Ubuntu Manpage: genhtml - Generate HTML view from LCOV coverage data files

NAME

       genhtml - Generate HTML view from LCOV coverage data files

SYNOPSIS

       genhtml [-h|--help] [--version]
               [-q|--quiet] [-v|--verbose] [--debug]
               [-s|--show-details]
               [-f|--frames]
               [-b|--baseline-file] baseline-file
               [-o|--output-directory output-directory]
               [--header-title banner]
               [--footer string]
               [-t|--title title]
               [-d|--description-file description-file]
               [-k|--keep-descriptions] [-c|--css-file css-file]
               [-p|--prefix prefix] [--no-prefix]
               [--source-directory dirname]
               [--no-source] [--num-spaces num] [--highlight]
               [--legend] [--html-prolog prolog-file]
               [--html-epilog epilog-file] [--html-extension extension]
               [--html-gzip] [--sort] [--no-sort]
               [--function-coverage] [--no-function-coverage]
               [--branch-coverage] [--no-branch-coverage]
               [--demangle-cpp [param]]
               [--ignore-errors errors]
               [--keep-going] [--config-file config-file] [--rc keyword=value]
               [--precision num] [--missed]
               [--suppress-aliases]
               [--forget-test-names]
               [--dark-mode]
               [--baseline-file baseline-file]
               [--baseline-title title]
               [--baseline-date date]
               [--current-date date]
               [--diff-file diff-file]
               [--annotate-script script]
               [--criteria-script script]
               [--version-script script]
               [--checksum]
               [--new-files-as-baseline]
               [--elide-path-mismatch]
               [--synthesize-missing]
               [--date-bins day[,day,...]]
               [--show-owners [all]]
               [--show-noncode]
               [--show-zero-columns]
               [--show-navigation]
               [--show-proportions]
               [--simplified-colors]
               [--hierarchical] [--flat]
               [--filter filters]
               [--include glob_pattern]
               [--exclude glob_pattern]
               [--erase-functions regexp_pattern]
               [--substitute regexp_pattern]
               [--omit-lines regexp_pattern]
               [--parallel|-j [integer]]
               [--memory integer_num_Mb]
               [--tempdir dirname]
               [--preserve]
               [--save]
               tracefile(s)

DESCRIPTION

genhtml creates an HTML view of coverage data tracefiles generated by the geninfo and lcov
tools. Features include:

• Differential coverage comparison against baseline coverage data

• Annotation of reports with date and owner information ("binning")

The basic concepts of differential coverage and date/owner binning are described in the
paper found at https://arxiv.org/abs/2008.07947

Differential coverage
Differential coverage compares two versions of source code - the baseline and the current
versions - and the coverage results for each to segment the code into categories.

To create a differential coverage report, genhtml requires

1. a baseline-file specified via --baseline-file, and

2. a patch file in unified format specified using --diff-file.

Note that while tracefile may be a list of filenames, baseline-file must be a single
consolidated file.

The difference in coverage between tracefile and baseline-file is classified line-by-line
into categories based on changes in 2 aspects:

1. Test coverage results: a line of code can be tested (1), untested (0), or unused (#).
An unused line is a source code line that has no associated coverage data, for example
due to a disabled #ifdef statement.

2. Source code changes: a line can be unchanged, added (+ =>), or removed (=> -). Note
that the diff-file format used by genhtml reports changes in lines as removal of old
line and addition of new line.

Below are the resulting 12 categories, sorted by priority (assuming that untested code is
more interesting than tested code, and new code is more interesting than old code):

UNC
Uncovered New Code (+ => 0): newly added code is not tested.

LBC
Lost Baseline Coverage (1 => 0): unchanged code is no longer tested.

UIC
Uncovered Included Code (# => 0): previously unused code is untested.

UBC
Uncovered Baseline Code (0 => 0): unchanged code was untested before, is untested
now.

GBC
Gained Baseline Coverage (0 => 1): unchanged code is tested now.

GIC
Gained Included Coverage (# => 1): previously unused code is tested now.

GNC
Gained New Coverage (+ => 1): newly added code is tested.

CBC
Covered Baseline Code (1 => 1): unchanged code was tested before and is still
tested.

EUB
Excluded Uncovered Baseline (0 => #): previously untested code is unused now.

ECB
Excluded Covered Baseline (1 => #): previously tested code is unused now.

DUB
Deleted Uncovered Baseline (0 => -): previously untested code has been deleted.

Note: Because these lines are not represented in the current source version, they
are only represented in the classification summary table.

DCB
Deleted Covered Baseline (1 => -): previously tested code has been deleted.

Note: Because these lines are not represented in the current source version, they
are only represented in the classification summary table.

The differential coverage report colorizes categorized regions in the source code view
using unique colors for each. You can use the --simplified-colors option to instead use
one color for 'covered' code and another for 'uncovered'.

Date and owner binning
Date binning annotates coverage reports with age-of-last-change information to distinguish
recently added or modified code which has not been tested from older, presumed stable code
which is also not tested. Owner binning adds annotation identifying the author of
changes.

Both age and ownership reporting can be used to enhance team efforts to maintain good
coverage discipline by spotlighting coverage shortfalls in recently modified code, even in
the absence of baseline coverage data.

To enable date and owner binning, the --annotate-script option must be used to specify a
script that provides source code line age and ownership information.

For each source line, age is the interval since the most recent modification date and the
owner is the user identity responsible for the most recent change to that line.

Line coverage overall totals and counts for each of the 12 classification categories are
collected for each of the specified age ranges (see the --date-bins option, below).

Script conventions
Some genhtml options expect the name of an external script or tool as argument. These
scripts are then run as part of the associated function. This includes the following
options:

--annotate-script
--criteria-script
--version-script

While each script performs a separate function there are some common aspects in the way
these options are handled:

1. If an option is specified only once, the argument specifies the full command line that
genhtml passes to a shell interpreter to run the script. This includes the script path
followed by optional additional parameters separated by spaces. Care must be taken to
provide proper quoting if script path or any parameter contains spaces or shell special
characters.

2. If an option is specified multiple times, the first invocation specifies the script
path and any further invocation specifies one additional parameter. In this case,
genhtml takes care of quoting of spaces contained in script location and additional
parameters.

3. genhtml passes any additional parameters specified via option arguments between the
script path and the parameters required by the script's function.

Example:

genhtml --annotate-script /bin/script.sh
--annotate-script "full"

results in genhtml executing the following command line:

/bin/script.sh "full" source_file_name

Note that multiple instances of each script may execute simultaneously if the --parallel
option was specified. Therefore each script must either be reentrant or should arrange for
its own synchronization, if necessary.

Additional considerations
If the --criteria-script option is used, genhtml will use the referenced script to
determine whether your coverage criteria have been met - and will return a non-zero status
and print a message if the criteria are not met.

The --version-script option is used to verify that the same/compatible source code
versions are displayed as were used to capture coverage data.

HTML output files are created in the current working directory unless the
--output-directory option is used. If tracefile or baseline-file ends with ".gz", it is
assumed to be GZIP-compressed and the gunzip tool will be used to decompress it
transparently.

Note that all source code files have to be present and readable at the exact file system
location they were compiled, and all path references in the input data ".info" and "diff"
files must match exactly (i.e., exact string match).

Further, the --version-script, --annotate-script, and --criteria-script scripts use the
same path strings. However, see the --substitute option for a mechanism to adjust
extracted paths so they match your source and/or revision control layout.

Use option --diff-file to supply a unified diff file that represents the changes to the
source code files between the version used to compile and capture the baseline trace
files, and the version used to compile and capture the current trace files.

Use option --css-file to modify layout and colors of the generated HTML output. Files are
marked in different colors depending on the associated coverage rate.

By default, the coverage limits for low, medium and high coverage are set to 0-75%, 75-90%
and 90-100% percent respectively. To change these values, use configuration file options.

genhtml_hi_limit and genhtml_med_limit

or type-specific limits:

genhtml_line_hi_limit and genhtml_line_med_limit
genhtml_branch_hi_limit and genhtml_branch_med_limit
genhtml_function_hi_limit and genhtml_function_med_limit

See the lcovrc man page for details.

Also note that when displaying 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.

OPTIONS

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

--version
Print version number, then exit.

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

-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.

--flat
--hierarchical
Use the specified HTML report hierarchy layout.

The default HTML report is 3 levels:

1. top-level: table of all directories,

2. directory: table of source files in a directory, and

3. source file detail: annotated source code.

Option --hierarchical produces a multilevel report which follows the directory
structure of the source code (similar to the file tool in Microsoft Windows).

Option --flat produces a two-level HTML report:

1. top-level: table of all project source files, and

2. source file detail: annotated source code.

Only one of options --flat and --hierarchical can be specified at the same time.

These options can also be persistently set via the lcovrc configuration file using
either:

genhtml_hierarchical = 1

genhtml_flat_view = 1

See the lcovrc man page for details.

-f
--frames
Use HTML frames for source code view.

If enabled, a frameset is created for each source code file, providing an overview
of the source code as a "clickable" image. Note that this option will slow down
output creation noticeably because each source code character has to be inspected
once. Note also that the GD.pm Perl module has to be installed for this option to
work (it may be obtained from http://www.cpan.org).

-s
--show-details
Generate detailed directory view.

When this option is enabled, genhtml generates two versions of each file view. One
containing the standard information plus a link to a "detailed" version. The latter
additionally contains information about which test case covered how many lines of
each source file.

-b baseline-file
--baseline-file baseline-file
Use data in baseline-file as coverage baseline.

The coverage data file specified by baseline-file is read and used as the baseline
for classifying the change in coverage represented by the coverage counts in
tracefile.

In general, you should specify a diff file in unified diff format via --diff-file
when you specify a --baseline-file. Without a diff file, genhtml will assume that
there are no source differences between 'baseline' and 'current'. (For example:
this might be used to find incremental changes caused by the addition of more
testcases, or to compare coverage results between gcc versions, or between gcc and
llvm.)

--baseline-title title
Use title as the descriptive label text for the source of coverage baseline data.

--baseline-date date
Use date as the collection date in text format for the coverage baseline data. If
this argument is not specified, the default is to use the creation time of the
baseline-file as the baseline date.

--current-date date
Use date as the collection date in text format for the coverage baseline data. If
this argument is not specified, the default is to use the creation time of the
current tracefile.

--diff-file diff-file
Use the diff-file as the definition for source file changes between the sample
points for baseline-file and tracefile(s).

A suitable diff-file can be generated using the command:

git diff --relative <SHA_base> <SHA_current>

or using the "p4udiff" or "gitdiff" sample scripts that are provided as part of
this package in the following locations:

/usr/local/share/lcov/support-scripts/p4udiff

and

/usr/local/share/lcov/support-scripts/gitdiff

p4udiff accepts either a changelist ID or the literal string "sandbox"; "sandbox"
indicates that there are modified files which have not been checked in.

These scripts post-process the 'p4' or 'git' output to (optionally) remove files
that are not of interest and to explicitly note files which have not changed. It
is useful to note unchanged files denoted by lines of the form:

diff [optional header strings]
=== file_path

in the p4diff/gitdiff output as this knowledge will help to suppress spurious 'path
mismatch' warnings. See the --elide-path-mismatch option, below.

Note that you must specify --baseline-file when you specify --diff-file. Both are
needed for differential coverage categorization.

Conversely, if you specify a --baseline-file without a --diff-file, then genhtml
will assume that there are no source code changes: source text is identical
between 'baseline' and 'current'.

--annotate-script script
Use script to get source code annotation data.

Use this option to specify an external tool or command line that genhtml can use to
obtain source code annotation data such as age and author of the last change for
each source code line.

This option also instructs genhtml to add a summary table to the HTML report header
that shows counts in the various coverage categories, associated with each date
bin. In addition, each source code line will show age and owner information.

The specified script is expected to obtain age and ownership information for each
source code line from the revision management system and to output this information
in the format described below.

If the annotate script fails and annotation errors are ignored via --ignore-errors,
then genhtml will try to load the source file normally. If the file is not present
or not readable, and the --synthesize-missing flag is specified, then genhtml will
synthesize fake data for the file.

Sample annotation scripts for Perforce ("p4annotate") and git ("gitblame") are
provided as part of this package in the following locations:

/usr/local/share/lcov/support-scripts/p4annotate

and

/usr/local/share/lcov/support-scripts/gitblame

Note that these scripts generate annotations from the file version checked in to
the repository - not the locally modified file in the build directory. If you need
annotations for locally modified files, you can shelve your changes in P4, or check
them in to a local branch in git.

Creating your own script

When creating your own script, please first see Script considerations above for
general calling conventions and script requirements.

script is called by genhtml with the following command line:

script [additional_parameters] source_file_name

where

script
is the script executable

additional_parameters
includes any optional parameters specified (see Script conventions
above)

source_file_name
is the source code file name

The script executable should output a line to the standard output stream in the
following format for each line in file source_file_name:

commit_id|author_id|date|source_code

where

commit_id
is an ID identifying the last change to the line

author_id
identifies the author of the last change

date
is the data of last change in W3CDTF format
(<YYYY>-<MM>-<DD>T<hh>:<mm>:<ss><TZD>)

source_code
is the line's source code

The script should return 0 (zero) if processing was successful and non-zero if it
encountered an error.

--criteria-script script
Use script to test for coverage acceptance criteria.

Use this option to specify an external tool or command line that genhtml can use to
determine if coverage results meet custom acceptance criteria. Criteria checking
results are shown in the standard output log of genhtml. If at least one check
fails, genhtml will exit with a non-zero exit code after completing its processing.

A sample coverage criteria script is provided as part of this package in the
following location:

/usr/local/share/lcov/support-scripts/criteria

The sample script checks that top-level line coverage meets the criteria "UNC + LBC
+ UIC == 0" (added code and newly activated code must be tested, and existing
tested code must not become untested).

As another example, it is possible to create scripts that mimic the lcov
--fail-under-lines feature by checking that the ratio of exercised lines to total
lines ("(GNC + GIC + CBC) / (GNC + GIC + CBC + UNC + UIC + UBC)") is greater than
the threshold - either only at the top level, in every directory, or wherever
desired. Similarly, criteria may include branch and function coverage metrics.

By default the criteria script is called for all source code hierarchy levels,
i.e.: top-level, directory, and file-level. The criteria_callback_levels
configuration file option can be used to limit the hierarchy levels to any
combination of 'top', 'directory', or 'file' levels.

Example:

genhtml --rc criteria_callback_levels=directory,top ...

You can increase the amount of data passed to the criteria script using
configuration file option criteria_callback_data. By default, only total counts
are included. Specifying "date" adds per date-bin counts, "owner" adds per owner-
bin counts.

Example:

genhtml --rc criteria_callback_data=date,owner ...

See the lcovrc man page for more details.

Creating your own script

When creating your own script, please first see Script considerations above for
general calling conventions and script requirements.

script is run with the following command line for each source code file, leaf-
directory, and top-level coverage results:

script [additional_parameters] name type json_data

where

script
is the script executable

additional_parameters
includes any optional parameters specified (see Script conventions
above)

name
is the name of the object for which coverage criteria should be
checked, that is either the source code file name, directory name, or
"top" if the script is called for top-level data

type
is the type of source code object for which coverage criteria should
be checked, that is one of "file", "directory", or "top"

json_data
is a JSON representation of coverage data for the corresponding
source code object

The JSON data format is defined as follows:

{
"<type>": {
"found": <count>,
"hit": <count>,
"<category>": <count>,
...
},
"<bin_type>": {
"<bin_id>" : {
"found": <count>,
"hit": <count>,
"<category>": <count>,
...
},
...
},
...
}

where

type
specifies the type of coverage as one of "line", "function", or
"branch"

bin_type
specifies the type of per-bin coverage as one of "line_age",
"function_age", or "branch_age" for date-bin data, and "line_owners"
or "branch_owners" for owner-bin data

bin_id
specifies the date-bin index for date-bin data, and owner ID for
owner-bin data.

found
defines the number of found lines, functions, or branches

hit
defines the number of hit lines, functions, or branches

category
defines the number of lines, functions, or branches that fall in the
specified category (see Differential coverage above)

Note that data is only reported for non-empty coverage types and bins.

The script should return 0 (zero) if the criteria are met and non-zero otherwise.

If desired, it may print a single line output string which will be appended to the
error log if the return status is non-zero. Additionally, non-empty lines are
appended to the genhtml standard output log.

--version-script script
Use script to get source code file version data.

Use this option to specify an external tool or command line that genhtml can use to
obtain a source code file's version ID when generating HTML or applying source
filters (see --filter option).

A version ID can be a file hash or commit ID from revision control. It is used to
check the version of the source file which is loaded against the version which was
used to generate coverage data (i.e., the file version seen by lcov/geninfo). It is
important that source code versions match - otherwise inconsistent or confusing
results may be produced.

Version mismatches typically happen when the tasks of capture, aggregation, and
report generation are split between multiple jobs - e.g., when the same source code
is used in multiple projects, a unified/global coverage report is required, and the
projects accidentally use different revisions.

Sample scripts for Perforce ("getp4version") and using an md5 hash
("get_signature") are provided as part of this package in the following locations:

/usr/local/share/lcov/support-scripts/getp4version

and

/usr/local/share/lcov/support-scripts/get_signature

Note that you must use the same script/same mechanism to determine the file version
when you extract, merge, and display coverage data - otherwise, you may see
spurious mismatch reports.

Creating your own script

When creating your own script, please first see Script considerations above for
general calling conventions and script requirements.

script is used both to generate and to compare the version ID to enable retaining
history between calls or to do more complex processing to determine equivalence.
It will be called by genhtml with either of the following command lines:

1. Determine source file version ID

script source_file_name

It should write the version ID of source_file_name to stdout and return a 0 exit
status. If the file is not versioned, it should write an empty string and return a
0 exit status.

2. Compare source file version IDs

script --compare source_file_name source_file_id
info_file_id

where

source_file_name
is the source code file name

source_file_id
is the version ID returned by calling "script source_file_name"

info_file_id
is the version ID found in the corresponding .info file

It should return non-zero if the IDs do not match.

--checksum
Specify whether to compare stored tracefile checksum to checksum computed from the
source code.

Checksum verification is disabled by default.

When checksum verification is enabled, a checksum will be computed for each source
code line and compared to the checksum found in the 'current' tracefile. This will
help to prevent attempts to display source code which is not identical to the code
used to generate the coverage data.

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

--new-file-as-baseline
By default, when code is identified on source lines in the 'current' data which
were not identified as code in the 'baseline' data, but the source text has not
changed, their coverpoints are categorized as "included code": GIC or UIC.

However, if the configuration of the coverage job has been recently changed to
instrument additional files, then all un-exercised coverpoints in those files will
fall into the GIC category - which may cause certain coverage criteria checks to
fail.

When this option is specified, genhtml pretends that the baseline data for the file
is the same as the current data - so coverpoints are categorized as CBC or UBC
which do not trigger the coverage criteria check.

Please note that coverpoints in the file are re-categorized only if:

• There is no 'baseline' data for any coverpoint in this file, AND

• The file pre-dates the baseline: the oldest line in the file is older
than the 'baseline' data file (or the value specified by the
--baseline-date option).

--elide-path-mismatch
Differential categorization uses file pathnames to match coverage entries from the
".info" file with file difference entries in the unified-diff-file. If the entries
are not identical, then categorization may be incorrect or strange.

When paths do not match, genhtml will produce "path" error messages to tell you
about the mismatches.

If mismatches occur, the best solution is to fix the incorrect entries in the .info
and/or unified-diff-file files. However, fixing these entries is not possible,
then you can use this option to attempt to automatically work around them.

When this option is specified, genhtml will pretend that the unified-diff-file
entry matches the .info file entries if:

• the same path is found in both the 'baseline' and 'current' .info files,
and

• the basename of the path in the .info file and the path in the
unified-diff-file are the same, and

• there is only one unmatched unified-diff-file entry with that basename.

See the --diff-file discussion above for a discussion of how to avoid spurious
warnings and/or incorrect matches.

--synthesize-missing
Generate (fake) file content if source file does not exist. This option can be
used to work around otherwise fatal annotation errors.

--date-bins day[,day,...]
The --date-bins option is used to specify age boundaries (cutpoints) for
date-binning classification. If not specified, the default is to use 4 age ranges:
less than 7 days, 7 to 30 days, 30 to 180 days, and more than 180 days. This
argument has no effect if there is no source-annotation-script .

--show-owners [all]
If the --show-owners option is used, each coverage report header report contain a
summary table, showing counts in the various coverage categories for everyone who
appears in the revision control annotation as the most recent editor of the
corresponding line. If the optional argument 'all' is not specified, the table
will show only users who are responsible for un-exercised code lines. If the
optional argument is specified, then users responsible for any code lines will
appear. In both cases, users who are responsible for non-code lines (e.g,
comments) are not shown. This option does nothing if --annotate-script is not
used; it needs revision control information provided by calling the script.

Please note: if the all option is not specified, the summary table will contain
"Total" rows for all date/owner bins which are not empty - but there will be no
secondary "File/Directory" entries for elements which have no "missed" coverpoints.

--show-noncode
By default, the source code detail view does not show owner or date annotations in
the far-left column for non-code lines (e.g., comments). If the --show-noncode
option is used, then the source code view will show annotations for both code and
non-code lines. This argument has no effect if there is no
source-annotation-script .

--show-zero-columns
By default, columns whose entries are all zero are removed (not shown) in the
summary table at the top of each HTML page. If the --show-zero-columns option is
used, then those columns will be shown.

When columns are retained, then all the tables have the same width/contain the same
number of columns - which may be a benefit in some situations.

When columns are removed, then the tables are more compact and easier to read.
This is especially true in relatively mature development environments, when there
are very few un-exercised coverpoints in the project.

--show-navigation
By default, the summary table in the source code detail view does not contain
hyperlinks from the number to the first line in the corresponding category ('Hit'
or 'Missed') and from the current location to the next location in the current
category, in non-differential coverage reports. (This is the lcov 'legacy' view
non-differential reports.)

If the --show-navigation option is used, then the source code summary table will be
generated with navigation links. Hyperlinks are always generated for differential
coverage reports.

This feature enables developers to find and understand coverage issues more quickly
than they might otherwise, if they had to rely on scrolling.

--show-proportions
In the 'function coverage detail' table, also show the percentage of lines and
branches within the function which are exercised.

This feature enables developers to focus attention on functions which have the
largest effect on overall code coverage.

This feature is disabled by default. Note that this option requires that you use a
gcc version which is new enough to support function begin/end line reports.

--simplified-colors
By default, each differential category is colorized uniquely in the source code
detail view. With this option, only two colors are used: one for covered code and
another for uncovered code. Note that ECB and EUB code is neither covered nor
uncovered - and so may be difficult to distinguish in the source code view, as they
will be presented in normal background color.

--exclude pattern
pattern is a glob-match pattern of filenames to exclude from the report. Files
which do NOT match will be included. See the lcov man page for details.

--include pattern
pattern is a glob-match pattern of filenames to include in processing. Files which
do not match will be excluded from the report. See the lcov man page for details.

--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.

--substitute regexp_pattern
Apply Perl regexp regexp_pattern to source file names found during processing.
This is useful when some file paths in the baseline or current .info file do not
match your source layout and so the source code is not found. See the lcov man
page for more details.

--omit-lines regexp_pattern
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). See the lcov
man page for details.

--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).

--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 not 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.

--filter filters
Specify a list of coverpoint filters to apply to input data.

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

branch: ignore branch counts for C/C++ source code lines which do not appear to
contain conditionals. These may be generated automatically by the compiler (e.g.,
from C++ exception handling) - and are not interesting to users. This option has
no effect unless --branch-coverage is used.

See also the lcovrc man page - which describes several variables which affect
branch filtering: filter_lookahead and filter_bitwise_conditional.

The most common use for branch filtering is to remove compiler-generated branches
related to C++ exception handlers. See the no_exception_branch' option in the
lcovrc man page for a way to remove all identified exception branches.

brace: ignore line coverage counts on the closing brace of C/C++ code block, if the
line contains only a closing brace and the preceding line has the same count or if
the close brace has a zero count and either the preceding line has a non-zero
count, or the close brace is not the body of a conditional.

These lines seem to appear and disappear in gcov output - and cause differential
coverage to report bogus LBC and/or GIC and/or UIC counts. Bogus LBC or UIC counts
are a problem because an automated regression which uses pass criteria "LBC + UIC +
UNC == 0" will fail.

blank: ignore lines which contain only whitespace (or whitespace + comments) whose
'hit' count is zero. These appear to be a 'gcov' artifact related to compiler-
generated code - such as exception handlers and destructor calls at the end of
scope - and can confuse differential coverage criteria.

range: Ignore line and branch coverpoints on lines which are out-of range/whose
line number is beyond the end of the source file. These appear to be gcov
artifacts caused by a macro instantiation on the last line of the file.

line: alias for "--filter brace,blank".

region: apply LCOV_EXCL_START/LCOV_EXCL_STOP directives found in source text to the
coverpoints found in the current and baseline .info files. This option may be
useful in cases that the source code was not found during 'lcov --capture ...' but
is accessible now.

branch_region: apply LCOV_EXCL_BR_START/LCOV_EXCL_BR_STOP directives found in
source text to the coverpoints found in the current and baseline .info files. This
is similar to the 'region option, above - but applies to branch coverpoints only.

function: combine data for every "unique" function which is defined at the same
file/line. geninfo/gcov seem to have a bug such that they create multiple entries
for the same function. This feature also merges all instances of the same template
function/template method.

trivial: remove trivial functions and associated coverpoints. 'Trivial' functions
are whose body is empty/do not contain any statements. Commonly, these include
compiler-generated methods (e.g., default constructors and assignment operators) as
well as static initialization wrappers, etc.

Note that this filter requires function end line information - and so requires that
you use a gcc veraion which is new enough to support begin/end line reports: gcc/9
or newer, or that you enable lcov/genhtml/geninfo to derive the information:

In the lcovrc man page, see the derive_function_end_line setting as well as the
trivial_function_threshold setting. The former is used to turn end line
calculation on or off, and the latter to change the lookahead used to determine
whether the function body is empty.

-o output-directory
--output-directory output-directory
Create files in output-directory.

Use this option to tell genhtml to write the resulting files to a directory other
than the current one. If output-directory does not exist, it will be created.

It is advisable to use this option since depending on the project size, a lot of
files and subdirectories may be created.

-t title
--title title
Display title in header table of all pages.

title is written to the "Test:"-field in the header table at the top of each
generated HTML page to identify the context in which a particular output was
created. By default, this is the name of the 'current; tracefile.

A common use is to specify a test run name, or a version control system identifier
(perforce changelist or git SHA, for example) that indicates the code level that
was tested.

--header-title BANNER
Display BANNER in header of all pages.

BANNER is written to the header portion of each generated HTML page. By default,
this simply identifies this as an LCOV (differential) coverage report.

A common use is to specify the name of the project or project branch and the
Jenkins build ID.

--footer FOOTER
Display FOOTER in footer of all pages.

FOOTER is written to the footer portion of each generated HTML page. The default
simply identifies the LCOV tool version used to generate the report.

-d description-file
--description-file description-file
Read test case descriptions from description-file.

All test case descriptions found in description-file and referenced in the input
data file are read and written to an extra page which is then incorporated into the
HTML output.

The file format of description-file is:

for each test case:
TN:<testname>
TD:<test description>

Valid test case names can consist of letters, numbers and the underscore character
('_').

-k
--keep-descriptions
Do not remove unused test descriptions.

Keep descriptions found in the description file even if the coverage data indicates
that the associated test case did not cover any lines of code.

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

-c css-file
--css-file css-file
Use external style sheet file css-file.

Using this option, an extra .css file may be specified which will replace the
default one. This may be helpful if the default colors make your eyes want to jump
out of their sockets :)

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

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

For relative paths listed in tracefile, genhtml 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.

-p prefix
--prefix prefix
Remove prefix from all directory names.

Because lists containing long filenames are difficult to read, there is a mechanism
implemented that will automatically try to shorten all directory names on the
overview page beginning with a common prefix. By default, this is done using an
algorithm that tries to find the prefix which, when applied, will minimize the
resulting sum of characters of all directory names.

Use this option to specify the prefix to be removed by yourself.

--no-prefix
Do not remove prefix from directory names.

This switch will completely disable the prefix mechanism described in the previous
section.

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

--no-source
Do not create source code view.

Use this switch if you don't want to get a source code view for each file.

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

--num-spaces spaces
Replace tabs in source view with num spaces.

Default value is 8.

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

--highlight
Highlight lines with converted-only coverage data.

Use this option in conjunction with the --diff option of lcov to highlight those
lines which were only covered in data sets which were converted from previous
source code versions.

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

--legend
Include color legend in HTML output.

Use this option to include a legend explaining the meaning of color coding in the
resulting HTML output.

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

--html-prolog prolog-file
Read customized HTML prolog from prolog-file.

Use this option to replace the default HTML prolog (the initial part of the HTML
source code leading up to and including the <body> tag) with the contents of
prolog-file. Within the prolog text, the following words will be replaced when a
page is generated:

@pagetitle@
The title of the page.

@basedir@
A relative path leading to the base directory (e.g., for locating css-files).

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

--html-epilog epilog-file
Read customized HTML epilog from epilog-file.

Use this option to replace the default HTML epilog (the final part of the HTML
source including </body>) with the contents of epilog-file.

Within the epilog text, the following words will be replaced when a page is
generated:

@basedir@
A relative path leading to the base directory (e.g., for locating css-files).

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

--html-extension extension
Use customized filename extension for generated HTML pages.

This option is useful in situations where different filename extensions are
required to render the resulting pages correctly (e.g., php). Note that a '.' will
be inserted between the filename and the extension specified by this option.

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

--html-gzip
Compress all generated html files with gzip and add a .htaccess file specifying
gzip-encoding in the root output directory.

Use this option if you want to save space on your webserver. Requires a webserver
with .htaccess support and a browser with support for gzip compressed html.

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

--sort
--no-sort
Specify whether to include sorted views of file and directory overviews.

Use --sort to include sorted views or --no-sort to not include them. Sorted views
are enabled by default.

When sorted views are enabled, each overview page will contain links to views of
that page sorted by coverage rate.

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

--function-coverage
--no-function-coverage
Specify whether to display function coverage summaries in HTML output.

Use --function-coverage to enable function coverage summaries or
--no-function-coverage to disable it. Function coverage summaries are enabled by
default.

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

When function coverage summaries are enabled, each overview page will contain the
number of functions found and hit per file or directory, together with the
resulting coverage rate. In addition, each source code view will contain a link to
a page which lists all functions found in that file plus the respective call count
for those functions. The function coverage page groups the data for every alias of
each function, sorted by name or execution count. The representative name of the
group of functions is the shorted (i.e., containing the fewest characters).

If using differential coverage and a sufficiently recent gcc version which report
both begin and end line of functions (gcc/9 and newer), functions are considered
'new' if any of their source lines have changed. With older gcc versions,
functions are considered 'new' if the function signature has changed or if the
entire function is new.

--branch-coverage
--no-branch-coverage
Specify whether to display branch coverage data in HTML output.

Use --branch-coverage to enable branch coverage display or --no-branch-coverage to
disable it. Branch coverage data display is disabled by default.

When branch coverage display is enabled, each overview page will contain the number
of branches found and hit per file or directory, together with the resulting
coverage rate. In addition, each source code view will contain an extra column
which lists all branches of a line with indications of whether the branch was taken
or not. Branches are shown in the following format:

' + ': Branch was taken at least once
' - ': Branch was not taken
' # ': The basic block containing the branch was never executed

Note that it might not always be possible to relate branches to the corresponding
source code statements: during compilation, GCC might shuffle branches around or
eliminate some of them to generate better code.

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

--demangle-cpp [param]
Specify whether to demangle C++ function names.

Use this option if you want to convert C++ internal function names to human
readable format for display on the HTML function overview page.

If called with no parameters, genhtml will use c++filt for demangling. This
requires that the c++filt tool is installed (see c++filt(1)).

If param is specified, it is treated as th tool to call to demangle source code.
The --demangle-cpp option can be used multiple times to specify the demangling tool
and a set of command line options that are passed to the tool - similar to how the
gcc -Xlinker paramter works. In that case, you callback will be executed as: |
demangle_param0 demangle_param1 ... Note that the demangle tool is called as a
pipe and is expected to read from stdin and write to stdout.

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

Use this option to specify a list of error classes after which genhtml should
continue processing with a warning message instead of aborting. To suppress the
warning message, specify the error class twice.

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

annotate: --annotate-script returned non-zero exit status - likely a file path or
related error. HTML source code display will not be correct and ownership/date
information may be missing.

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

callback: Annotate, version, or criteria script error.

category: Line number categorizations are incorrect in the .info file, so branch
coverage line number turns out to not be an executable source line.

count: An excessive number of messages of some class has 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.

corrupt: Corrupt/unreadable coverage data file found.

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 patch file specified by the --diff-file argument does not contain any
differences. This may be OK if there were no source code changes between
'baseline' and 'current' (e.g., the only change was to modify a Makefile) - or may
indicate an unsupported file format.

format: Unexpected syntax found in .info file.

inconsistent: Files have been moved or repository history presented by --diff-file
data is not consistent with coverage data; for example, an 'inserted' line has
baseline coverage data. These issues are likely to be caused by inconsistent
handling in the 'diff' and 'annotate' scripts.

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:...).

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 - 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 --parallel flag and try again.

path: File name found in --diff-file file but does not appear in either baseline or
current trace data. These may be mapping issues - different pathname in the
tracefile vs. the diff file.

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

unmapped: Coverage data for a particular line cannot be found, possibly because the
source code was not found, or because the line number mapping in the .info file is
wrong.

This can happen if the source file used in HTML generation is not the same as the
file used to generate the coverage data - for example, lines have been added or
removed.

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/substitute/omit pattern did not match any file
pathnames.

version: --version-script comparison returned non-zero mismatch indication. It
likely that the version of the file which was used in coverage data extraction is
different than the source version which was found. File annotations may be
incorrect.

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.

--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 lcovrc option. See the
lcovrc man page for more details.

--config-file config-file
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 genhtml
with different configuration file options in parallel.

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

--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 lcovrc(5) for a list of available keywords and their meaning.

--precision num
Show coverage rates with num number of digits after the decimal point.

Default value is 1.

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

--suppress-aliases
Suppress list of aliases in function detail table.

Functions whose file/line is the same are considered to be aliases; genthml uses
the shortest name in the list of aliases (fewest characters) as the leader.

The number of aliases can be large, for example due to instantiated templates -
which can make function coverage results difficult to read. This option removes
the list of aliases, making it easier to focus on the overall function coverage
number, which is likely more interesting.

Note that this option has an effect only when --filter function is applied.

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

--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.

--missed
Show counts of missed lines, functions, or branches.

Use this option to change overview pages to show the count of lines, functions, or
branches that were not hit. These counts are represented by negative numbers.

When specified together with --sort, file and directory views will be sorted by
missed counts.

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

--dark-mode
Use a light-display-on-dark-background color scheme rather than the default
dark-display-on-light-background.

The idea is to reduce eye strain due to viewing dark text on a bright screen -
particularly at night.

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

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

--save
Copy unified-diff-file, baseline_trace_file, and tracefile(s) to output-directory.

Keeping copies of the input data files may help to debug any issues or to
regenerate report files later.

FILES

       /etc/lcovrc
              The system-wide configuration file.

       ~/.lcovrc
              The per-user configuration file.

       /usr/local/share/lcov/support-scripts/p4udiff
              Sample  script  for  use  with  --diff-file  that  creates  a unified diff file via
              Perforce.

       /usr/local/share/lcov/support-scripts/gitdiff
              Sample script for use with --diff-file that creates a unified diff file via git.

       /usr/local/share/lcov/support-scripts/p4annotate
              Sample script for use with --annotate-script  that  provides  annotation  data  via
              Perforce.

       /usr/local/share/lcov/support-scripts/gitblame
              Sample script for use with --annotate-script that provides annotation data via git.

       /usr/local/share/lcov/support-scripts/criteria
              Sample script for use with --criteria-script that implements a check for "UNC + LBC
              + UIC == 0".

       /usr/local/share/lcov/support-scripts/getp4version
              Sample script for use with --version-script that obtains version IDs via Perforce.

       /usr/local/share/lcov/support-scripts/get_signature
              Sample script for use with --version-script that uses md5hash as version IDs.

AUTHORS

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

       Henry Cox <henry.cox@mediatek.com>
              Differential coverage and date/owner binning, filtering, error management, parallel
              execution sections,

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

FILES

AUTHORS

SEE ALSO