mallochistory(1) BSD General Commands Manual mallochistory(1)

NAME
     mmaalllloocchhiissttoorryy - Show the malloc allocations that the process has per-
     formed

SYNOPSIS
     mmaalllloocchhiissttoorryy pid address
     mmaalllloocchhiissttoorryy pid -aallllbbyyssiizzee
     mmaalllloocchhiissttoorryy pid -aallllbbyyccoouunntt

DESCRIPTION
     mmaalllloocchhiissttoorryy inspects a given process and lists the malloc allocations
     performed by it.  mallochistory relies on information provided by the
     standard malloc library when debugging options have been turned on.

     By specifying an address, mmaalllloocchhiissttoorryy lists the allocations and deal-
     locations that have manipulated a buffer at that address.  For each allo-
     cation, a stack trace describing who called malloc or free is listed.

     Alternatively, the -allbysize and -allbycount options will list all
     allocations.  Frequent allocations from the same point in the program
     (that is, the same call stack) are grouped together, and output presented
     either from largest allocations to smallest, or most allocations to
     least.

     All modes require the standard malloc library's debugging facility to be
     turned on.  To do this, set the environment variable MallocStackLogging
     to 1 in the shell that will run the program.  To be able to examine allo-
     cations by address, also set the environment variable MallocStackLogging-
     NoCompact to 1.

     mmaalllloocchhiissttoorryy is particularly useful for tracking down memory smashers.
     Run the program to be inspected with MallocStackLogging and MallocStack-
     LoggingNoCompact defined.  Also set the environment variable MallocScrib-
     ble; this causes the malloc library to overwrite freed memory with a
     well-known value (0x55), and occasionally checks freed buffers to make
     sure the memory has not been overwritten since it was cleared.  When mal-
     loc detects the memory has been written, it will print out a warning that
     the buffer was modified after being freed.  You can then use mallochis-
     tory to find who allocated and freed memory at that address, and thus
     deduce what parts of the code might still have a pointer to the freed
     structure.

SEE ALSO
     malloc(3), heap(1), leaks(1), vmmap(1)

     The developer tools for the system also include a graphical application,
     /Developer/Applications/Instruments.app, that provides instruments that
     give information similar to that provided by mmaalllloocchhiissttoorryy.. The Objec-
     tAlloc instrument graphically displays dynamic, real-time information
     about the object and memory use in an application, including backtraces
     of where the allocations occured.

BSD                             March 15, 2007                             BSD