Tcl Source Code

Check-in [83d7bff763]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Implement TIp 543.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256: 83d7bff763c02cfc7ab0a386a5169d0d5333e03e0500d05b140baf5f0876a50a
User & Date: dgp 2020-01-21 22:14:55
Context
2020-01-23
09:47
merge-mark check-in: 3541ad71e9 user: jan.nijtmans tags: trunk
2020-01-22
15:43
merge trunk check-in: 0f0012b0b7 user: dgp tags: dgp-refactor
15:29
merge trunk check-in: e8d6895827 user: dgp tags: novem
15:28
merge trunk check-in: d7ec907d9b user: dgp tags: dgp-properbytearray
2020-01-21
22:14
Implement TIp 543. check-in: 83d7bff763 user: dgp tags: trunk
22:00
Implement TIP 543 check-in: 7f045bde78 user: dgp tags: core-8-branch
09:21
Enable test-cases stringObj-15.[5-8]: "nodep" restriction doesn't work in 9.0. check-in: 71408e874a user: jan.nijtmans tags: trunk
2020-01-10
17:40
merge trunk Closed-Leaf check-in: a989de7067 user: dgp tags: tip-543-9
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to doc/TraceVar.3.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
'\"
'\" Copyright (c) 1989-1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH Tcl_TraceVar 3 7.4 Tcl "Tcl Library Procedures"
.so man.macros
.BS
.SH NAME
Tcl_TraceVar, Tcl_TraceVar2, Tcl_UntraceVar, Tcl_UntraceVar2, Tcl_VarTraceInfo, Tcl_VarTraceInfo2 \- monitor accesses to a variable
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR







|







1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
'\"
'\" Copyright (c) 1989-1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH Tcl_TraceVar 3 9.0 Tcl "Tcl Library Procedures"
.so man.macros
.BS
.SH NAME
Tcl_TraceVar, Tcl_TraceVar2, Tcl_UntraceVar, Tcl_UntraceVar2, Tcl_VarTraceInfo, Tcl_VarTraceInfo2 \- monitor accesses to a variable
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
\fBTCL_TRACE_WRITES\fR
Invoke \fIproc\fR whenever an attempt is made to modify the variable.
.TP
\fBTCL_TRACE_UNSETS\fR
Invoke \fIproc\fR whenever the variable is unset.
A variable may be unset either explicitly by an \fBunset\fR command,
or implicitly when a procedure returns (its local variables are
automatically unset) or when the interpreter is deleted (all
variables are automatically unset).
.TP
\fBTCL_TRACE_ARRAY\fR
Invoke \fIproc\fR whenever the array command is invoked.
This gives the trace procedure a chance to update the array before
array names or array get is called.  Note that this is called
before an array set, but that will trigger write traces.







|







91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
\fBTCL_TRACE_WRITES\fR
Invoke \fIproc\fR whenever an attempt is made to modify the variable.
.TP
\fBTCL_TRACE_UNSETS\fR
Invoke \fIproc\fR whenever the variable is unset.
A variable may be unset either explicitly by an \fBunset\fR command,
or implicitly when a procedure returns (its local variables are
automatically unset) or when the interpreter or namespace is deleted (all
variables are automatically unset).
.TP
\fBTCL_TRACE_ARRAY\fR
Invoke \fIproc\fR whenever the array command is invoked.
This gives the trace procedure a chance to update the array before
array names or array get is called.  Note that this is called
before an array set, but that will trigger write traces.
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
procedure call:  the trace procedure will need to pass this flag
back to variable-related procedures like \fBTcl_GetVar\fR if it
attempts to access the variable.
The bit \fBTCL_TRACE_DESTROYED\fR will be set in \fIflags\fR if the trace is
about to be destroyed;  this information may be useful to \fIproc\fR
so that it can clean up its own internal data structures (see
the section \fBTCL_TRACE_DESTROYED\fR below for more details).
Lastly, the bit \fBTCL_INTERP_DESTROYED\fR will be set if the entire
interpreter is being destroyed.
When this bit is set, \fIproc\fR must be especially careful in
the things it does (see the section \fBTCL_INTERP_DESTROYED\fR below).
The trace procedure's return value should normally be NULL;  see
\fBERROR RETURNS\fR below for information on other possibilities.
.PP
\fBTcl_UntraceVar\fR may be used to remove a trace.
If the variable specified by \fIinterp\fR, \fIvarName\fR, and \fIflags\fR
has a trace set with \fIflags\fR, \fIproc\fR, and
\fIclientData\fR, then the corresponding trace is removed.







<
<
<
<







156
157
158
159
160
161
162




163
164
165
166
167
168
169
procedure call:  the trace procedure will need to pass this flag
back to variable-related procedures like \fBTcl_GetVar\fR if it
attempts to access the variable.
The bit \fBTCL_TRACE_DESTROYED\fR will be set in \fIflags\fR if the trace is
about to be destroyed;  this information may be useful to \fIproc\fR
so that it can clean up its own internal data structures (see
the section \fBTCL_TRACE_DESTROYED\fR below for more details).




The trace procedure's return value should normally be NULL;  see
\fBERROR RETURNS\fR below for information on other possibilities.
.PP
\fBTcl_UntraceVar\fR may be used to remove a trace.
If the variable specified by \fIinterp\fR, \fIvarName\fR, and \fIflags\fR
has a trace set with \fIflags\fR, \fIproc\fR, and
\fIclientData\fR, then the corresponding trace is removed.
325
326
327
328
329
330
331










332
333
334
335
336
337
338
value).
.PP
The return value from \fIproc\fR is only used during read and
write tracing.
During unset traces, the return value is ignored and all relevant
trace procedures will always be invoked.
.SH "RESTRICTIONS"










.PP
A trace procedure can be called at any time, even when there
are partially formed results stored in the interpreter.  If
the trace procedure does anything that could damage this result (such
as calling \fBTcl_Eval\fR) then it must use the \fBTcl_SaveInterpState\fR
and related routines to save and restore the original state of
the interpreter before it returns.







>
>
>
>
>
>
>
>
>
>







321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
value).
.PP
The return value from \fIproc\fR is only used during read and
write tracing.
During unset traces, the return value is ignored and all relevant
trace procedures will always be invoked.
.SH "RESTRICTIONS"
.PP
Because operations on variables may take place as part of the deletion
of the interp that contains them, \fIproc\fR must be careful about checking
what the \fIinterp\fR parameter can be used to do.
The routine \fBTcl_InterpDeleted\fR is an important tool for this.
When \fBTcl_InterpDeleted\fR returns 1, \fIproc\fR will not be able
to invoke any scripts in \fIinterp\fR. You may encounter old code using
a deprecated flag value \fBTCL_INTERP_DESTROYED\fR to signal this
condition, but Tcl 9 no longer supports this. Any supported code
must be converted to stop using it.
.PP
A trace procedure can be called at any time, even when there
are partially formed results stored in the interpreter.  If
the trace procedure does anything that could damage this result (such
as calling \fBTcl_Eval\fR) then it must use the \fBTcl_SaveInterpState\fR
and related routines to save and restore the original state of
the interpreter before it returns.
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
In an unset callback to \fIproc\fR, the \fBTCL_TRACE_DESTROYED\fR bit
is set in \fIflags\fR if the trace is being removed as part
of the deletion.
Traces on a variable are always removed whenever the variable
is deleted;  the only time \fBTCL_TRACE_DESTROYED\fR is not set is for
a whole-array trace invoked when only a single element of an
array is unset.
.SH "TCL_INTERP_DESTROYED"
.PP
When an interpreter is destroyed, unset traces are called for
all of its variables.
The \fBTCL_INTERP_DESTROYED\fR bit will be set in the \fIflags\fR
argument passed to the trace procedures.
Trace procedures must be extremely careful in what they do if
the \fBTCL_INTERP_DESTROYED\fR bit is set.
It is not safe for the procedures to invoke any Tcl procedures
on the interpreter, since its state is partially deleted.
All that trace procedures should do under these circumstances is
to clean up and free their own internal data structures.
.SH BUGS
.PP
Tcl does not do any error checking to prevent trace procedures
from misusing the interpreter during traces with \fBTCL_INTERP_DESTROYED\fR
set.
.PP
Array traces are not yet integrated with the Tcl \fBinfo exists\fR command,
nor is there Tcl-level access to array traces.
.SH "SEE ALSO"
trace(n)
.SH KEYWORDS
clientData, trace, variable







<
<
<
<
<
<
<
<
<
<
<
<


<
<
<
<






356
357
358
359
360
361
362












363
364




365
366
367
368
369
370
In an unset callback to \fIproc\fR, the \fBTCL_TRACE_DESTROYED\fR bit
is set in \fIflags\fR if the trace is being removed as part
of the deletion.
Traces on a variable are always removed whenever the variable
is deleted;  the only time \fBTCL_TRACE_DESTROYED\fR is not set is for
a whole-array trace invoked when only a single element of an
array is unset.












.SH BUGS
.PP




Array traces are not yet integrated with the Tcl \fBinfo exists\fR command,
nor is there Tcl-level access to array traces.
.SH "SEE ALSO"
trace(n)
.SH KEYWORDS
clientData, trace, variable

Changes to generic/tcl.h.

870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
#define TCL_NAMESPACE_ONLY	 2
#define TCL_APPEND_VALUE	 4
#define TCL_LIST_ELEMENT	 8
#define TCL_TRACE_READS		 0x10
#define TCL_TRACE_WRITES	 0x20
#define TCL_TRACE_UNSETS	 0x40
#define TCL_TRACE_DESTROYED	 0x80
#define TCL_INTERP_DESTROYED	 0x100
#define TCL_LEAVE_ERR_MSG	 0x200
#define TCL_TRACE_ARRAY		 0x800
#ifndef TCL_REMOVE_OBSOLETE_TRACES
/* Required to support old variable/vdelete/vinfo traces. */
#define TCL_TRACE_OLD_STYLE	 0x1000
#endif
/* Indicate the semantics of the result of a trace. */







|







870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
#define TCL_NAMESPACE_ONLY	 2
#define TCL_APPEND_VALUE	 4
#define TCL_LIST_ELEMENT	 8
#define TCL_TRACE_READS		 0x10
#define TCL_TRACE_WRITES	 0x20
#define TCL_TRACE_UNSETS	 0x40
#define TCL_TRACE_DESTROYED	 0x80

#define TCL_LEAVE_ERR_MSG	 0x200
#define TCL_TRACE_ARRAY		 0x800
#ifndef TCL_REMOVE_OBSOLETE_TRACES
/* Required to support old variable/vdelete/vinfo traces. */
#define TCL_TRACE_OLD_STYLE	 0x1000
#endif
/* Indicate the semantics of the result of a trace. */

Changes to generic/tclTrace.c.

75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
 * TCL_TRACE_ANY_EXEC		- OR'd combination of all EXEC flags.
 * TCL_TRACE_EXEC_IN_PROGRESS   - The callback function on this trace is
 *				  currently executing. Therefore we don't let
 *				  further traces execute.
 * TCL_TRACE_EXEC_DIRECT	- This execution trace is triggered directly
 *				  by the command being traced, not because of
 *				  an internal trace.
 * The flags 'TCL_TRACE_DESTROYED' and 'TCL_INTERP_DESTROYED' may also be used
 * in command execution traces.
 */

#define TCL_TRACE_ENTER_DURING_EXEC	4
#define TCL_TRACE_LEAVE_DURING_EXEC	8
#define TCL_TRACE_ANY_EXEC		15
#define TCL_TRACE_EXEC_IN_PROGRESS	0x10
#define TCL_TRACE_EXEC_DIRECT		0x20







<
|







75
76
77
78
79
80
81

82
83
84
85
86
87
88
89
 * TCL_TRACE_ANY_EXEC		- OR'd combination of all EXEC flags.
 * TCL_TRACE_EXEC_IN_PROGRESS   - The callback function on this trace is
 *				  currently executing. Therefore we don't let
 *				  further traces execute.
 * TCL_TRACE_EXEC_DIRECT	- This execution trace is triggered directly
 *				  by the command being traced, not because of
 *				  an internal trace.

 * The flag 'TCL_TRACE_DESTROYED' may also be used in command execution traces.
 */

#define TCL_TRACE_ENTER_DURING_EXEC	4
#define TCL_TRACE_LEAVE_DURING_EXEC	8
#define TCL_TRACE_ANY_EXEC		15
#define TCL_TRACE_EXEC_IN_PROGRESS	0x10
#define TCL_TRACE_EXEC_DIRECT		0x20
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
		    copiedName = 1;
		}
		break;
	    }
	}
    }

    /*
     * Ignore any caller-provided TCL_INTERP_DESTROYED flag.  Only we can
     * set it correctly.
     */

    flags &= ~TCL_INTERP_DESTROYED;

    /*
     * Invoke traces on the array containing the variable, if relevant.
     */

    result = NULL;
    active.nextPtr = iPtr->activeVarTracePtr;
    iPtr->activeVarTracePtr = &active;







<
<
<
<
<
<
<







2639
2640
2641
2642
2643
2644
2645







2646
2647
2648
2649
2650
2651
2652
		    copiedName = 1;
		}
		break;
	    }
	}
    }








    /*
     * Invoke traces on the array containing the variable, if relevant.
     */

    result = NULL;
    active.nextPtr = iPtr->activeVarTracePtr;
    iPtr->activeVarTracePtr = &active;
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
	    if (!(tracePtr->flags & flags)) {
		continue;
	    }
	    Tcl_Preserve(tracePtr);
	    if (state == NULL) {
		state = Tcl_SaveInterpState((Tcl_Interp *) iPtr, code);
	    }
	    if (Tcl_InterpDeleted((Tcl_Interp *) iPtr)) {
		flags |= TCL_INTERP_DESTROYED;
	    }
	    result = tracePtr->traceProc(tracePtr->clientData,
		    (Tcl_Interp *) iPtr, part1, part2, flags);
	    if (result != NULL) {
		if (flags & TCL_TRACE_UNSETS) {
		    /*
		     * Ignore errors in unset traces.
		     */







<
<
<







2661
2662
2663
2664
2665
2666
2667



2668
2669
2670
2671
2672
2673
2674
	    if (!(tracePtr->flags & flags)) {
		continue;
	    }
	    Tcl_Preserve(tracePtr);
	    if (state == NULL) {
		state = Tcl_SaveInterpState((Tcl_Interp *) iPtr, code);
	    }



	    result = tracePtr->traceProc(tracePtr->clientData,
		    (Tcl_Interp *) iPtr, part1, part2, flags);
	    if (result != NULL) {
		if (flags & TCL_TRACE_UNSETS) {
		    /*
		     * Ignore errors in unset traces.
		     */
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
	    if (!(tracePtr->flags & flags)) {
		continue;
	    }
	    Tcl_Preserve(tracePtr);
	    if (state == NULL) {
		state = Tcl_SaveInterpState((Tcl_Interp *) iPtr, code);
	    }
	    if (Tcl_InterpDeleted((Tcl_Interp *) iPtr)) {
		flags |= TCL_INTERP_DESTROYED;
	    }
	    result = tracePtr->traceProc(tracePtr->clientData,
		    (Tcl_Interp *) iPtr, part1, part2, flags);
	    if (result != NULL) {
		if (flags & TCL_TRACE_UNSETS) {
		    /*
		     * Ignore errors in unset traces.
		     */







<
<
<







2702
2703
2704
2705
2706
2707
2708



2709
2710
2711
2712
2713
2714
2715
	    if (!(tracePtr->flags & flags)) {
		continue;
	    }
	    Tcl_Preserve(tracePtr);
	    if (state == NULL) {
		state = Tcl_SaveInterpState((Tcl_Interp *) iPtr, code);
	    }



	    result = tracePtr->traceProc(tracePtr->clientData,
		    (Tcl_Interp *) iPtr, part1, part2, flags);
	    if (result != NULL) {
		if (flags & TCL_TRACE_UNSETS) {
		    /*
		     * Ignore errors in unset traces.
		     */