Declarations

 Declarations specify the functions and variables referenced in a
 program.  Declarations in C have the following syntax:

       declaration:

          declaration-specifiers [init-declarator-list];

       declaration-specifiers:

          storage-class-specifier [declaration-specifiers]
          type-specifier [declaration-specifiers]
          type-qualifier [declaration-specifiers]

       init-declarator-list:

          init-declarator
          init-declarator-list, init-declarator

       init-declarator:

          declarator
          declarator = initializer

 Note the following items about the general syntax of a declaration:

  o  The storage-class-specifier, type-qualifier, and type-specifier
     can be listed in any order.  All are optional, but, except for
     function declarations, at least one such specifier or qualifier
     must be present.  Placing the storage-class-specifier anywhere
     but at the beginning of the declaration is an obsolete style.

  o  Storage-class keywords are auto, static, extern, and register.

  o  Type qualifiers are const, volatile, __restrict, and
     __unaligned.

  o  The declarator is the name of the object being declared.  A
     declarator can be as simple as a single identifier, or can be a
     complex construction declaring an array, structure, pointer,
     union, or function (such as *x, tree(), and treebar[10]).

  o  Initializers are optional and provide the initial value of an
     object.  An initializer can be a single value or a
     brace-enclosed list of values, depending on the type of object
     being declared.

  o  A declaration determines the beginning of an identifier's
     scope.

  o  An identifier's linkage is determined by the declaration's
     placement and its specified storage class.

 Consider the following example:

      volatile static int var_number = 10;

This declaration shows a qualified type (a type, int, with a type
qualifier, volatile), a storage class (static), a declarator (data),
and an initializer (10).  This declaration is also a definition,
because storage is reserved for the data object var_number.

For more information, see HELP CC LANGUAGE_TOPICS DATA_TYPES, HELP
CC LANGUAGE_TOPICS STORAGE_CLASSES, and HELP CC LANGUAGE_TOPICS
TYPE_QUALIFIERS.

Additional information available:

Interpretation