CC78K0S Datasheet, PDF (41/520 Pages) NEC – C Compiler Ver.1.30 or Later Language

CHAPTER 2 CONSTRUCTS OF C LANGUAGE
2.3.3 Name space for identifiers
All identifiers are classified into the following “name spaces”.
• Label name ........................................................ Distinguished by a label declaration.
• Tag name of structure, union, or enumeration... Distinguished by the keyword struct, union or enum
• Member name of structure or union................... Distinguished by the dot (.) operator or arrow (->) operator.
• Ordinary identifiers (other than above) .............. Declared as ordinary declarators or enumeration type constants.
2.3.4 Storage duration of objects
Each object has a storage duration that determines its lifetime (how long it can remain in memory). This storage
duration is divided into the following two categories: static storage duration and automatic storage duration
(1) Static storage duration
Before executing an object program that has a static duration, an area is reserved for objects and values to be
stored are initialized once. The objects exist throughout the execution of the entire program and retain the
values last stored.
Objects that have a static storage duration are as follows.
• Objects that have external linkage
• Objects that have internal linkage
• Objects declared by storage class specifier static
(2) Automatic storage duration
For objects that have automatic storage duration, an area is reserved when they enter a block to be declared.
If initialization is specified, the objects are initialized as they enter from the beginning of the block. In this case, if
any object enters the block by jumping to a label within the block, the object will not be initialized.
For objects that have automatic storage duration, the reserved area will not be guaranteed after the execution of
the declared block.
Objects that have automatic storage duration are as follows.
• Objects that have no linkage
• Objects declared inside a block without storage class specifier static
2.3.5 Data types
Data types determine the meaning of a value to be stored in each object and are divided into the following three
categories.
• Object type................................................... Type that indicates an object with size information
• Function type ............................................... Type that indicates a function
• Incomplete type ........................................... Type that indicates an object without size information
The type categories are shown below.
User’s Manual U14872EJ1V0UM
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