🚀 go-pugleaf

In article <4ubogp$e8a@mule1.mindspring.com>
           mroot@atl.mindspring.com "Danette & Murray Root" writes:

>On 7 Aug 1996 22:35:57 -0500, mrbig@freeside.fc.net (Mike Big) wrote
>in comp.lang.c:
>
>=>/* 
>=>I'v found what I think might be a bug in gcc's optimization.  The
>
>That's not a bug, that's the reason for the 'volatile' keyword.

And also sig_atomic_t. What the code actually violates is (ISO 7.7.1.1):

"If the signal occurs other than as the result of calling the abort or
 raise function, the behaviour is undefined if the signal handler calls
 any function in the standard library other than the signal function
 itself (with a first argument corresponding to the signal that caused
 the invocation of the handler) or refers to any object with static
 storage duration other than by assigning a value to a static storage
 duration variable of type volatile sig_atomic_t."

This allows the compiler to optimise the foreground loop without breaking the
standard. As you can see there is very little that you can do in a signal
handler and remain as strictly conforming C. You can perform calculations
using auto variables and notify events/state changes back to the foreground
code through static variables of type volatile sig_atomic_t which the
foreground code has to poll.

-- 
-----------------------------------------
Lawrence Kirby | fred@genesis.demon.co.uk
Wilts, England | 70734.126@compuserve.com
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