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stringdups(1)             BSD General Commands Manual            stringdups(1)

     stringdups -- Identify duplicate strings or other objects in malloc blocks of a target process

     stringdups [-minimumCount count] [-stringsOnly] [-nostacks] [-callTrees] [-invertCallTrees] pid |

     stringdups examines the content of malloc blocks in the specified target process.  For all blocks which
     have the same content, it shows a line with the number of such blocks, their total allocated size (the
     total size in the malloc heap, not just the specific size of their content), and the average allocated

     If the MallocStackLogging environment variable was set when the target process was launched, stringdups
     also displays stack backtraces or call trees showing where all the blocks with a particular grouping of
     content were allocated.

     stringdups gathers the content of blocks of various types including:

     •   C strings (composed of UTF8 characters, null terminated, of any length)
     •   Pascal strings (composed of UTF8 characters with length byte at start, no longer than 255 charac-ters, characters,
         ters, not necessarily null terminated)
     •   NSString of all types (immutable, mutable, UTF8, Unicode).  Malloc blocks which are the storage
         blocks for non-inline or mutable NSString's are listed separately.  The string content is shown for
         both but the block sizes accurately show what is allocated in the malloc heap for that particular
         chunk of storage.
     •   NSDate
     •   NSNumber
     •   NSPathStore2  (Cocoa's representation of file paths)
     •   item counts for collection classes such as NSArray, NSSet, and NSDictionary

     -minimumCount count  Only print information for object descriptions which appear at least count times
                          in the target process.  The default minimum count is 2.  To see all strings in the
                          target process, use 1 or use 'heap <pid> -addresses all'.

     -stringsOnly         Only print information for objects that have string content such as C or Pascal
                          strings, or NSString.

     -nostacks            Do not print stack backtraces or call trees even if the target process has the
                          MallocStackLogging environment variable set.

     -callTrees           If stack bactraces are available, then by default all the object descriptions for
                          a particular stack backtrace are consolidated together.  However if this argument
                          is passed then the output is consolidated by each particular string and a call
                          tree is displayed showing the allocation backtraces of all occurrences of objects
                          with that description.  This output can be very lengthy if minimumCount is a low
                          value, because the same call tree may be displayed many times.

     -invertCallTrees     Same as except that the call trees are printed from hottest to coldest stack
                          frame, so the leaf malloc call appears first.

     heap(1), leaks(1), malloc_history(1), vmmap(1), DevToolsSecurity(1)

BSD                              July 21, 2011                             BSD

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