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Postings from January 2003
Dave Mitchell wrote:
> On Mon, Jan 20, 2003 at 06:51:02PM +0000, Dave Mitchell wrote:
> > I think I now know what's happening (at least mostly).
> >
> > perl5db.pl uses the magic typeglob PL_DBline (aka DB::dbline) to
> > set breakpoints.
> >
> > The magic for this typeglob calls Perl_magic_setdbline, which
> > sets op_private of the COP associated with the breakpoint to 1 or 0
> > as appropriate.
> >
> > Im not sure where the value 2 comes into play, though.
>
> Further thoughts - I'm guessing that the 0x2 was just HINT_STRICT_REFS
> leaking from PL_hints and that the debugging only uses 1 bit of
> op_private.
That's correct. 0x2 is the compile-time value of the cop->op_private.
setdbline() overwrites it with 0x1.
> If this is the case, we could steal the unused 0x10 bit of HINTS and
> use that to do the signalling, by appropriately modifying pp_dbstate() and
> Perl_magic_setdbline().
>
> How does that sound as a plan?
I approve. _Untested_ first shot :
Index: pp_ctl.c
===================================================================
--- pp_ctl.c (revision 591)
+++ pp_ctl.c (working copy)
@@ -1582,7 +1582,8 @@
PL_stack_sp = PL_stack_base + cxstack[cxstack_ix].blk_oldsp;
FREETMPS;
- if (PL_op->op_private || SvIV(PL_DBsingle) || SvIV(PL_DBsignal) || SvIV(PL_DBtrace))
+ if (PL_op->op_private & OPpDBLINE
+ || SvIV(PL_DBsingle) || SvIV(PL_DBsignal) || SvIV(PL_DBtrace))
{
dSP;
register CV *cv;
Index: perl.h
===================================================================
--- perl.h (revision 591)
+++ perl.h (working copy)
@@ -3215,6 +3215,7 @@
#define HINT_STRICT_REFS 0x00000002 /* strict pragma */
#define HINT_LOCALE 0x00000004 /* locale pragma */
#define HINT_BYTES 0x00000008 /* bytes pragma */
+/* reserved by the debugger, see OPpDBLINE */
/* #define HINT_notused10 0x00000010 */
/* Note: 20,40,80 used for NATIVE_HINTS */
/* currently defined by vms/vmsish.h */
Index: mg.c
===================================================================
--- mg.c (revision 607)
+++ mg.c (working copy)
@@ -1459,7 +1459,10 @@
svp = av_fetch(GvAV(gv),
atoi(MgPV(mg,n_a)), FALSE);
if (svp && SvIOKp(*svp) && (o = INT2PTR(OP*,SvIVX(*svp))))
- o->op_private = (U8)i;
+ if (i)
+ o->op_private |= OPpDBLINE;
+ else
+ o->op_private &= ~OPpDBLINE;
return 0;
}
Index: op.h
===================================================================
--- op.h (revision 591)
+++ op.h (working copy)
@@ -202,6 +202,9 @@
#define OPpHUSH_VMSISH 64 /* hush DCL exit msg vmsish mode*/
#define OPpEXIT_VMSISH 128 /* exit(0) vs. exit(1) vmsish mode*/
+/* Private for OP_DBSTATE */
+#define OPpDBLINE 0x10 /* matches HINT_notused10 */
+
struct op {
BASEOP
};