Re: "standard" C calling convention?

"Christian Bau" <christian.bau@cbau.freeserve.co.uk> wrote in message
news:03-02-091@comp.compilers...
> > Well, many OS have somewhat of a standard, and C programs on that OS
> > may or may not use it. C requires the ability to call with a variable
> > number of arguments, which restricts somewhat the allowable calling
> > conventions
(snip)


> C requires that ability only for calls to functions that are declared to
> have a variable number of arguments. On a PowerPC, calling f (3) will
> generate very different code if f is declared to take one argument or
> declared to take a variable number of arguments.


Probably you are right. I don't believe this was true in K&R
(pre-ANSI) C, and for backward compatibility C compilers wouldn't
require it. For implementations on machines that existed before ANSI
C, the calling convention would have been established, and there is
resistance to change. (Backwards compatibility again.) For newer
machines, where a calling convention didn't exist yet and K&R
compatibility isn't required, that may be reasonable.


-- glen

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