"TCPL/A.04.1_Storage_Class"版本比较

A.4.1 Storage Class

There are two storage classes: automatic and static. Several keywords, together with the context of an object's declaration, specify its storage class. Automatic objects are local to a block (Par.9.3), and are discarded on exit from the block. Declarations within a block create automatic objects if no storage class specification is mentioned, or if the auto specifier is used. Objects declared register are automatic, and are (if possible) stored in fast registers of the machine.

Static objects may be local to a block or external to all blocks, but in either case retain their values across exit from and reentry to functions and blocks. Within a block, including a block that provides the code for a function, static objects are declared with the keyword static. The objects declared outside all blocks, at the same level as function definitions, are always static. They may be made local to a particular translation unit by use of the static keyword; this gives them internal linkage. They become global to an entire program by omitting an explicit storage class, or by using the keyword extern; this gives them external linkage.