[Info-vax] yet another sys$qiow question

[JF Mezei]

On 15-08-22 10:20, Stephen Hoffman wrote:

> Expunge all of the str not-l, not-r variants from current C code being 
> reworked, and from new C code.

I knew mentioning strlen would get your blood pressure to rise :-)

We know that after a call to an extarnal routine, the compiler will
fetch value of variable from memory at least the first time after the call.

My question pertains to C run-time routine which appears to be an
external routine, but which is converted by the compiler into local
code, at which point the compiler will know that a variable has not been
modified and thus not trigger a fetch from memory the next time the
variable is accessed.

Ideally, there should be a way to not penalize a variable for its whole
lifetime (by declaring it "volatile") and only cause the volatile
attribute to be active in certain parts of the code.

someting like

#pragma volatile myvariable
	code that needs actual references to memory
#pragma novolatile myvariable

outside of the #pragma directives, the compiler would be free to
optimize "myvariable"