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Frank Ch. Eigler wrote:
Hi -
[...]
Being that for user-level probes, every pointer dereference is in
user space, I believe it is certain that this difficulty will arise
elsewhere.
Perhaps I was being unclear. The "difficulty" I was referring to was
the ambiguity in whether an ordinary or special dereference operation
is required for any given $var->field expression.
Understood. The "difficulty" I was referring to was the necessity to
write embedded
C auxiliary functions to access user-space pointer arguments.
[...]It is this ambiguity that could be resolved by the user via a
language extension, and it is this ambiguity that does not exist for
variables that show up in user-level probes.
Agreed. A language extension would require the script writer to know
where the
pointer was looking, thus eliminating any ambiguity or difficulty. Do we
agree that
this would be a useful mechanism for user-level probes and the syscall
tapset, among
possible others?
- FChE
--
Kevin Stafford
DES 2 | MS 2M3
Beaverton - OR
Linux Technology Center
IBM Systems & Technology
Phone: 1-503-578-3039
Email: kevinrs@us.ibm.com
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