register storage class
| register storage class | Register storage class specifier |
storage-class-specifier := register
|
The register storage class is like auto: it can be used for local objects and function parameters, and using it means that the declared object has automatic lifetime. It also provides a hint to the compiler that the object will be used frequently, so the compiler can optimize access, perhaps by storing the object in a machine register.
Many modern compilers routinely ignore register because the compilers are better than humans at allocating registers.
Example
int foo(register int parm)
{
register int sqr = parm * parm;
return sqr;
}
See Also
auto, type, Chapter 2
