The rest of this section describes the form and meaning of declarations for variable types summarized in this list. In particular, the remaining sections explain how to declare the following:
Type of Variable |
Description |
|---|---|
Single-value variables with integral or floating-point type |
|
Variables composed of a collection of elements with the same type |
|
Variables that point to other variables and contain variable locations (in the form of addresses) instead of values |
|
Simple variables with integral type that hold one value from a set of named integer constants |
|
Variables composed of a collection of values that can have different types |
|
Variables composed of several values of different types that occupy the same storage space |
A declarator is the part of a declaration that specifies the name that is to be introduced into the program. It can include modifiers such as * (pointer-to) and any of the Microsoft calling-convention keywords.
Microsoft Specific
In the declarator
__declspec(thread) char *var;
char is the type specifier, __declspec(thread) and * are the modifiers, and var is the identifier's name.
END Microsoft Specific
You use declarators to declare arrays of values, pointers to values, and functions returning values of a specified type. Declarators appear in the array and pointer declarations described later in this section.
Syntax
declarator:
pointer opt direct-declaratordirect-declarator:
identifier( declarator )
direct-declarator [ constant-expression opt ]
direct-declarator ( parameter-type-list )
direct-declarator ( identifier-list opt )
pointer:
*****type-qualifier-list opt*****type-qualifier-list opt pointer
type-qualifier-list:
type-qualifiertype-qualifier-list type-qualifier
备注
See the syntax for declaration in Overview of Declarations or C Language Syntax Summary for the syntax that references a declarator.
When a declarator consists of an unmodified identifier, the item being declared has a base type. If an asterisk (*) appears to the left of an identifier, the type is modified to a pointer type. If the identifier is followed by brackets ([ ]), the type is modified to an array type. If the identifier is followed by parentheses, the type is modified to a function type. For more information about interpreting precedence within declarations, see Interpreting More Complex Declarators.
Each declarator declares at least one identifier. A declarator must include a type specifier to be a complete declaration. The type specifier gives the type of the elements of an array type, the type of object addressed by a pointer type, or the return type of a function.
Array and pointer declarations are discussed in more detail later in this section. The following examples illustrate a few simple forms of declarators:
int list[20]; // Declares an array of 20 int values named list
char *cp; // Declares a pointer to a char value
double func( void ); // Declares a function named func, with no
// arguments, that returns a double value
int *aptr[10] // Declares an array of 10 pointers
Microsoft Specific
The Microsoft C compiler does not limit the number of declarators that can modify an arithmetic, structure, or union type. The number is limited only by available memory.
END Microsoft Specific