 6.9.1.