Re: [RFC] Endianness and signals

From: Cary Coutant <>
Date: 2003-10-22 07:57:50
> The fourth case is that the application has signal handlers that
> expect to get called in the "opposite" byte-order and those are the
> ones that would break if we changed the current behavior.

Do you know of any such applications?

How likely is it that someone would code an application in such a way 
that they guarantee that a certain signal will occur only when 
executing in big-endian mode? (And, conversely, that other signals will 
occur only when executing in little-endian mode?)

If I were writing such an application, and I wanted to figure out what 
to expect when a signal handler is called, my first thought* would be 
to expect it to get called in a standard (i.e., little-endian) mode, no 
matter what. I might then test it and discover that I was wrong. At 
that point, I'd hardly consider that a definitive feature of Linux on 
IA-64; I'd be much more likely to consider it a bug, and bring it to 
someone's attention.

Of course, I realize that most people don't go through that thought 
process -- they assume that the way it works today is the way it will 
always work. I just have a hard time working up any sympathy for those 

By the way, when you arm the signal handler, do you copy the function 
pointer or the function descriptor? Will the user-space code that makes 
the call to the signal handler work if you're in big-endian mode?


* Actually, my first thought would be to see if it's documented 
somewhere. But this is Linux. :-)

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Received on Tue Oct 21 18:01:58 2003

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