Valgrind

usage: valgrind [options] prog-and-args
 tool-selection option, with default in [ ]:
 --tool=<name> use the Valgrind tool named <name> [memcheck]
 basic user options for all Valgrind tools, with defaults in [ ]:
 -h --help show this message
 --help-debug show this message, plus debugging options
 --help-dyn-options show the dynamically changeable options
 --version show version
 -q --quiet run silently; only print error msgs
 -v --verbose be more verbose -- show misc extra info
 --trace-children=no|yes Valgrind-ise child processes (follow execve)? [no]
 --trace-children-skip=patt1,patt2,... specifies a list of executables
 that --trace-children=yes should not trace into
 --trace-children-skip-by-arg=patt1,patt2,... same as --trace-children-skip=
 but check the argv[] entries for children, rather
 than the exe name, to make a follow/no-follow decision
 --child-silent-after-fork=no|yes omit child output between fork & exec? [no]
 --vgdb=no|yes|full activate gdbserver? [yes]
 full is slower but provides precise watchpoint/step
 --vgdb-error=<number> invoke gdbserver after <number> errors [999999999]
 to get started quickly, use --vgdb-error=0
 and follow the on-screen directions
 --vgdb-stop-at=event1,event2,... invoke gdbserver for given events [none]
 where event is one of:
 startup exit abexit valgrindabexit all none
 --track-fds=no|yes|all track open file descriptors? [no]
 all includes reporting stdin, stdout and stderr
 --time-stamp=no|yes add timestamps to log messages? [no]
 --log-fd=<number> log messages to file descriptor [2=stderr]
 --log-file=<file> log messages to <file>
 --log-socket=ipaddr:port log messages to socket ipaddr:port
 --enable-debuginfod=no|yes query debuginfod servers for missing
 debuginfo [yes]
 user options for Valgrind tools that report errors:
 --xml=yes emit error output in XML (some tools only)
 --xml-fd=<number> XML output to file descriptor
 --xml-file=<file> XML output to <file>
 --xml-socket=ipaddr:port XML output to socket ipaddr:port
 --xml-user-comment=STR copy STR verbatim into XML output
 --demangle=no|yes automatically demangle C++ names? [yes]
 --num-callers=<number> show <number> callers in stack traces [12]
 --error-limit=no|yes stop showing new errors if too many? [yes]
 --exit-on-first-error=no|yes exit code on the first error found? [no]
 --error-exitcode=<number> exit code to return if errors found [0=disable]
 --error-markers=<begin>,<end> add lines with begin/end markers before/after
 each error output in plain text mode [none]
 --show-error-list=no|yes show detected errors list and
 suppression counts at exit [no]
 -s same as --show-error-list=yes
 --keep-debuginfo=no|yes Keep symbols etc for unloaded code [no]
 This allows saved stack traces (e.g. memory leaks)
 to include file/line info for code that has been
 dlclose'd (or similar)
 --show-below-main=no|yes continue stack traces below main() [no]
 --default-suppressions=yes|no
 load default suppressions [yes]
 --suppressions=<filename> suppress errors described in <filename>
 --gen-suppressions=no|yes|all print suppressions for errors? [no]
 --input-fd=<number> file descriptor for input [0=stdin]
 --dsymutil=no|yes run dsymutil on Mac OS X when helpful? [yes]
 --max-stackframe=<number> assume stack switch for SP changes larger
 than <number> bytes [2000000]
 --main-stacksize=<number> set size of main thread's stack (in bytes)
 [min(max(current 'ulimit' value,1MB),16MB)]
 user options for Valgrind tools that replace malloc:
 --alignment=<number> set minimum alignment of heap allocations [16]
 --redzone-size=<number> set minimum size of redzones added before/after
 heap blocks (in bytes). [16]
 --xtree-memory=none|allocs|full profile heap memory in an xtree [none]
 and produces a report at the end of the execution
 none: no profiling, allocs: current allocated
 size/blocks, full: profile current and cumulative
 allocated size/blocks and freed size/blocks.
 --xtree-memory-file=<file> xtree memory report file [xtmemory.kcg.%p]
 uncommon user options for all Valgrind tools:
 --fullpath-after= (with nothing after the '=')
 show full source paths in call stacks
 --fullpath-after=string like --fullpath-after=, but only show the
 part of the path after 'string'. Allows removal
 of path prefixes. Use this flag multiple times
 to specify a set of prefixes to remove.
 --extra-debuginfo-path=path absolute path to search for additional
 debug symbols, in addition to existing default
 well known search paths.
 --debuginfo-server=ipaddr:port also query this server
 (valgrind-di-server) for debug symbols
 --allow-mismatched-debuginfo=no|yes [no]
 for the above two flags only, accept debuginfo
 objects that don't "match" the main object
 --smc-check=none|stack|all|all-non-file [all-non-file]
 checks for self-modifying code: none, only for
 code found in stacks, for all code, or for all
 code except that from file-backed mappings
 --read-inline-info=yes|no read debug info about inlined function calls
 and use it to do better stack traces.
 [yes] on Linux/Android/Solaris for the tools
 Memcheck/Massif/Helgrind/DRD only.
 [no] for all other tools and platforms.
 --read-var-info=yes|no read debug info on stack and global variables
 and use it to print better error messages in
 tools that make use of it (Memcheck, Helgrind,
 DRD) [no]
 --vgdb-poll=<number> gdbserver poll max every <number> basic blocks [5000]
 --vgdb-shadow-registers=no|yes let gdb see the shadow registers [no]
 --vgdb-prefix=<prefix> prefix for vgdb FIFOs [/tmp/vgdb-pipe]
 --run-libc-freeres=no|yes free up glibc memory at exit on Linux? [yes]
 --run-cxx-freeres=no|yes free up libstdc++ memory at exit on Linux
 and Solaris? [yes]
 --sim-hints=hint1,hint2,... activate unusual sim behaviours [none]
 where hint is one of:
 lax-ioctls lax-doors fuse-compatible enable-outer
 no-inner-prefix no-nptl-pthread-stackcache fallback-llsc none
 --fair-sched=no|yes|try schedule threads fairly on multicore systems [no]
 --kernel-variant=variant1,variant2,...
 handle non-standard kernel variants [none]
 where variant is one of:
 bproc android-no-hw-tls
 android-gpu-sgx5xx android-gpu-adreno3xx none
 --merge-recursive-frames=<number> merge frames between identical
 program counters in max <number> frames) [0]
 --num-transtab-sectors=<number> size of translated code cache [32]
 more sectors may increase performance, but use more memory.
 --avg-transtab-entry-size=<number> avg size in bytes of a translated
 basic block [0, meaning use tool provided default]
 --aspace-minaddr=0xPP avoid mapping memory below 0xPP [guessed]
 --valgrind-stacksize=<number> size of valgrind (host) thread's stack
 (in bytes) [1048576]
 --show-emwarns=no|yes show warnings about emulation limits? [no]
 --require-text-symbol=:sonamepattern:symbolpattern abort run if the
 stated shared object doesn't have the stated
 text symbol. Patterns can contain ? and *.
 --soname-synonyms=syn1=pattern1,syn2=pattern2,... synonym soname
 specify patterns for function wrapping or replacement.
 To use a non-libc malloc library that is
 in the main exe: --soname-synonyms=somalloc=NONE
 in libxyzzy.so: --soname-synonyms=somalloc=libxyzzy.so
 --sigill-diagnostics=yes|no warn about illegal instructions? [yes]
 --unw-stack-scan-thresh=<number> Enable stack-scan unwind if fewer
 than <number> good frames found [0, meaning "disabled"]
 NOTE: stack scanning is only available on arm-linux.
 --unw-stack-scan-frames=<number> Max number of frames that can be
 recovered by stack scanning [5]
 --resync-filter=no|yes|verbose [yes on MacOS, no on other OSes]
 attempt to avoid expensive address-space-resync operations
 --max-threads=<number> maximum number of threads that valgrind can
 handle [500]
 user options for Memcheck:
 --leak-check=no|summary|full search for memory leaks at exit? [summary]
 --leak-resolution=low|med|high differentiation of leak stack traces [high]
 --show-leak-kinds=kind1,kind2,.. which leak kinds to show?
 [definite,possible]
 --errors-for-leak-kinds=kind1,kind2,.. which leak kinds are errors?
 [definite,possible]
 where kind is one of:
 definite indirect possible reachable all none
 --leak-check-heuristics=heur1,heur2,... which heuristics to use for
 improving leak search false positive [all]
 where heur is one of:
 stdstring length64 newarray multipleinheritance all none
 --show-reachable=yes same as --show-leak-kinds=all
 --show-reachable=no --show-possibly-lost=yes
 same as --show-leak-kinds=definite,possible
 --show-reachable=no --show-possibly-lost=no
 same as --show-leak-kinds=definite
 --xtree-leak=no|yes output leak result in xtree format? [no]
 --xtree-leak-file=<file> xtree leak report file [xtleak.kcg.%p]
 --undef-value-errors=no|yes check for undefined value errors [yes]
 --track-origins=no|yes show origins of undefined values? [no]
 --partial-loads-ok=no|yes too hard to explain here; see manual [yes]
 --expensive-definedness-checks=no|auto|yes
 Use extra-precise definedness tracking [auto]
 --freelist-vol=<number> volume of freed blocks queue [20000000]
 --freelist-big-blocks=<number> releases first blocks with size>= [1000000]
 --workaround-gcc296-bugs=no|yes self explanatory [no]. Deprecated.
 Use --ignore-range-below-sp instead.
 --ignore-ranges=0xPP-0xQQ[,0xRR-0xSS] assume given addresses are OK
 --ignore-range-below-sp=<number>-<number> do not report errors for
 accesses at the given offsets below SP
 --malloc-fill=<hexnumber> fill malloc'd areas with given value
 --free-fill=<hexnumber> fill free'd areas with given value
 --keep-stacktraces=alloc|free|alloc-and-free|alloc-then-free|none
 stack trace(s) to keep for malloc'd/free'd areas [alloc-and-free]
 --show-mismatched-frees=no|yes show frees that don't match the allocator? [yes]
 Extra options read from ~/.valgrindrc, $VALGRIND_OPTS, ./.valgrindrc
 Memcheck is Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al.
 Valgrind is Copyright (C) 2000-2017, and GNU GPL'd, by Julian Seward et al.
 LibVEX is Copyright (C) 2004-2017, and GNU GPL'd, by OpenWorks LLP et al.
 Bug reports, feedback, admiration, abuse, etc, to: www.valgrind.org.

==3577== Memcheck, a memory error detector
==3577== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al.
==3577== Using Valgrind-3.24.1.GIT and LibVEX; rerun with -h for copyright info
==3577== Command: ./memleak
==3577=わ=わ
10
=わ=わ3577=わ=わ
=わ=わ3577== HEAP SUMMARY:
==3577== in use at exit: 40 bytes in 1 blocks
==3577== total heap usage: 2 allocs, 1 frees, 1,064 bytes allocated
==3577=わ=わ
=わ=わ3577=わ=わ 40 bytes in 1 blocks are definitely lost in loss record 1 of 1
==3577== at 0x4849968: malloc (vg_replace_malloc.c:446)
==3577== by 0x1091AE: main (memleak.c:4)
==3577==
==3577== LEAK SUMMARY:
==3577== definitely lost: 40 bytes in 1 blocks
==3577== indirectly lost: 0 bytes in 0 blocks
==3577== possibly lost: 0 bytes in 0 blocks
==3577== still reachable: 0 bytes in 0 blocks
==3577== suppressed: 0 bytes in 0 blocks
==3577==
==3577== For lists of detected and suppressed errors, rerun with: -s
==3577== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

==3903== Memcheck, a memory error detector
==3903== Copyright (C) 2002-2024, and GNU GPL'd, by Julian Seward et al.
==3903== Using Valgrind-3.24.1.GIT and LibVEX; rerun with -h for copyright info
==3903== Command: ./uninitialized
==3903==
==3903== Use of uninitialised value of size 8
==3903== at 0x109189: main (uninitialized.c:3)
==3903== Uninitialised value was created by a stack allocation
==3903== at 0x109179: main (uninitialized.c:1)
==3903=わ=わ
1179403647
=わ=わ3903=わ=わ
=わ=わ3903== HEAP SUMMARY:
==3903== in use at exit: 0 bytes in 0 blocks
==3903== total heap usage: 1 allocs, 1 frees, 1,024 bytes allocated
==3903==
==3903== All heap blocks were freed -- no leaks are possible
==3903==
==3903== For lists of detected and suppressed errors, rerun with: -s
==3903== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)