Provided by: tcl8.5-doc_8.5.19-4_all 
NAME
memory - Control Tcl memory debugging capabilities
SYNOPSIS
memory option ?arg arg ...? ________________________________________________________________________________________________________________
DESCRIPTION
The memory command gives the Tcl developer control of Tcl's memory debugging capabilities. The memory
command has several suboptions, which are described below. It is only available when Tcl has been
compiled with memory debugging enabled (when TCL_MEM_DEBUG is defined at compile time), and after
Tcl_InitMemory has been called.
memory active file
Write a list of all currently allocated memory to the specified file.
memory break_on_malloc count
After the count allocations have been performed, ckalloc outputs a message to this effect and that
it is now attempting to enter the C debugger. Tcl will then issue a SIGINT signal against itself.
If you are running Tcl under a C debugger, it should then enter the debugger command mode.
memory info
Returns a report containing the total allocations and frees since Tcl began, the current packets
allocated (the current number of calls to ckalloc not met by a corresponding call to ckfree), the
current bytes allocated, and the maximum number of packets and bytes allocated.
memory init [on|off]
Turn on or off the pre-initialization of all allocated memory with bogus bytes. Useful for
detecting the use of uninitialized values.
memory objs file
Causes a list of all allocated Tcl_Obj values to be written to the specified file immediately,
together with where they were allocated. Useful for checking for leaks of values.
memory onexit file
Causes a list of all allocated memory to be written to the specified file during the finalization
of Tcl's memory subsystem. Useful for checking that memory is properly cleaned up during process
exit.
memory tag string
Each packet of memory allocated by ckalloc can have associated with it a string-valued tag. In
the lists of allocated memory generated by memory active and memory onexit, the tag for each
packet is printed along with other information about the packet. The memory tag command sets the
tag value for subsequent calls to ckalloc to be string.
memory trace [on|off]
Turns memory tracing on or off. When memory tracing is on, every call to ckalloc causes a line of
trace information to be written to stderr, consisting of the word ckalloc, followed by the address
returned, the amount of memory allocated, and the C filename and line number of the code
performing the allocation. For example:
ckalloc 40e478 98 tclProc.c 1406
Calls to ckfree are traced in the same manner.
memory trace_on_at_malloc count
Enable memory tracing after count ckallocs have been performed. For example, if you enter memory
trace_on_at_malloc 100, after the 100th call to ckalloc, memory trace information will begin being
displayed for all allocations and frees. Since there can be a lot of memory activity before a
problem occurs, judicious use of this option can reduce the slowdown caused by tracing (and the
amount of trace information produced), if you can identify a number of allocations that occur
before the problem sets in. The current number of memory allocations that have occurred since Tcl
started is printed on a guard zone failure.
memory validate [on|off]
Turns memory validation on or off. When memory validation is enabled, on every call to ckalloc or
ckfree, the guard zones are checked for every piece of memory currently in existence that was
allocated by ckalloc. This has a large performance impact and should only be used when overwrite
problems are strongly suspected. The advantage of enabling memory validation is that a guard zone
overwrite can be detected on the first call to ckalloc or ckfree after the overwrite occurred,
rather than when the specific memory with the overwritten guard zone(s) is freed, which may occur
long after the overwrite occurred.
SEE ALSO
ckalloc, ckfree, Tcl_ValidateAllMemory, Tcl_DumpActiveMemory, TCL_MEM_DEBUG
KEYWORDS
memory, debug