Re: The "black magic" of ioctl

[Florian Weimer <fw@deneb.enyo.de>]

* Frank J. Lhota:

> On 10/24/2010 1:56 PM, Florian Weimer wrote:
>
>> Perhaps it seems to work for you, but this is not portable.  There are
>> popular targets where the varargs calling convention is markedly
>> different from the non-varargs calling convention, such as amd64.
>> It might still work by accident, but all bets are off, really.
>
> The Microsoft documentation seems to say that varargs is _not_
> markedly different; see
>
>     http://msdn.microsoft.com/en-us/library/dd2wa36c%28v=VS.80%29.aspx

There are additional requirements for passing floating-point
arguments.  It's different from Linux that this will only bite you
when you actually pass floating-point arguments which are used in the
callee in a certain way (which should happen with ioctl).