STACK(1)STACK(1)NAME
stack, stackv - examine call stackSYNOPSIS
bind '#p' /prog
stack [ -v ] [ -p dispath sblpath ]... pid
stackv [ -Tlm ] [ -r maxdepth ] [ pid[.sym] ...] ...
DESCRIPTION
Stack writes to the standard output a stack trace for process pid, by
decoding the stack traceback data contained in the file
/prog/pid/stack. The -v option causes stack to print values of argu‐
ments and variables. The output is most useful when the Limbo program
was compiled with the -g option to produce a .sbl symbol file.
Stack has a built-in list of associations between dis directories and
their associated source directories (e.g. it can automatically map from
/dis/ls.dis to /appl/cmd/ls.sbl). Giving the -p option adds a new
association to the head of this list: if a module path prefix matches
dispath, stack will search for a symbol file in sblpath. If the envi‐
ronment variable $sblpath is set, pairs of items from it are added to
the association list, as given as -p options. The -p options take
precedence over $sblpath.
Stackv recursively traverses the symbols it finds, printing values as
it goes. Repeated identical structure is not shown - only the pointer
value is printed, followed by (qv). Each argument gives a starting
point for the traversal, rooted by a process id, pid. If an unadorned
process id is given, all values in all stack frames in the process will
be printed; adding names specifies the starting point. For instance,
123.init.ctxt.display might specify the display field inside the ctxt
adt inside the init function inside the process 123. Stackv under‐
stands the following options:
-l Show source line information with each item.
-m Show module variables accessible from each stack frame.
-T Do not show the Limbo types of value encountered.
-r maxdepth
Restrict the maximum traversal depth to maxdepth levels.
EXAMPLE
Run stack on process with ID 1:
$ stack 1
unknown fn() Module $Sys PC 742103
waitfor() shnew.b:105.7, 38
runpipeline() shnew.b:483.2, 14
runit() shnew.b:552.3, 29
init() shnew.b:83.3, 28
The process is executing in the Sys module, a call to sys->read that
originated at line 105 (characters 7 to 38) of the waitfor function in
shnew.b.
Once again, with the -v option to reveal more:
$ stack-v 1
unknown fn() Module $Sys PC 742103
waitfor(pid=18) shnew.b:105.7, 38
status=[0] ""
buf=[64] @b419a4
n=-1
who=-1
runpipeline(ctx=nil, pipeline=@b41454) shnew.b:483.2, 14
pid=18
runit(ctx=nil, pipes=nil) shnew.b:552.3, 29
pipeline=@b41454
init(ctxt=nil, argv=nil) shnew.b:83.3, 28
buf=[1024] @b40f04
n=4
arg=@b41634
prompt=[21] "$ "
$
FILES
/prog/pid/stack
/prog/pid/status
SOURCE
/appl/cmd/stack.b
/appl/cmd/stackv.b
SEE ALSOdeb(1), ps(1), prog(3), debug(2)STACK(1)
