GCC 3.0 Open Issues List feedback

dewar@gnat.com dewar@gnat.com
Sun Apr 8 16:18:00 GMT 2001


<<for the time of a longjmp.  But then, you have to take into account
the extra time of all setjmp()s, and this is far from being
negligible.  As deadlines get stricter, you'd probably be better off
using a lower-overall-overhead exception handling mechanism.  On
machines with lots of call-saved registers, the performance of
setjmp/longjmp EH is awful, and so is its stack usage.
>>

Well remember that in hard real time programs it is worst case
peformance that is at issue, The point about setjmp and longjmp
have more easily predictable behavior, and it is predictability
that is the most important issue. 

Anyway, as I say, in Ada we definitely find it valuable to have
both mechanisms available. There is also the issue that the table
driver methods can require large tables, and memory usage is
often more critical than CPU usage in embedded programs.



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