Provided by: tcl9.0-doc_9.0.1+dfsg-1_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, Tcl_Alloc 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 Tcl_Alloc not met by a corresponding call to Tcl_Free),
the current bytes allocated, and the maximum number of packets and bytes allocated.
memory init [on|off]
Turn on or off the preinitialization 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 Tcl_Alloc 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 Tcl_Alloc to be string.
memory trace [on|off]
Turns memory tracing on or off. When memory tracing is on, every call to Tcl_Alloc causes a line
of trace information to be written to stderr, consisting of the word Tcl_Alloc, 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:
Tcl_Alloc 40e478 98 tclProc.c 1406
Calls to Tcl_Free are traced in the same manner.
memory trace_on_at_malloc count
Enable memory tracing after count Tcl_Allocs have been performed. For example, if you enter
memory trace_on_at_malloc 100, after the 100th call to Tcl_Alloc, 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 Tcl_Alloc
or Tcl_Free, the guard zones are checked for every piece of memory currently in existence that was
allocated by Tcl_Alloc. 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 Tcl_Alloc or Tcl_Free 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
Tcl_Alloc, Tcl_Free, Tcl_ValidateAllMemory, Tcl_DumpActiveMemory, TCL_MEM_DEBUG
KEYWORDS
memory, debug