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.TH STACK 1
.SH NAME
stack, stackv \- examine call stack
.SH SYNOPSIS
.B "bind '#p' /prog"
.br
.B stack
[
.B -v
]
[
.B -p
.I dispath
.I sblpath
]...
.I pid
.br
.B stackv
[
.B -Tlm
] [
.B -r
.I maxdepth
] [
.I pid\fR[\f5.\fIsym\fR] ...] ...
.SH DESCRIPTION
.I Stack
writes to the standard output a stack trace for process
.IR pid ,
by
decoding the stack traceback data contained in the file
.BI /prog/ pid /stack .
The
.B -v
option causes
.I stack
to print values of arguments and variables.
The output is most useful when the Limbo program
was compiled with the
.B -g
option to produce a
.B .sbl
symbol file.
.PP
.I Stack
has a built-in list of associations between
.B dis
directories and their associated source directories
(e.g. it can automatically map from
.B /dis/ls.dis
to
.BR /appl/cmd/ls.sbl ).
Giving the
.B -p
option adds a new association to the head of this list:
if a module path prefix matches
.IR dispath ,
.I stack
will search for a symbol file in
.IR sblpath .
If the environment variable
.B $sblpath
is set, pairs of items from it are added to the
association list, as given as
.B -p
options.
The
.B -p
options take precedence over
.BR $sblpath .
.PP
.I 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
.BR (qv) .
Each argument gives a starting point
for the traversal, rooted by a process id,
.IR 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,
.B 123.init.ctxt.display
might specify the
.B display
field inside the
.B ctxt
adt inside the
.B init
function inside the process
.BR 123 .
.I Stackv
understands the following options:
.TP 10
.B -l
Show source line information with each item.
.TP
.B -m
Show module variables accessible from each stack frame.
.TP
.B -T
Do not show the Limbo types of value encountered.
.TP
.BI -r \ maxdepth
Restrict the maximum traversal depth to
.I maxdepth
levels.
.SH EXAMPLE
Run
.I stack
on process with ID 1:
.IP
.EX
$ 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
.EE
.PP
The process is executing in the
.B Sys
module, a call to
.B sys->read
that originated at line 105 (characters 7 to 38) of the
.B waitfor
function in
.BR shnew.b .
.PP
Once again, with the
.B -v
option to reveal more:
.IP
.EX
$ stack -v 1
unknown fn() Module $Sys PC 742103
waitfor(pid=18) shnew.b:105.7, 38
status=[0] ""
buf=[64] @b419a4
n=-1
who=-1
runpipeline(ctx=nil, pipeline=@b41454) shnew.b:483.2, 14
pid=18
runit(ctx=nil, pipes=nil) shnew.b:552.3, 29
pipeline=@b41454
init(ctxt=nil, argv=nil) shnew.b:83.3, 28
buf=[1024] @b40f04
n=4
arg=@b41634
prompt=[21] "$ "
$
.EE
.SH FILES
.BI /prog/ pid /stack
.br
.BI /prog/ pid /status
.SH SOURCE
.B /appl/cmd/stack.b
.br
.B /appl/cmd/stackv.b
.SH "SEE ALSO"
.IR deb (1),
.IR ps (1),
.IR prog (3),
.IR debug (2)
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