Provided by: lcov_2.1-1_all bug

NAME

       lcov - a graphical GCOV front-end

SYNOPSIS

       Capture coverage data tracefile (from compiler-generated data):

          lcov -c|--capture
              [-d|--directory directory] [-k|--kernel-directory directory]
              [-o|--output-file tracefile] [-t|--test-name testname]
              [-b|--base-directory directory]
              [--build-directory directory]
              [--source-directory directory]
              [-i|--initial]
              [--all]]
              [--gcov-tool tool]
              [--branch-coverage]
              [--demangle-cpp [param]]
              [--checksum] [--no-checksum] [--no-recursion] [-f|--follow]
              [--compat-libtool] [--no-compat-libtool]
              [--ignore-errors errors]
              [--preserve]   [--to-package   package]   [--from-package  package]  [--no-markers]
              [--external] [--no-external]
              [--compat mode=on|off|auto]
              [--version-script script_file]
              [--resolv--script script_file]
              [--comment comment_string]

       Generate tracefile (from compiler-generated data) with all counter values set to zero:

          lcov -z|--zerocounters
              [-d|--directory directory] [--no-recursion] [-f|--follow]

       Show coverage counts recorded in previously generated tracefile:

          lcov -l|--list tracefile
              [--list-full-path] [--no-list-full-path]

       Aggregate multiple coverage tracefiles into one:

          lcov -a|--add-tracefile tracefile_pattern
              [-o|--output-file tracefile]
              [--prune-tests]
              [--forget-test-names]
              [--map-functions]
              [--branch-coverage]
              [--checksum] [--no-checksum]

          Depending on your use model, it may not be necessary to create aggregate coverage  data
          files.   For  example, if your regression tests are split into multiple suites, you may
          want to keep separate suite data and to compare both per-suite  and  aggregate  results
          over time.  genhtml allows you specify tracefiles via one or more glob patterns - which
          enables you generate aggregate reports without explicitly generating  aggregated  trace
          files.  See the genhtml man page.

       Generate  new  tracefile  from  existing  tracefile, keeping only data from files matching
       pattern:

          lcov -e|--extract tracefile pattern
              [-o|--output-file tracefile] [--checksum] [--no-checksum]

       Generate new tracefile from existing tracefile, removing data from files matching pattern:

          lcov -r|--remove tracefile pattern
              [-o|--output-file tracefile] [--checksum] [--no-checksum]

       Generate new tracefile from existing tracefiles by performing set operations  on  coverage
       data:

          lcov --intersect rh_glob_pattern
              [-o|--output-file tracefile]
              lh_glob_pattern

              The output will reflect
                (union  of  files  matching  lh_glob_patterns) intersect (union of files matching
                rh_glob_patterns)
              such that coverpoints found in both sets are merged  (summed)  whereas  coverpoints
              found  in  only one set are dropped.  Note that branch blocks are defined to be the
              same if and only if their block ID and the associated branch expressions  list  are
              identical.   Functions  are  defined  to be the same if their name and location are
              identical.

          lcov --subtract rh_glob_pattern
              [-o|--output-file tracefile]
              lh_glob_pattern

              The output will reflect
                (union of files matching lh_glob_patterns)  subtract  (union  of  files  matching
                rh_glob_patterns)
              such  that  coverpoints  found only in the set on the left will be retained and all
              others are dropped.

       Generate new tracefile from existing tracefile, modifying line  numbers  as  indicated  in
       diff file:

          lcov --diff tracefile diff
              [-o|--output-file tracefile] [--checksum] [--no-checksum]
              [--convert-filenames] [--strip depth] [--path path]

       Summarize tracefile content:

          lcov --summary tracefile
              [--fail-under-lines percentage]

       Print version or help message and exit:

          lcov [-h|--help] [--version]

       Common lcov options - supported by all the above use cases:

          lcov [--keep-going]
               [--filter type]
               [-q|--quiet]
               [-v|--verbose]
               [--comment comment_string]
               [--debug]
               [--parallel|-j [integer]]
               [--memory integer_num_Mb]
               [--tempdir dirname]
               [--branch-coverage]
               [--config-file config-file] [--rc keyword=value]
               [--include glob_pattern]
               [--exclude glob_pattern]
               [--erase-functions regexp_pattern]
               [--substitute regexp_pattern]
               [--omit-lines regexp_pattern]

DESCRIPTION

       lcov  is  a  graphical  front-end  for GCC's coverage testing tool gcov. It collects line,
       function and branch coverage data  for  multiple  source  files  and  creates  HTML  pages
       containing  the  source  code  annotated with coverage information.  It also adds overview
       pages for easy navigation within the file structure.

       Use lcov to collect coverage data and genhtml to create  HTML  pages.  Coverage  data  can
       either  be  collected  from  the  currently  running  Linux  kernel  or  from a user space
       application. To do this, you have to complete the following preparation steps:

       For Linux kernel coverage:
              Follow   the   setup   instructions    for    the    gcov-kernel    infrastructure:
              https://docs.kernel.org/dev-tools/gcov.html

       For user space application coverage:
          Compile   the   application   with   GCC   using   the   options  "-fprofile-arcs"  and
          "-ftest-coverage" or "--coverage".

       Please note that this man page refers to the output format of  lcov  as  ".info  file"  or
       "tracefile" and that the output of GCOV is called ".da file".

       Also note that when printing percentages, 0% and 100% are only printed when the values are
       exactly 0% and 100% respectively. Other values which would conventionally be rounded to 0%
       or  100% are instead printed as nearest non-boundary value. This behavior is in accordance
       with that of the gcov(1) tool.

       By default, lcov and related tools generate and collect line and function  coverage  data.
       Branch  data  is  not  collected  or displayed by default; all tools support the --branch-
       coverage option to enable branch coverage - or you can permanently enable branch  coverage
       by  adding  the  appropriate  settings to your personal, group, or site lcov configuration
       file.  See man lcovrc(5) for details.

OPTIONS

       -a tracefile_pattern
       --add-tracefile tracefile_pattern
              Add contents of all files matching glob pattern tracefile_pattern.

              Specify several tracefiles using  the  -a  switch  to  combine  the  coverage  data
              contained  in  these  files  by  adding  up  execution counts for matching test and
              filename combinations.

              The result of the add  operation  will  be  written  to  stdout  or  the  tracefile
              specified with -o.

              Only  one  of   -z,  -c,  -a, -e, -r, -l, --diff or --summary may be specified at a
              time.

       -b directory
       --base-directory directory
              Use directory as base directory for relative paths.

              Use this option to specify the base directory  of  a  build-environment  when  lcov
              produces error messages like:

                     ERROR:          could          not          read         source         file
                     /home/user/project/subdir1/subdir2/subdir1/subdir2/file.c

              In this example, use /home/user/project as base directory.

              This option is required when using lcov on projects built with libtool  or  similar
              build  environments  that  work with a base directory, i.e. environments, where the
              current working directory when invoking the compiler is not the same  directory  in
              which the source code file is located.

              Note that this option will not work in environments where multiple base directories
              are used. In that case use configuration file setting geninfo_auto_base=1 (see  man
              lcovrc(5) ).

       --build-directory build_directory
              search  for  .gcno  data  files  from  build_directory  rather than adjacent to the
              corresponding .gcda file.

              See man geninfo(1)) for details.

       --source-directory dirname
              Add 'dirname' to the list of places to look for source files.

              For relative source file paths listed in e.g.  paths found in tracefile,  or  found
              in  gcov output during --capture - possibly after substitutions have been applied -
              lcov
               will first look for the path from 'cwd' (where genhtml was invoked) and then  from
              each  alternate directory name in the order specified.  The first location matching
              location is used.

              This option can be specified multiple times, to add more directories to the  source
              search path.

       -c
       --capture
              Capture runtime coverage data.

              By  default  captures  the current kernel execution counts and writes the resulting
              coverage data to the standard output. Use the --directory option to capture  counts
              for a user space program.

              The  result  of  the  capture  operation will be written to stdout or the tracefile
              specified with -o.

              When combined with the --all flag, both runtime and compile-time coverage  will  be
              extracted in one step.  See the description of the --initial flag, below.

              See  man  geninfo(1))  for  more  details  about  the capture process and available
              options and parameters.

              Only one of  -z, -c, -a, -e, -r, -l, --diff or --summary  may  be  specified  at  a
              time.

       --branch-coverage
              Collect and/or retain branch coverage data.

              This  is  equivalent  to  using the option "--rc branch_coverage=1"; the option was
              added to better match the genhml interface.

       --checksum
       --no-checksum
              Specify whether to generate checksum data when writing tracefiles and/or to  verify
              matching checksums when combining trace files.

              Use  --checksum  to  enable  checksum  generation  or  --no-checksum to disable it.
              Checksum generation is disabled by default.

              When checksum generation is enabled, a checksum will be generated for  each  source
              code  line  and  stored along with the coverage data. This checksum will be used to
              prevent attempts to combine coverage data from different source code versions.

              If you don't work with different source code versions, disable this option to speed
              up coverage data processing and to reduce the size of tracefiles.

              Note  that this options is somewhat subsumed by the --version-script option - which
              does something similar, but at the 'whole file' level.

       --compat mode=value[,mode=value,...]
              Set compatibility mode.

              Use --compat to specify that lcov should enable one  or  more  compatibility  modes
              when  capturing coverage data. You can provide a comma-separated list of mode=value
              pairs to specify the values for multiple modes.

              Valid values are:

              on
                     Enable compatibility mode.
              off
                     Disable compatibility mode.
              auto
                     Apply auto-detection to determine if compatibility mode  is  required.  Note
                     that auto-detection is not available for all compatibility modes.

              If no value is specified, 'on' is assumed as default value.

              Valid modes are:

              libtool
                     Enable  this  mode if you are capturing coverage data for a project that was
                     built using the libtool mechanism. See also --compat-libtool.

                     The default value for this setting is 'on'.

              hammer
                     Enable this mode if you are capturing coverage data for a project  that  was
                     built using a version of GCC 3.3 that contains a modification (hammer patch)
                     of later GCC versions. You can identify a modified GCC 3.3 by  checking  the
                     build  directory  of  your project for files ending in the extension '.bbg'.
                     Unmodified versions of GCC 3.3 name these files '.bb'.

                     The default value for this setting is 'auto'.

              split_crc
                     Enable this mode if you are capturing coverage data for a project  that  was
                     built  using  a  version  of  GCC  4.6  that  contains a modification (split
                     function checksums) of later  GCC  versions.  Typical  error  messages  when
                     running  lcov  on  coverage  data  produced by such GCC versions are ´out of
                     memory' and 'reached unexpected end of file'.

                     The default value for this setting is 'auto'

       --compat-libtool
       --no-compat-libtool
              Specify whether to enable libtool compatibility mode.

              Use --compat-libtool to enable libtool compatibility mode or --no-compat-libtool to
              disable it. The libtool compatibility mode is enabled by default.

              When  libtool  compatibility mode is enabled, lcov will assume that the source code
              relating to a .da file located in a directory named ".libs" can  be  found  in  its
              parent directory.

              If  you  have  directories  named  ".libs"  in your build environment but don't use
              libtool, disable this option to prevent problems when capturing coverage data.

       --config-file config-file
              Specify a configuration file to use.  See man lcovrc(5) for  details  of  the  file
              format and options.

              When   this  option  is  specified,  neither  the  system-wide  configuration  file
              /etc/lcovrc, nor the per-user configuration file ~/.lcovrc is read.

              This option may be useful when there is a need to run  several  instances  of  lcov
              with different configuration file options in parallel.

              Note that this option must be specified in full - abbreviations are not supported.

       --convert-filenames
              Convert filenames when applying diff.

              Use  this  option  together  with --diff to rename the file names of processed data
              sets according to the data provided by the diff.

       --diff tracefile difffile
              Convert coverage data in tracefile using source code diff file difffile.

              Use this option if you want to merge  coverage  data  from  different  source  code
              levels  of  a program, e.g. when you have data taken from an older version and want
              to combine it with data from a more current version.  lcov will try to  map  source
              code  lines  between  those  versions  and  adjust  the coverage data respectively.
              difffile needs to be in unified format, i.e. it has to be created  using  the  "-u"
              option of the diff tool.

              Note  that  lines  which  are not present in the old version will not be counted as
              instrumented, therefore tracefiles resulting from  this  operation  should  not  be
              interpreted  individually  but  together with other tracefiles taken from the newer
              version. Also keep in mind that converted coverage data should  only  be  used  for
              overview purposes as the process itself introduces a loss of accuracy.

              The  result  of  the  diff  operation  will  be  written to stdout or the tracefile
              specified with -o.

              Only one of  -z, -c, -a, -e, -r, -l, --diff or --summary  may  be  specified  at  a
              time.

       -d directory
       --directory directory
              Use .da files in directory instead of kernel.

              If  you  want to work on coverage data for a user space program, use this option to
              specify the location where the program was compiled (that's where the counter files
              ending with .da will be stored).

              Note that you may specify this option more than once.

       --exclude pattern
              Exclude source files matching pattern.

              Use this switch if you want to exclude coverage data for a particular set of source
              files matching any of the given patterns. Multiple patterns  can  be  specified  by
              using multiple --exclude command line switches. The patterns will be interpreted as
              shell wildcard patterns (note that they may  need  to  be  escaped  accordingly  to
              prevent the shell from expanding them first).

              Note: The pattern must be specified to match the absolute path of each source file.
              If you specify a pattern which does not seem to be correctly applied -  files  that
              you  expected  to be excluded still appear in the output - you can look for warning
              messages in the log file.  lcov will emit a warning for every pattern which is  not
              applied at least once.

              Can  be  combined  with  the --include command line switch. If a given file matches
              both the include pattern and the exclude pattern, the  exclude  pattern  will  take
              precedence.

       --erase-functions regexp
              Exclude  coverage  data  from lines which fall within a function whose name matches
              the supplied regexp.  Note that this is a mangled or demangled name,  depending  on
              whether the --demangle-cpp option is used or not.

              Note  that  this  option requires that you use a gcc version which is new enough to
              support function begin/end line reports or that you configure the  tool  to  derive
              the required dta - see the derive_function_end_line discussion in man lcovrc(5).

       --substitute regexp_pattern
              Apply  Perl  regexp  regexp_pattern  to  source file names found during processing.
              This is useful, for example, when the path name reported by  gcov  does  not  match
              your  source  layout and the file is not found, or in more complicated environments
              where the build directory structure does not match the source code  layout  or  the
              layout in the projects's revision control system.

              Use  this option in situations where geninfo cannot find the correct path to source
              code files of a project. By providing a regexp_pattern in Perl  regular  expression
              format  (see man perlre(1) ), you can instruct geninfo to remove or change parts of
              the incorrect source path.  Also see the --resolve-script option.

              One or more --substitution patterns and/or a  --resolve-script  may  be  specified.
              When  multiple  paterns  are  specified,  they  are  applied in the order specifed,
              substitution patterns first followed by the  resolve  callback.   The  file  search
              order is:

                     1. Look for file name (unmodifed).
                        If the file exits: return it.

                     2. Apply  all  substitution  patterns  in  order  -  the result of the first
                        pattern is used as the input of the second pattern, and so forth.
                        If a file corresponding to the resulting name exists:  return it.

                     3. Apply the 'resolve' callback ot the final result of pattern substituions.
                        If a file corresponding to the resulting name exists:  return it.

                     4. Otherwise:  return original (unmodified) file name.
                        Depending on context, the unresolved file name may or may not  result  in
                        an error.

              Substitutions are used in multiple contexts by lcov/genhtml/geninfo:

                     -  during  --capture,  applied  to source file names found in gcov-generated
                        coverage data files (see man gcov(1) ).

                     -  during --capture, applied to alternate --build-dir  paths,  when  looking
                        for  the  .gcno  (compile  time)  data  file  corresponding to some .gcda
                        (runtime) data file.

                     -  applied to file names found in lcov data files (".info"  files)  -  e.g.,
                        during lcov data aggregation or HTML and text report generation.
                        For  example,  substituted  names are used to find source files for text-
                        based filtering (see the --filter  section,  below)  and  are  passed  to
                        --version-script, --annotate-script, and -criteria-script callbacks.

                     -  applied to file names found in the --diff-file passed to genhtml.

              Example:

              1. When geninfo reports that it cannot find source file

                  /path/to/src/.libs/file.c

              while the file is actually located in

                  /path/to/src/file.c

              use the following parameter:

                  --substitute 's#/.libs##g'

              This will remove all "/.libs" strings from the path.

              2. When geninfo reports that it cannot find source file

                  /tmp/build/file.c

              while the file is actually located in

                  /usr/src/file.c

              use the following parameter:

                  --substitute 's#/tmp/build#/usr/src#g'

              This will change all "/tmp/build" strings in the path to "/usr/src".

       --omit-lines regexp
              Exclude coverage data from lines whose content matches regexp.

              Use  this  switch  if  you  want  to exclude line and branch coverage data for some
              particular constructs in  your  code  (e.g.,  some  complicated  macro).   Multiple
              patterns can be specified by using multiple --omit-lines command line switches. The
              regexp will be interpreted as perl regular expressions (note that they may need  to
              be  escaped  accordingly  to  prevent the shell from expanding them first).  If you
              want the pattern to explicitly match from the start or end of the line, your regexp
              should start and/or end with "^" and/or "$".

              Note  that  the  lcovrc  config  file setting lcov_excl_line = regexp is similar to
              --omit-lines.  --omit-lines is useful if there are multiple  teams  each  of  which
              want  to  exclude  certain patterns.  --omit-lines is additive and can be specified
              across multiple config files whereas each  call  to  lcov_excl_line  overrides  the
              previous value - and thus teams must coordinate.

       --external
       --no-external
              Specify whether to capture coverage data for external source files.

              External  source  files  are  files which are not located in one of the directories
              specified by --directory or --base-directory. Use --external  to  include  external
              source files while capturing coverage data or --no-external to ignore this data.

              Data for external source files is included by default.

       --forget-test-names
              If non-zero, ignore testcase names in .info file - i.e., treat all coverage data as
              if it came from the same testcase.  This may improve performance and reduce  memory
              consumption  if  user  does  not  need  per-testcase  coverage  summary in coverage
              reports.

              This option can also be configured permanently using the configuration file  option
              forget_testcase_names.

       --prune-tests
              Determine list of unique tracefiles.

              Use this option to determine a list of unique tracefiles from the list specified by
              --add-tracefile.  A tracefile is  considered  to  be  unique  if  it  is  the  only
              tracefile that:

                     1. contains data for a specific source file

                     2. contains data for a specific test case name

                     3. contains non-zero coverage data for a specific line, function or branch

              Note  that  the  list of retained files may depend on the order they are processed.
              For example, if A and B contain identical coverage data, then the first one we  see
              will  be  retained  and  the  second  will be pruned.  The file processing order is
              nondeterministic when the --parallel option is used  -  implying  that  the  pruned
              result may differ from one execution to the next in this case.

              --prune-testsmustbespecifiedtogetherwith  --add-tracefile.   When  specified,  lcov
              will emit the list of unique files rather than combined tracefile data.

       --map-functions
              List tracefiles with non-zero coverage for each function.

              Use this option to determine the list of tracefiles that contain non-zero  coverage
              data for each function from the list of tracefiles specified by --add-tracefile.

              This  option must be specified together with --add-tracefile.  When specified, lcov
              will emit the list of functions and  associated  tracefiles  rather  than  combined
              tracefile data.

       --version-script script

              Use  script to get a source file's version ID from revision control when extracting
              data and to compare version IDs for the purpose  of  error  checking  when  merging
              .info files.

              See the genhtml man page for more details on the version script.

       --resolve-script script
              Use  script  to  find  the file path for some source file which appears in an input
              data file if the file  is  not  found  after  applying  --substitute  patterns  and
              searching   the   --source-directory  list.   This  option  is  equivalent  to  the
              resolve_script config file option. See man lcovrc(5) for details.

       --comment comment_string

              Append comment_string to list of comments emitted into output  result  file.   This
              option  may  be  specified  multiple times.  Comments are printed at the top of the
              file, in the order they were specified.

              Comments may be useful to document the conditions under which the  trace  file  was
              generated:  host, date, environment, etc.

              Note  that  this  option  has  no  effect for lcov overations which do not write an
              output result file: --list --summary, --prune-tests, and --map-functions.

              See the geninfo man page for a description of the  comment  format  in  the  result
              file.

       -e tracefile pattern
       --extract tracefile pattern
              Extract data from tracefile.

              Use  this  switch if you want to extract coverage data for only a particular set of
              files from a tracefile. Additional command line parameters will be  interpreted  as
              shell  wildcard  patterns  (note  that  they  may need to be escaped accordingly to
              prevent the shell from expanding them first).  Every file entry in tracefile  which
              matches at least one of those patterns will be extracted.

              Note: The pattern must be specified to match the absolute path of each source file.

              The  result  of  the  extract  operation will be written to stdout or the tracefile
              specified with -o.

              Only one of  -z, -c, -a, -e, -r, -l, --diff or --summary  may  be  specified  at  a
              time.

       -f
       --follow
              Follow links when searching for .da files.

       --from-package package
              Use .da files in package instead of kernel or directory.

              Use  this  option  if  you  have  separate  machines for build and test and want to
              perform the .info file creation on the build machine.  See  --to-package  for  more
              information.

       --gcov-tool tool
              Specify the location of the gcov tool.

              See the geninfo man page for more details.

       -h
       --help
              Print a short help text, then exit.

       --include pattern
              Include source files matching pattern.

              Use  this  switch if you want to include coverage data for only a particular set of
              source files matching any of the given patterns. Multiple patterns can be specified
              by using multiple --include command line switches. The patterns will be interpreted
              as shell wildcard patterns (note that they may need to be  escaped  accordingly  to
              prevent the shell from expanding them first).

              Note: The pattern must be specified to match the absolute path of each source file.

              If  you  specify a pattern which does not seem to be correctly applied - files that
              you expected to be included in the output do not appear -  lcov  will  generate  an
              error  message  of  type  'unused'.  See the --ignore-errors option for how to make
              lcov ignore the error or turn it into a warning.

       --ignore-errors errors
              Specify a list of errors after which to continue processing.

              Use this option to specify a list of one or more classes of errors after which lcov
              should continue processing instead of aborting.  Note that the tool will generate a
              warning (rather than a fatal error) unless you  ignore  the  error  two  (or  more)
              times:
                     lcov ... --ignore-errors source,source ...

              errors can be a comma-separated list of the following keywords:

              branch:
                 branch  ID  (2nd  field in the .info file 'BRDA' entry) does not follow expected
                 integer sequence.

              callback:
                 Version script error.

              child:
                 child process returned non-zero exit code  during  --parallel  execution.   This
                 typically  indicates  that  the  child  encountered  an error:  see the log file
                 immediately above this message.  In contrast:  the parallel error  indicates  an
                 unexpected/unhandled  exception  in  the  child  process  - not a 'typical' lcov
                 error.

              corrupt:
                 corrupt/unreadable file found.

              count:
                 An excessive number of messages of some class have been  reported  -  subsequent
                 messages  of  that  type will be suppressed.  The limit can be controlled by the
                 'max_message_count' variable. See man lcovrc(5).

              deprecated:
                 You are using a deprecated option.  This option will be removed in  an  upcoming
                 release - so you should change your scripts now.

              empty:
                 the  .info  data  file  is  empty  (e.g.,  because all the code was 'removed' or
                 excluded.

              excessive:
                 your coverage data contains a suspiciously large 'hit' count which  is  unlikely
                 to  be  correct  -  possibly  indicating  a  bug  in  your  toolchain.   See the
                 excessive_count_threshold section in man lcovrc(5) for details.

              fork:
                 Unable to create child process during --parallel execution.
                 If the message is ignored ( --ignore-errors fork ), then  genhtml  will  wait  a
                 brief period and then retry the failed execution.
                 If you see continued errors, either turn off or reduce parallelism, set a memory
                 limit, or find a larger server to run the task.

              format:
                 unexpected syntax found in .info file.

              gcov:
                 the gcov tool returned with a non-zero return code.

              graph:
                 the graph file could not be found or is corrupted.

              internal:
                 internal tool issue detected.  Please report this bug along with a testcase.

              mismatch:
                 Inconsistent entries found in trace file:

                 •  branch expression (3rd field in the .info file 'BRDA' entry)  of  merge  data
                    does not match, or

                 •  function execution count (FNDA:...) but no function declaration (FN:...).

              missing:
                 File does not exist or is not readable.

              negative:
                 negative 'hit' count found.

                 Note that negative counts may be caused by a known GCC bug - see

                   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68080

                 and  try  compiling  with "-fprofile-update=atomic". You will need to recompile,
                 re-run your tests, and re-capture coverage data.

              package:
                 a required perl package is not installed on your system.  In some cases,  it  is
                 possible to ignore this message and continue - however, certain features will be
                 disabled in that case.

              parallel:
                 various types of errors related to parallelism - i.e., a child process died  due
                 to  an  error.   The  corresponding  error  message  appears  in  the  log  file
                 immediately before the parallel error.

                 If you see an error related to parallel execution that seems invalid, it may  be
                 a  good  idea to remove the --parallel flag and try again.  If removing the flag
                 leads to a different result, please report the issue (along with a testcase)  so
                 that the tool can be fixed.

              parent:
                 the  parent  process  exited while child was active during --parallel execution.
                 This happens when the parent has encountered a fatal error - e.g.  an  error  in
                 some  other  child  which  was  not ignored.  This child cannot continue working
                 without its parent - and so will exit.

              range:
                 Coverage data refers to a line number which is larger than the number  of  lines
                 in  the source file.  This can be caused by a version mismatch or by an issue in
                 the gcov data.

              source:
                 the source code file for a data set could not be found.

              unsupported:
                 the requested feature  is  not  supported  for  this  tool  configuration.   For
                 example,  function  begin/end  line range exclusions use some GCOV features that
                 are not available in older GCC releases.

              unused:
                 the  include/exclude/erase/omit/substitute  pattern  did  not  match  any   file
                 pathnames.

              usage:
                 unsupported usage detected - e.g. an unsupported option combination.

              utility:
                 a tool called during processing returned an error code (e.g., 'find' encountered
                 an unreadable directory).

              version:
                 revision control IDs of the file which we are trying to merge are not the same -
                 line numbering and other information may be incorrect.

              Also  see man lcovrc(5) for a discussion of the 'max_message_count' parameter which
              can be used to control  the  number  of  warnings  which  are  emitted  before  all
              subsequent messages are suppressed.  This can be used to reduce log file volume.

       --keep-going
              Do not stop if error occurs: attempt to generate a result, however flawed.

              This command line option corresponds to the stop_on_error [0|1] lcovrc option.  See
              man lcovrc(5) for more details.

       --preserve
              Preserve intermediate data files generated by various steps in the tool - e.g., for
              debugging.  By default, these files are deleted.

       --filter filters
              Specify  a  list of coverpoint filters to apply to input data.  See the genhtml man
              page for details.

       --demangle-cpp [param]
              Demangle C++ function names.  See the genhtml man page for details.

       -i
       --initial
              Capture initial zero coverage data -  i.e.,  from  the  compile-time  '.gcno'  data
              files.   Also see the --all flag, which tells the tool to capture both compile-time
              ('.gcno') and runtime ('.gcda') data at the same time.

              Run lcov with -c and this option on the directories containing .bb, .bbg  or  .gcno
              files  before  running any test case. The result is a "baseline" coverage data file
              that contains zero coverage for every instrumented line.  Combine  this  data  file
              (using  lcov  -a) with coverage data files captured after a test run to ensure that
              the percentage of total lines covered is correct even  when  not  all  source  code
              files were loaded during the test.

              Recommended procedure when capturing data for a test case:

              1. create baseline coverage data file
                     # lcov -c -i -d appdir -o app_base.info

              2. perform test
                     # appdir/test

              3. create test coverage data file
                     # lcov -c -d appdir -o app_test.info

              4. combine baseline and test coverage data
                     # lcov -a app_base.info -a app_test.info -o app_total.info

              The above 4 steps are equivalent to
                     # lcov --capture --all -o app_total.info -d appdir

              The  combined  compile-  and  runtime  data  will  produce  a different result than
              capturing runtime data alone if your project contains some compilation units  which
              are  not  used  in  any of your testcase executables or shared libraries - that is,
              there are some '.gcno' (compile time) data files that do not have matching  '.gcda'
              (runtime)  data  files.  In that case, the runtime-only report will not contain any
              coverpoints from the unused files, whereas those coverpoints will appear (with  all
              zero 'hit' counts) in the combined report.

              The  --initial flag is ignored except in --capture mode.  The --all flag is ignored
              if the --initial flag is specified.

       -k subdirectory
       --kernel-directory subdirectory
              Capture kernel coverage data only from subdirectory.

              Use this option if you don't want to get coverage data for all of the  kernel,  but
              only for specific subdirectories. This option may be specified more than once.

              Note  that  you  may  need  to  specify  the  full  path to the kernel subdirectory
              depending on the version of the kernel gcov support.

       -l tracefile
       --list tracefile
              List the contents of the tracefile.

              Only one of  -z, -c, -a, -e, -r, -l, --diff or --summary  may  be  specified  at  a
              time.

       --list-full-path
       --no-list-full-path
              Specify whether to show full paths during list operation.

              Use    --list-full-path   to   show   full   paths   during   list   operation   or
              --no-list-full-path to show shortened paths. Paths are shortened by default.

       --no-markers
              Use this option if you want to  get  coverage  data  without  regard  to  exclusion
              markers in the source code file. See geninfo (1) for details on exclusion markers.

       --no-recursion
              Use  this  option if you want to get coverage data for the specified directory only
              without processing subdirectories.

       -o tracefile
       --output-file tracefile
              Write data to tracefile instead of stdout.

              Specify "-" as a filename to use the standard output.

              By convention, lcov-generated coverage  data  files  are  called  "tracefiles"  and
              should have the filename extension ".info".

       --path path
              Strip path from filenames when applying diff.

              Use  this  option  together  with  --diff  to  tell lcov to disregard the specified
              initial path component when matching between tracefile and diff filenames.

       -v
       --verbose
              Increment informational message verbosity.  This is mainly used for  script  and/or
              flow  debugging  -  e.g., to figure out which data file are found, where.  Also see
              the --quiet flag.

              Messages are sent to stdout unless there is no output file (i.e., if  the  coverage
              data is written to stdout rather than to a file) and to stderr otherwise.

       -q
       --quiet
              Decrement informational message verbosity.

              Decreased verbosity will suppress 'progress' messages for example - while error and
              warning messages will continue to be printed.

       --debug
              Increment 'debug messages' verbosity.  This is useful primarily to  developers  who
              want to enhance the lcov tool suite.

       --parallel [ integer ]
       -j [ integer ]
              Specify  parallelism  to  use  during  processing  (maximum  number of forked child
              processes).  If the optional integer parallelism parameter is zero or  is  missing,
              then  use  to  use  up the number of cores on the machine.  Default is not to use a
              single process (no parallelism).
              Also  see  the  memory,  memory_percentage,  max_fork_fails  and  fork_fail_timeout
              entries in man lcovrc(5).

       --memory integer
              Specify  the  maximum  amount  of  memory to use during parallel processing, in Mb.
              Effectively, the process will not fork() if this limit would be exceeded.   Default
              is 0 (zero) - which means that there is no limit.

              This  option may be useful if the compute farm environment imposes strict limits on
              resource utilization such that the job will be killed if it tries to use  too  many
              parallel  children  -  but  the  user  does  now know a priori what the permissible
              maximum is.  This option enables the tool to use maximum parallelism -  up  to  the
              limit imposed by the memory restriction.

              The  configuration  file  memory_percentage  option provided another way to set the
              maximum memory consumption.  See man lcovrc(5) for details.

       --rc keyword=value
              Override a configuration directive.

              Use  this  option  to  specify  a  keyword=value  statement  which  overrides   the
              corresponding  configuration  statement  in  the lcovrc configuration file. You can
              specify this option more than once to override multiple  configuration  statements.
              See man lcovrc(5) for a list of available keywords and their meaning.

       -r tracefile pattern
       --remove tracefile pattern
              Remove data from tracefile.

              Use  this  switch if you want to remove coverage data for a particular set of files
              from a tracefile. Additional command line parameters will be interpreted  as  shell
              wildcard patterns (note that they may need to be escaped accordingly to prevent the
              shell from expanding them first).  Every file entry in tracefile which  matches  at
              least one of those patterns will be removed.

              Note: The pattern must be specified to match the absolute path of each source file.

              The  result  of  the  remove  operation  will be written to stdout or the tracefile
              specified with -o.

              Only one of  -z, -c, -a, -e, -r, -l, --diff or --summary  may  be  specified  at  a
              time.

       --strip depth
              Strip path components when applying diff.

              Use this option together with --diff to tell lcov to disregard the specified number
              of initial directories when matching tracefile and diff filenames.

       --summary tracefile
              Show summary coverage information for the specified tracefile.

              Note that you may specify this option more than once.

              Only one of  -z, -c, -a, -e, -r, -l, --diff or --summary  may  be  specified  at  a
              time.

       --fail-under-lines percentage
              Use  this option together with --summary to tell lcov to exit with a status of 1 if
              the total line coverage is less than percentage.

       -t testname
       --test-name testname
              Specify test name to be stored in the tracefile.

              This name identifies a coverage data set when more than one data set is merged into
              a combined tracefile (see option -a).

              Valid  test  names  can  consist  of  letters,  decimal  digits  and the underscore
              character ("_").

       --to-package package
              Store .da files for later processing.

              Use this option if you have separate machines  for  build  and  test  and  want  to
              perform  the  .info  file  creation  on the build machine. To do this, follow these
              steps:

              On the test machine:
                     - run the test
                     - run lcov -c [-d directory] --to-package file
                     - copy file to the build machine

              On the build machine:
                     - run lcov -c --from-package file [-o and other options]

              This works for both kernel and user space coverage data. Note that you  might  have
              to  specify  the  path  to the build directory using -b with either --to-package or
              --from-package. Note also that the package data must be converted to a  .info  file
              before recompiling the program or it will become invalid.

       --version
              Print version number, then exit.

       -z
       --zerocounters
              Reset all execution counts to zero.

              By  default  tries  to reset kernel execution counts. Use the --directory option to
              reset all counters of a user space program.

              Only one of  -z, -c, -a, -e, -r, -l, --diff or --summary  may  be  specified  at  a
              time.

       --tempdir dirname
              Write temporary and intermediate data to indicated directory.  Default is "/tmp".

FILES

       /etc/lcovrc
              The system-wide configuration file.

       ~/.lcovrc
              The per-user configuration file.

AUTHOR

       Peter Oberparleiter <Peter.Oberparleiter@de.ibm.com>

       Henry Cox <henry.cox@mediatek.com>
              Filtering, error management, parallel execution sections.

SEE ALSO

       lcovrc(5), genhtml(1), geninfo(1), genpng(1), gendesc(1), gcov(1)

       https://github.com/linux-test-project/lcov