geninfo.1

\" Define path to scripts
.ds scriptdir bin

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.ds lcovurl https://github.com/linux\-test\-project/lcov

.TH geninfo 1 "LCOV 2.0" 2023\-05\-17 "User Manuals"
.SH NAME
geninfo \- Generate tracefiles from GCOV coverage data files
.SH SYNOPSIS
.B geninfo
.RB [ \-h | \-\-help ]
.RB [ \-\-version ]
.RB [ \-q | \-\-quiet ]
.RB [ \-v | \-\-verbose ]
.RB [ \-\-debug ]
.br
.RS 8
.RB [ \-\-comment
.IR comment-string ]
.br
.RB [ \-i | \-\-initial ]
.RB [ \-t | \-\-test\-name
.IR test\-name ]
.br
.RB [ \-o | \-\-output\-filename
.IR filename ]
.RB [ \-f | \-\-follow ]
.br
.RB [ \-b | \-\-base\-directory
.IR directory ]
.br
.RB [ \-\-build\-directory
.IR directory ]
.br
.RB [ \-\-branch\-coverage ]
.br
.RB [ \-\-checksum ]
.RB [ \-\-no\-checksum ]
.br
.RB [ \-\-compat\-libtool ]
.RB [ \-\-no\-compat\-libtool ]
.br
.RB [ \-\-gcov\-tool
.IR tool  ]
.br
.RB [ \-\-parallel | -j
.IR [integer] ]
.br
.RB [ \-\-memory
.IR integer_num_Mb ]
.br
.RB [ \-\-ignore\-errors
.IR errors ]
.br
.RB [ \-\-keep\-going ]
.br
.RB [ \-\-preserve ]
.br
.RB [ \-\-filter
.IR type  ]
.br
.RB [ \-\-demangle\-cpp [param]]
.br
.RB [ \-\-no\-recursion ]
.RB [ \-\-external ]
.RB [ \-\-no\-external ]
.br
.RB [ \-\-config\-file
.IR config\-file ]
.RB [ \-\-no\-markers ]
.br
.RB [ \-\-derive\-func\-data ]
.RB [ \-\-compat
.IR  mode =on|off|auto]
.br
.RB [ \-\-rc
.IR keyword = value ]
.br
.RB [ \-\-include
.IR glob_pattern ]
.br
.RB [ \-\-exclude
.IR glob_pattern ]
.br
.RB [ \-\-erase\-functions
.IR regexp_pattern ]
.br
.RB [ \-\-substitute
.IR regexp_pattern ]
.br
.RB [ \-\-omit\-lines
.IR regexp_pattern ]
.br
.RB [ \-\-forget\-test\-names ]
.br
.RB [ \-\-version\-script
.IR script_file  ]
.br
.RB [ \-\-tempdir
.IR dirname  ]
.br
.IR directory
.RE

.SH DESCRIPTION

Use
.B geninfo
to create LCOV tracefiles from GCC and LLVM/Clang coverage data files (see
.B --gcov-tool
for considerations when working with LLVM). You can use
.B genhtml
to create an HTML report from a tracefile.
.br

Note that
.B geninfo
is called by
.BR "lcov --capture" ,
so there is typically no need to call it directly.
.br

Unless the
.B --output-filename
option is specified
.B geninfo
writes its output to one file with .info filename extension per input file.
.br

Note also that the current user needs write access to both
.I directory
as well as to the original source code location. This is necessary because some temporary files have to be created there during the conversion process.
.br

By default,
.B geninfo
collects line and function coverage data.
Branch data is not collected; you can use the
.B --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 the
.B lcovrc
man page for details.


.SS "File types"

A
.B tracefile
is a coverage data file in the format used by all LCOV tools such as
.BR geninfo ", " lcov ", and " genhtml .
By convention, tracefiles have a .info filename extension. See "Tracefile format" below for a description of the file format.
.br

A
.B .gcda file
is a compiler-specific file containing run-time coverage data. It is created and updated when a program compiled with GCC/LLVM's
.B --coverage
option is run to completion.
.B geninfo
reads .gcda files in its default mode of operation. Note: earlier compiler versions used the .da filename extension for this file type.
.br

A
.B .gcno file
is a compiler-specific file containing static, compile-time coverage data. It is created when source code is compiled with GCC/LLVM's
.B --coverage
option.
.B geninfo
reads .gcno files when option
.B --initial
is specified. Note: earlier compiler versions used .bb and .bbg filename extensions for this file type.
.br

A
.B .gcov file
is a textual or JSON representation of the data found in .gcda and .gcno files. It is created by the
.BR gcov
tools that is part of GCC (see
.B --gcov-tool
for LLVM considerations).
There are multiple gcov file format versions, including textual, intermediate, and JSON format.
.B geninfo
internally uses
.B gcov
to extract coverage data from .gcda and .gcno files using the best supported gcov file format.
.br

See the
.B gcov
man page for more information on .gcda, .gcno and .gcov output formats.
.br

.SS "Exclusion markers"

To exclude specific lines of code from a tracefile, you can add exclusion
markers to the source code. Additionally you can exclude specific branches from
branch coverage without excluding the involved lines from line and function
coverage. Exclusion markers are keywords which can for example be added in the
form of a comment.
See
.BR lcovrc (5)
how to override some of them.

The following markers are recognized by geninfo:

.B LCOV_EXCL_LINE
.br
.RS
Lines containing this marker will be excluded.
.br
.RE

.B LCOV_EXCL_START
.br
.RS
Marks the beginning of an excluded section. The current line is part of this
section.
.br
.RE

.B LCOV_EXCL_STOP
.br
.RS
Marks the end of an excluded section. The current line not part of this
section.
.br
.RE

.B LCOV_EXCL_BR_LINE
.br
.RS
Lines containing this marker will be excluded from branch coverage.
.br
.RE

.B LCOV_EXCL_BR_START
.br
.RS
Marks the beginning of a section which is excluded from branch coverage. The
current line is part of this section.
.br
.RE

.B LCOV_EXCL_BR_STOP
.br
.RS
Marks the end of a section which is excluded from branch coverage. The current
line not part of this section.
.br
.RE

.B LCOV_EXCL_EXCEPTION_BR_LINE
.br
.RS
Lines containing this marker will be excluded from exception branch coverage:
Exception branches will be ignored, but non-exception branches will not be
affected.
.br
.RE

.B LCOV_EXCL_EXCEPTION_BR_START
.br
.RS
Marks the beginning of a section which is excluded from exception branch
coverage. The current line is part of this section.
.br
.RE

.B LCOV_EXCL_EXCEPTION_BR_STOP
.br
.RS
Marks the end of a section which is excluded from exception branch coverage.
The current line not part of this section
.br
.RE

.SH OPTIONS

.B \-b
.I directory
.br
.B \-\-base\-directory
.I directory
.br
.RS
.RI "Use " directory
as base directory for relative paths.

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

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

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

This option is required when using geninfo 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
.B geninfo_auto_base=1
(see
.BR lcovrc (5)).
.RE

.B \-\-build\-directory
.I build_dir
.br
.RS
Search for .gcno data files from
.I build_dir
rather finding them only adjacent to the corresponding .o and/or .gcda file.

By default, geninfo expects to find the .gcno and .gcda files (compile-
and run-time data, respectively) in the same directory.
.br

When this option is used:
.br

.RS
geninfo path1 \-\-build\-directory path2 ...
.RE
.br

then geninfo will look for .gcno file
.br

.RS
path2/relative/path/to/da_base.gcno
.RE
.br

when it finds .gcda file
.br

.RS
path1/relative/path/to/da_base.gcda.
.RE

Use this option when you have used the
.I GCOV_PREFIX
environment variable to direct the gcc or llvm runtime environment to write
coverage data files to somewhere other than the directory where the code
was originally compiled.
See
.BR gcc (1)
and/or search for
.I GCOV_PREFIX
and
.I GCOV_PREFIX_STRIP.

This option can be used several times to specify multiple alternate directories to look for .gcno files.  This may be useful if your application uses code which is compiled in many separate locations - for example, common libraries that are shared between teams.

.RE

.B \-\-branch\-coverage
.br
.RS
Collect 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.

.RE

.B \-\-checksum
.br
.B \-\-no\-checksum
.br
.RS
Specify whether to generate checksum data when writing tracefiles.

Use
.B \-\-checksum
to enable checksum generation or
.B \-\-no\-checksum
to disable it. Checksum generation is
.B 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
.B \-\-version\-script
option - which does something similar, but at the 'whole file' level.

.RE

.B \-\-compat
.IR mode = value [, mode = value ,...]
.br
.RS
Set compatibility mode.

Use
.B \-\-compat
to specify that geninfo 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
.I values
are:

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

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

Valid
.I modes
are:

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

The default value for this setting is 'on'.

.RE
.B hammer
.RS
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'.

.RE
.B split_crc
.RS
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 geninfo 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'
.RE

.RE

.B \-\-compat\-libtool
.br
.B \-\-no\-compat\-libtool
.br
.RS
Specify whether to enable libtool compatibility mode.

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

When libtool compatibility mode is enabled, geninfo will assume that the source
code relating to a .gcda 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.
.RE

.B \-\-config\-file
.I config\-file
.br
.RS
Specify a configuration file to use.
See the lcovrc man page 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
.B geninfo
with different configuration file options in parallel.

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

.RE

.B \-\-derive\-func\-data
.br
.RS
Calculate function coverage data from line coverage data.

Use this option to collect function coverage data, even if the version of the
gcov tool installed on the test system does not provide this data. lcov will
instead derive function coverage data from line coverage data and
information about which lines belong to a function.
.RE

.B \-\-external
.br
.B \-\-no\-external
.br
.RS
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
.I directory
or
.BR \-\-base\-directory .
Use
.B \-\-external
to include external source files while capturing coverage data or
.B \-\-no\-external
to ignore this data.

Data for external source files is
.B included
by default.
.RE

.B \-f
.br
.B \-\-follow
.RS
Follow links when searching .gcda files.
.RE

.B \-\-gcov\-tool
.I tool
.br
.RS
Specify the location of the gcov tool.

If the
.B \-\-gcov\-tool
option is used multiple times, then the arguments are concatenated when the callback
is executed - similar to how the gcc
.B \-Xlinker
parameter works.  This provides a possibly easier way to pass arguments to
your tool, without requiring a wrapper script.
In that case, your callback will be executed as:
.I tool\-0 'tool\-1; ... 'filename'.
Note that the second and subsequent arguments are quoted when passed to
the shell, in order to handle parameters which contain spaces.

A common use for this option is to enable LLVM:
.br

.RS
.BR "geninfo \-\-gcov-tool " "llvm-cov " "\-\-gcov-tool " "gcov ..."
.RE
.br

Note: 'llvm-cov gcov da_file_name' will generate output in gcov-compatible format as required by lcov.

If not specified, 'gcov' is used by default.

.RE

.B \-h
.br
.B \-\-help
.RS
Print a short help text, then exit.
.RE

.B \-\-include
.I pattern
.br
.RS
Include source files matching
.IR 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
.B \-\-include
command line switches. The
.I 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).

See the lcov man page for details

.RE

.B \-\-exclude
.I pattern
.br
.RS
Exclude source files matching
.IR pattern .

Use this switch if you want to exclude coverage data from a  particular set
of source files matching any of the given patterns. Multiple patterns can be
specified by using multiple
.B \-\-exclude
command line switches. The
.I 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
.B absolute
path of each source file.

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

See the lcov man page for details.

.RE

.B \-\-erase\-functions
.I regexp
.br
.RS
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
.BI derive_function_end_line
discussion in the
.B lcovrc
man page.


.RE

.B \-\-substitute
.I regexp_pattern
.br
.RS
Apply Perl regexp
.IR regexp_pattern
to source file names found during processing.  This is useful when the path name reported by gcov does not match your source layout and the file is not found. See the lcov man page for more details.

.RE

.B \-\-omit\-lines
.I regexp
.br
.RS
Exclude coverage data from lines whose content matches
.IR 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).
See the lcov man page for details.

.RE

.B \-\-forget\-test\-names
.br
.RS
If non\-zero, ignore testcase names in tracefile -
.I 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
.IR forget_testcase_names .
.RE

.B \-\-ignore\-errors
.I errors
.br
.RS
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
.B geninfo
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:
.br
.RS
geninfo ... \-\-ignore\-errors unused,unused
.RE

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

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

.B callback:
Version script error.
.br

.B corrupt:
corrupt/unreadable file found.

.B 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 the lcovrc man page.

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

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

.B format:
unexpected syntax found in .info file.

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

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

.B mismatch:
Inconsistent entries found in trace file:
.IP \(bu 3
branch expression (3rd field in the .info file 'BRDA' entry) of merge data does not match, or
.br

.PP
.IP \(bu 3
function execution count (FNDA:...) but no function declaration (FN:...).
.br
.PP

.B negative:
negative 'hit' count found.
.br

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

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

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

.B 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.

.B parallel:
various types of errors related to parallelism - e.g., child process died due to some error.   If you see an error related to parallel execution, it may be a good idea to remove the
.B \-\-parallel
flag and try again.

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

.B 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.

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

.B 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.

.br
Also see man lcovrc 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.

.RE
.BI "\-\-keep\-going "
.RS
Do not stop if error occurs: attempt to generate a result, however flawed.

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

.RE

.BI "\-\-preserve "
.RS
Preserve intermediate data files (e.g., for debugging).

By default, intermediate files are deleted.

.RE
.BI "\-\-filter "
.I filters
.RS
Specify a list of coverpoint filters to apply to input data.
See the genhtml man page for details.

.RE
.BI "\-\-demangle\-cpp " [param]
.RS
Demangle C++ method and function names in captured output.
See the genhtml man page for details.

.RE
.B \-i
.br
.B \-\-initial
.RS
Capture initial zero coverage data.

Run geninfo with 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 and function.
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 object code files were loaded during the test.

Note: currently, the
.B \-\-initial
option does not generate branch coverage information.
.RE

.B \-\-no\-markers
.br
.RS
Use this option if you want to get coverage data without regard to exclusion
markers in the source code file.
.RE

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

.BI "\-o " output\-filename
.br
.BI "\-\-output\-filename " output\-filename
.RS
Write all data to
.IR output\-filename .

If you want to have all data written to a single file (for easier
handling), use this option to specify the respective filename. By default,
one tracefile will be created for each processed .gcda file.
.RE

.RE
.B \-\-version\-script
.I script
.br
.RS
Use
.I script
to get a source file's version ID from revision control when
extracting data. The ID is used for error checking when merging .info files.
.br

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

.B \-v
.br
.B \-\-verbose
.RS
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
.B \-\-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.

.RE
.B \-q
.br
.B \-\-quiet
.RS
Decrement informational message verbosity.

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

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

.RE
.B \-\-comment comment_string
.RS
Append
.I 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 can be useful to document the conditions under which the trace file was
generated:  host, date, environment,
.I etc.


.RE

.BI "\-\-parallel "
.I [ integer ]
.br
.BI "\-j "
.I [ integer ]
.RS
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).

See the
.I geninfo_chunk_size
and
.I geninfo_interval_update
enttries in the
.B lcovrc
man page for a description of some options which may aid in paramter tuning and performance optiminzation.

.RE
.BI "\-\-memory "
.I integer
.RS
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.

.RE

.B \-\-rc
.IR keyword = value
.br
.RS
Override a configuration directive.

Use this option to specify a
.IR 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
.BR lcovrc (5)
for a list of available keywords and their meaning.
.RE

.BI "\-t " testname
.br
.BI "\-\-test\-name " testname
.RS
Use test case name
.I testname
for resulting data. Valid test case names can consist of letters, decimal
digits and the underscore character ('_').

This proves useful when data from several test cases is merged (i.e. by
simply concatenating the respective tracefiles) in which case a test
name can be used to differentiate between data from each test case.
.RE

.B \-\-version
.RS
Print version number, then exit.
.RE

.B \-\-tempdir
.I dirname
.br
.RS
Write temporary and intermediate data to indicated directory.  Default is "/tmp".
.RE


.SH "TRACEFILE FORMAT"

Following is a quick description of the tracefile format as used by
.BR genhtml ", " geninfo " and " lcov .

A tracefile is made up of several human\-readable lines of text,
divided into sections.  If the
.BI "--\-comment\ comment_string"
option is supplied, then

.RS
 #comment_string
.RE
will appeaare at the top of the tracefile.  There is no space before or after the
.I #
character.


If available, a tracefile begins with the
.I testname
which is stored in the following format:

.RS
TN:<test name>
.RE

For each source file referenced in the .gcda file, there is a section containing
filename and coverage data:

.RS
SF:<path to the source file>
.RE

An optional source code version ID follows:
.br

.RS
VER:<version ID>
.RE

If present, the version ID is compared before file entries are merged (see
.B "lcov \-\-add\-tracefile"
), and before the 'source detail' view is generated by genhtml.
See the
.BI "\-\-version\-script " callback_script
documentation and the sample usage in the lcov regression test examples.

Following is a list of line numbers for each function name found in the
source file:

.RS
FN:<line number of function start>,[<line number of function end>,]<function name>
.RE

The 'end' line number is optional, and is generated only if the compiler/toolchain
version is recent enough to generate the data (e.g., gcc 9 or newer).
This data is used to support the
.B \-\-erase\-functions
and
.B \-\-show\-proportions
options.  If the function end line data is not available, then these features will not work.

Next, there is a list of execution counts for each instrumented function:

.RS
FNDA:<execution count>,<function name>
.RE

This list is followed by two lines containing the number of functions found
and hit:

.RS
FNF:<number of functions found>
.br
FNH:<number of function hit>
.RE

Branch coverage information is stored which one line per branch:

.RS
BRDA:<line_number>,[<exception>]<block>,<branch>,<taken>
.RE

.I <line_number>
is the line number where the branch is found - and is expected to to be a non-zero integer.
.br
.I <block>
and
.I <branch>
serve to uniquely define a particular edge in the expression tree of a particular conditional found on the associated line.
.br
Within a particular line,
.I <block>
is an integer numbered from zero with no gaps. For some languages and some coding styles, there will only be one block (index value zero) on any particular line.
.br
.I <branch>
is a string which serves to uniquely identify a particular edge.  For some languages and tools - e.g., C/C++ code compiled with gcc or llvm -
.I <branch>
is an ordered integer index related to expression tree traversal order of the associated conditional.  For others, it may be a meaningful string - see below.
.I <branch>
appears in the 'tooltip' popup of the asognciated branch in the
.B genhtml
output - so human-readable values are helpful to users who are trying to understand coveage results.
.br
.I <taken>
is either '-' if the corresponding expression was never evaluated (e.g., the basic block containing the branch was never executed) or
a number indicating how often that branch was taken.
.br
.I <exception>
is 'e' (single character) if this is a branch related to exception handling - and is not present if the branch is not related to exceptions.
Exception branch identification requires compiler support; note that gcc versions older than 9 do not differentiate exception branches.  Geninfo will be able to identify exception branches only if your toolchain version is new enough to support the feature.

The following is an example branch records whose
.I <branch>
expression values are human-readable strings.

.RS
  BRDA:10,0,enable,1
.br
  BRDA:10,0,!enable,0
.RE
In this case, the corresponding code from line 10 is very likely similar to:
.br
.RS
   if (enable) {
.br
     ...
.br
   }
.br
.RE
such that associated testcase entered the block ('enable' evaulated to 'true').

Arbitrarily complicated branch expressions are supported - including branch expressions which contain commas (e.g., in an expression containing a function call).

Note that particular tools may or may not suppress expressions which are statically true or statically false - e.g., expressions using template parameters.
This makes it potentially complicated to compare coverage data generated by two different tools.


Branch coverage summaries are stored in two lines:

.RS
BRF:<number of branches found>
.br
BRH:<number of branches hit>
.RE

Then there is a list of execution counts for each instrumented line
(i.e. a line which resulted in executable code):

.RS
DA:<line number>,<execution count>[,<checksum>]
.RE

Note that there may be an optional checksum present for each instrumented
line. The current
.B geninfo
implementation uses an MD5 hash as checksumming algorithm.

At the end of a section, there is a summary about how many lines
were found and how many were actually instrumented:

.RS
LH:<number of lines with a non\-zero execution count>
.br
LF:<number of instrumented lines>
.RE

Each sections ends with:

.RS
end_of_record
.RE

In addition to the main source code file there are sections for all
#included files which also contain executable code.

Note that the absolute path of a source file is generated by interpreting
the contents of the respective .gcno file (see
.BR "gcov " (1)
for more information on this file type). Relative filenames are prefixed
with the directory in which the .gcno file is found.

Note also that symbolic links to the .gcno file will be resolved so that the
actual file path is used instead of the path to a link. This approach is
necessary for the mechanism to work with the /proc/gcov files.


.SH FILES

.I /etc/lcovrc
.RS
The system\-wide configuration file.
.RE

.I ~/.lcovrc
.RS
The per\-user configuration file.
.RE

.I \*[scriptdir]/getp4version
.RS
Sample script for use with
.B --version-script
that obtains version IDs via Perforce.
.br
.RE

.I \*[scriptdir]/get_signature
.RS
Sample script for use with
.B --version-script
that uses md5hash as version IDs.
.br
.RE


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

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

.SH SEE ALSO
.BR lcov (1),
.BR lcovrc (5),
.BR genhtml (1),
.BR genpng (1),
.BR gendesc (1),
.BR gcov (1)
.br

.I \*[lcovurl]
.br