This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
[Bug translator/2645] Need a syntax to specify optional probes
- From: "fche at redhat dot com" <sourceware-bugzilla at sourceware dot org>
- To: systemtap at sources dot redhat dot com
- Date: 14 May 2006 12:01:06 -0000
- Subject: [Bug translator/2645] Need a syntax to specify optional probes
- References: <20060508205847.2645.joshua.i.stone@intel.com>
- Reply-to: sourceware-bugzilla at sourceware dot org
------- Additional Comments From fche at redhat dot com 2006-05-14 12:01 -------
If I understand the concern correctly, in this scenario,
probe group.f = pp ? { } # in tapset
probe group.* { } # in user script
and for missing "pp", should this succeed or fail? There is an ambiguity.
With the current flavouring of the code, it would fail, since the group.*
match would expand to an empty set of derived_probe's.
With a little bit of extra work, we can let the tapset author make this pass.
Let's provide a new probe point "never", which would be similar to "begin"
and "end" but never actually run its handler. (It doesn't even need to show
up in the translated C code.) Then, if a tapset author wants to make the
alias succeed with a missing pp, even for non-optional users, he can say:
probe group.f = pp ? , never { } # in tapset
--
http://sourceware.org/bugzilla/show_bug.cgi?id=2645
------- You are receiving this mail because: -------
You are the assignee for the bug, or are watching the assignee.