1memory(n) Tcl Built-In Commands memory(n)
2______________________________________________________________________________
6
8 memory - Control Tcl memory debugging capabilities
9
11 memory option ?arg arg ...?
12______________________________________________________________________________
13
15 The memory command gives the Tcl developer control of Tcl's memory
16 debugging capabilities. The memory command has several suboptions,
17 which are described below. It is only available when Tcl has been com‐
18 piled with memory debugging enabled (when TCL_MEM_DEBUG is defined at
19 compile time), and after Tcl_InitMemory has been called.
20 memory active file
22 Write a list of all currently allocated memory to the specified
23 file.
24 memory break_on_malloc count
26 After the count allocations have been performed, ckalloc outputs
27 a message to this effect and that it is now attempting to enter
28 the C debugger. Tcl will then issue a SIGINT signal against
29 itself. If you are running Tcl under a C debugger, it should
30 then enter the debugger command mode.
31 memory info
33 Returns a report containing the total allocations and frees
34 since Tcl began, the current packets allocated (the current num‐
35 ber of calls to ckalloc not met by a corresponding call to
36 ckfree), the current bytes allocated, and the maximum number of
37 packets and bytes allocated.
38 memory init [on|off]
40 Turn on or off the pre-initialization of all allocated memory
41 with bogus bytes. Useful for detecting the use of uninitialized
42 values.
43 memory objs file
45 Causes a list of all allocated Tcl_Obj values to be written to
46 the specified file immediately, together with where they were
47 allocated. Useful for checking for leaks of values.
48 memory onexit file
50 Causes a list of all allocated memory to be written to the spec‐
51 ified file during the finalization of Tcl's memory subsystem.
52 Useful for checking that memory is properly cleaned up during
53 process exit.
54 memory tag string
56 Each packet of memory allocated by ckalloc can have associated
57 with it a string-valued tag. In the lists of allocated memory
58 generated by memory active and memory onexit, the tag for each
59 packet is printed along with other information about the packet.
60 The memory tag command sets the tag value for subsequent calls
61 to ckalloc to be string.
62 memory trace [on|off]
64 Turns memory tracing on or off. When memory tracing is on,
65 every call to ckalloc causes a line of trace information to be
66 written to stderr, consisting of the word ckalloc, followed by
67 the address returned, the amount of memory allocated, and the C
68 filename and line number of the code performing the allocation.
69 For example:
70 ckalloc 40e478 98 tclProc.c 1406
72 Calls to ckfree are traced in the same manner.
74 memory trace_on_at_malloc count
76 Enable memory tracing after count ckallocs have been performed.
77 For example, if you enter memory trace_on_at_malloc 100, after
78 the 100th call to ckalloc, memory trace information will begin
79 being displayed for all allocations and frees. Since there can
80 be a lot of memory activity before a problem occurs, judicious
81 use of this option can reduce the slowdown caused by tracing
82 (and the amount of trace information produced), if you can iden‐
83 tify a number of allocations that occur before the problem sets
84 in. The current number of memory allocations that have occurred
85 since Tcl started is printed on a guard zone failure.
86 memory validate [on|off]
88 Turns memory validation on or off. When memory validation is
89 enabled, on every call to ckalloc or ckfree, the guard zones are
90 checked for every piece of memory currently in existence that
91 was allocated by ckalloc. This has a large performance impact
92 and should only be used when overwrite problems are strongly
93 suspected. The advantage of enabling memory validation is that
94 a guard zone overwrite can be detected on the first call to
95 ckalloc or ckfree after the overwrite occurred, rather than when
96 the specific memory with the overwritten guard zone(s) is freed,
97 which may occur long after the overwrite occurred.
98
100 ckalloc, ckfree, Tcl_ValidateAllMemory, Tcl_DumpActiveMemory,
101 TCL_MEM_DEBUG
102
104 memory, debug
105Tcl 8.1 memory(n)