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

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.

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

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

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

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

See man geninfo(1)) for details.

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

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

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.

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

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

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

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.

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

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

Valid modes are:

libtool

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.

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.

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

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.

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.

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.

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

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".

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

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

External 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.

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

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:

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.

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.

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.

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

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

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

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

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.

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.

See the geninfo man page for more details.

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.

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:

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

branch:

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

callback:

Version script error.

child:

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

corrupt:

corrupt/unreadable file found.

count:

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

deprecated:

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

empty:

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

excessive:

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

format:

unexpected syntax found in .info file.

gcov:

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

graph:

the graph file could not be found or is corrupted.

internal:

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

mismatch:

Inconsistent entries found in trace file:

missing:

File does not exist or is not readable.

negative:

negative 'hit' count found.

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

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

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

package:

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

parallel:

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

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

parent:

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

range:

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

source:

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

unsupported:

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

unused:

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

usage:

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

utility:

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

version:

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

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

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

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

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.

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

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.

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".

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

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.

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

Currently - parallelism is used with the --add-tracefile and --capture options.

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

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

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

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.

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

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.

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 ("_").

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:

On the build machine:

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.

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.