On 06/12/2018 10:50 PM, Emilio G. Cota wrote:
On Tue, Jun 12, 2018 at 23:15:49 -0400, Yaowei Bai wrote:
Signed-off-by: Yaowei Bai <baiyao...@cmss.chinamobile.com>
---
docs/devel/tracing.txt | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.txt
index 07abbb3..6ab32cc 100644
--- a/docs/devel/tracing.txt
+++ b/docs/devel/tracing.txt
@@ -18,7 +18,7 @@ for debugging, profiling, and observing execution.
3. Run the virtual machine to produce a trace file:
- qemu -trace events=/tmp/events ... # your normal QEMU invocation
+ qemu --trace events=/tmp/events ... # your normal QEMU invocation
The second dash is not missing; both '-args' and '--args' work.
'-args' seems to be favoured though; see `qemu -h' or `qemu --h' :-)
Actually, we're trying to fix that:
https://wiki.qemu.org/BiteSizedTasks#Consistent_option_usage_in_documentation
The one-vs-two dash usage is only supported in qemu, not in qemu-nbd or
qemu-img (that is, qemu acts as if it uses getopt_long_only(), while the
others use getopt_long() - except that we hand-rolled the parser in
qemu, meaning you might find quirks where it sometimes doesn't even
match getopt_long_only()).
At any rate, since --trace is an option that is supported across
multiple binaries, we SHOULD favor the double-dash spelling in our
documentation, so that you can consistently reuse the same --trace
invocation without worrying whether the binary parses its arguments with
getopt_long() (where double is required) or like getopt_long_only()
(where the double is optional but supported).
So I'm in favor of this patch, although it may need more of a commit
message summarizing the justification I've just pointed you to.
Reviewed-by: Eric Blake <ebl...@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
