threads and target-function-calls

[Andrew Cagney]

> Michael Snyder wrote:
> 
>> 
>> Andrew Cagney wrote:
> 
>> >
> 
>> > > Hey folks,
>> > >
>> > > Did you know that (at least on x86 linux), if you have a multi-thread
>> > > program and you execute a target function call, all the threads get to
>> > > run?  Doesn't that seem like a bad thing?  Wouldn't we really rather
>> > > only run the thread that is executing the target function call?
> 
>> >
>> > Ha!  That's just the start.  Doing nested inferior function calls on
>> > alternative threads scrables the dummy frame cache:
>> > http://sources.redhat.com/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gdb&pr=468
> 
>> 
>> But... that's just sick.   ;-(
>> Wait -- you can't do that.  It isn't meaningful to change threads
>> and then continue/whatever.  It assumes gdb has more control over
>> scheduling than it actually has.
> 
> 
> Oh, I think I misunderstood.  You have in mind this:
> 	(gdb) print foo()
> 	[switching thread to xyz]
> 	Breakpoint 2 in foo ()
> 	(gdb) print bar()
> 
> not this:
> 	(gdb) print foo ()
> 	breakpoint 2 in foo()
> 	(gdb) thread xyz
> 	(gdb) print bar()
> 
> right?

Either.  Or even things like:

	(gdb) print foo()
	[new thread xyx]
	Thread xyz hit breakpoint 2 in foo()
	(gdb) print bar()

(there was talk of trying to only allow one thread to run).

Andrew