stringdups(1) General Commands Manual stringdups(1)
NAME
stringdups – Identify duplicate strings or other objects in malloc blocks
of a target process
SYNOPSIS
stringdups [-minimumCount count] [-stringsOnly] [-nostacks] [-callTrees]
[-invertCallTrees]
pid | partial-executable-name | memory-graph-file
DESCRIPTION
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 size.
stringdups requires one argument -- either the process ID or the full or
partial executable name of the process to examine, or the pathname of a
memory graph file generated by leaks. When generating a memory graph with
leaks for use with stringdups it is necessary to use the -fullContent
argument to include labels describing the contents of memory.
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 characters, 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)
• __NSMallocBlock__ For these, stringdups shows the symbol name of the
code block (^) that this storage is associated with. If debug
information is available, the source path and line number of the code
block are also shown.
• item counts for collection classes such as NSArray, NSSet, and
NSDictionary
OPTIONS
-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 backtraces 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 -callTrees except that the call trees are
printed from hottest to coldest stack frame, so the
leaf malloc call appears first.
SEE ALSO
heap(1), leaks(1), malloc_history(1), vmmap(1), DevToolsSecurity(1)
macOS 15.2 July 2, 2016 macOS 15.2