Provided by: lcov_2.0-4ubuntu2_all 
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]
[-i|--initial]
[--gcov-tool tool]
[--branch-coverage]
[--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]
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]
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 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 help message and exit
lcov --summary
Common lcov options - supported by all the above use cases:
lcov ...
[--keep-going]
[--filter type]
[-q|--quiet]
[-v|--verbose]
[--debug]
[(--parallel|-j) [integer]]
[--memory integer_num_Mb]
[--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.
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 lcovrc(5)).
--build-directory build_directory
Searchfor.gcnodatafilesfrombuild_directoryratherthan adjacent to the corresponding .gcda file.
See man geninfo(1)) for details.
-c
--capture
Capture 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.
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 lcov_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 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 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.
--substitute regexp_pattern
Apply Perl regexp 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,
or when the paths found in the extracted .info file does not match your source code layout.
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 perlre(1)) , you can
instruct geninfo to remove or change parts of the incorrect source path.
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 "$".
--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.
-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.
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 the lcovrc man page.
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.
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.
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.
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.
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 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 the lcovrc man
page 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.
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
-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).
Currently - parallelism is used with the --add-tracefile and --capture options.
--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.
--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.
-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
2024-03-25 LCOV 2.0 lcov(1)