Shifting question

[Doug Gwyn]

In article <11592 at steinmetz.ge.com> davidsen at crdos1.UUCP (bill davidsen) writes:
>| >	...If the value of the right operand is negative or is greater than or
>| >	equal to the width in bits of the promoted left operand, the behavior
>| >	is undefined.
>  So you have to build in an explicit check in every program, comparing
>the shift with the size of the item.

No; the vast majority of shifts in C applications do not require
the check.  However, if the language guaranteed the behavior you
want it to, then on many architectures a far larger percentage of
shifts would have to perform the check (in the compiler-generated
code).  This is one of the many cases where C is deliberately
permissive in order to allow a better fit to the hardware.  It is
of course not what an "ideal" programming language would do, where
"ideal" includes the notion of suitable hardware.