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Re: [6.2] PROBLEMS file
- From: mec dot gnu at mindspring dot com (Michael Elizabeth Chastain)
- To: brobecker at gnat dot com, kettenis at chello dot nl
- Cc: cagney at gnu dot org, eliz at gnu dot org, gdb at sources dot redhat dot com,hjl at lucon dot org
- Date: Thu, 22 Jul 2004 20:46:54 -0400 (EDT)
- Subject: Re: [6.2] PROBLEMS file
joel> FWIW: As a user, I don't mind when the unwinder goes too far and
joel> displays too many frames. The info we're looking for is there, and
joel> that's what really counts for me. Not pretty, but good enough.
joel> So I wouldn't mind closing that particular PR, especially since
joel> there doesn't seem to be any accurate way of detecting the top
joel> of the call stack.
There are really two separate problems here. gdb/1505 is all about
top-of-stack detection. How about we document the limitation and
live with it.
The existing text is:
Most programs have a standard user entry point---a place where system
libraries and startup code transition into user code. For C this is
@code{main}. When @value{GDBN} finds the entry function in a
backtrace it will terminate the backtrace, to avoid tracing into highly
system-specific (and generally uninteresting) code.
How about adding something like this:
@value{GDBN} is not perfect at detecting the top of the call stack.
For instance, if your program creates multiple threads, then the
stack of an individual thread may not start with @code{main} at all.
So you may see strange frames at the top of the stack; it is safe to
ignore these.
If we document it, I am okay with closing the PR.
(And while I was reading the doco I noticed "set backtrace limit" is
already implemented, which is exactly what I want for callfuncs.exp!)
The other problem is strange frames in the middle that cause the
trace to go bad before it gets to any interesting user code.
That's a different, and much worse, problem, but it's not PR gdb/1505.
See PR gdb/1255 and PR gdb/1253. Those two particular PR's have been
fixed.
Michael C