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[Qemu-devel] [PATCH 1/5] trace: allow trace events with string arguments
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 1/5] trace: allow trace events with string arguments |
Date: |
Wed, 21 Sep 2011 11:36:33 +0100 |
String arguments are useful for producing human-readable traces without
post-processing (e.g. stderr backend). Although the simple backend
cannot handles strings all others can. Strings should be allowed and
the simple backend can be extended to support them.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
docs/tracing.txt | 8 +++-----
1 files changed, 3 insertions(+), 5 deletions(-)
diff --git a/docs/tracing.txt b/docs/tracing.txt
index d0171aa..2c33a62 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -70,11 +70,6 @@ Trace events should use types as follows:
cannot include all user-defined struct declarations and it is therefore
necessary to use void * for pointers to structs.
- Pointers (including char *) cannot be dereferenced easily (or at all) in
- some trace backends. If pointers are used, ensure they are meaningful by
- themselves and do not assume the data they point to will be traced. Do
- not pass in string arguments.
-
* For everything else, use primitive scalar types (char, int, long) with the
appropriate signedness.
@@ -182,6 +177,9 @@ source tree. It may not be as powerful as
platform-specific or third-party
trace backends but it is portable. This is the recommended trace backend
unless you have specific needs for more advanced backends.
+The "simple" backend currently does not capture string arguments, it simply
+records the char* pointer value instead of the string that is pointed to.
+
==== Monitor commands ====
* info trace
--
1.7.5.4
- [Qemu-devel] [PULL 0/5] Tracing patches, Stefan Hajnoczi, 2011/09/21
- [Qemu-devel] [PATCH 1/5] trace: allow trace events with string arguments,
Stefan Hajnoczi <=
- [Qemu-devel] [PATCH 2/5] MAINTAINERS: add tracing subsystem, Stefan Hajnoczi, 2011/09/21
- [Qemu-devel] [PATCH 3/5] trace: portable simple trace backend using glib, Stefan Hajnoczi, 2011/09/21
- [Qemu-devel] [PATCH 4/5] trace: use binary file open mode in simpletrace, Stefan Hajnoczi, 2011/09/21
- [Qemu-devel] [PATCH 5/5] trace: Update docs to use example events that exist, Stefan Hajnoczi, 2011/09/21
- Re: [Qemu-devel] [PULL 0/5] Tracing patches, Anthony Liguori, 2011/09/22