.TH STACK 1
.SH NAME
stack \- examine call stack
.SH SYNOPSIS
.B "bind '#p' /prog"
.br
.B stack
[
.B -v
]
[
.B -p
.I dispath
.I sblpath
]...
.I pid
.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 .
.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
.SH "SEE ALSO"
.IR deb (1),
.IR ps (1),
.IR prog (3),
.IR debug (2)