@c This file is generated automatically by convert.pl from gtags/manual.in.
@unnumberedsubsec NAME
gtags - create tag files for global
@unnumberedsubsec SYNOPSIS
@quotation
gtags [-ciIOqvw][-C dir][-d tag-file][-f file][dbpath]@*
@end quotation
@unnumberedsubsec DESCRIPTION
Gtags is used to create tag files for global(1).

Gtags recursively collects source files under the current directory,
picks up symbols and writes the cross-reference data into the tag files
(@file{GTAGS}, @file{GRTAGS} and @file{GPATH}).

By default, gtags picks up
C, Yacc, assembly language, Java, C++ and PHP source files.
Files whose names end in @file{.c}, @file{.h} are assumed to be C source files.
Files whose names end in @file{.y} are assumed to be Yacc source files.
Files whose names end in @file{.s}, @file{.S} are assumed to be assembly language source files.
Files whose names end in @file{.java} are assumed to be Java source files.
Files whose names end in @file{.c++}, @file{.cc}, @file{.hh}, @file{.cpp}, @file{.cxx}, @file{.hxx}, @file{.hpp}, @file{.C}, @file{.H} are assumed to be C++ source files.
Files whose names end in @file{.php}, @file{.php3}, @file{.phtml} are assumed to be PHP source files.
Other files are assumed to be text files. Gtags does not treat binary files.

If @file{gtags.files} exists in the current directory
or a file is specified by the @samp{-f} option,
target files are limited by it. Lines starting with @samp{. } are comments.
@unnumberedsubsec OPTIONS
The following options are available:

@table @asis
@item @samp{--accept-dotfiles}
Accept files and directories whose names begin with a dot.
By default, gtags ignores them.
@item @samp{-c}, @samp{--compact}
Make @file{GTAGS} in compact format.
This option does not influence @file{GRTAGS},
because that is always made in compact format.
@item @samp{-C}, @samp{--directory} dir
Change the directory before doing all the work including parameter analysis.
This option is ignored in @var{GTAGS_OPTIONS}.
Please specify it on the command line directly.
@item @samp{--config}[=name]
Print the value of config variable name.
If name is not specified then print all names and values.
Additionally, you can refer to the directory name where the system
is installed as read only variables:
@var{bindir}, @var{libdir}, @var{datadir}, @var{localstatedir} and @var{sysconfdir}.
@item @samp{-d}, @samp{--dump} tag-file
Dump a tag file as text to the standard output.
Output format is 'key<tab>data'. This is for debugging.
@item @samp{--explain}
Explain handling files.
@item @samp{-f}, @samp{--file} file
Give a list of candidates of target files.
Files which are not on the list are ignored.
The argument file can be set to @samp{-} to accept a list of
files from the standard input.
File names must be separated by newline.
To make the list you may use find(1), which has rich options
for selecting files.
@item @samp{--gtagsconf} file
Set environment variable @var{GTAGSCONF} to file.
@item @samp{--gtagslabel} label
Set environment variable @var{GTAGSLABEL} to label.
@item @samp{--help}
Print a usage message.
@item @samp{-I}, @samp{--idutils}
In addition to tag files, make ID database for idutils(1).
@item @samp{-i}, @samp{--incremental}
Update tag files incrementally.
It's better to use global(1) with the @samp{-u} command.
@item @samp{-O}, @samp{--objdir}
Use BSD-style obj directory as the location of tag files.
If @var{GTAGSOBJDIRPREFIX} is set and @file{$GTAGSOBJDIRPREFIX} directory exists,
gtags creates @file{$GTAGSOBJDIRPREFIX/<current directory>} directory
and makes tag files in it.
Though you can use @var{MAKEOBJDIRPREFIX} instead of @var{GTAGSOBJDIRPREFIX},
it is deprecated.
If dbpath is specified, this option is ignored.
@item @samp{--single-update} file
Update tag files for a single file.
It is considered that file was added, updated or deleted,
and there is no change in other files.
This option implies the @samp{-i} option.
@item @samp{--skip-unreadable}
Skip unreadable files.
@item @samp{--skip-symlink} [=type]
Skip symbolic links. If type is 'f' then skip only symbolic links for
file, else if 'd' then skip only symbolic links for directory.
The default value of type is 'a' (all symbolic links).
@item @samp{--sqlite3}
Use Sqlite 3 API to make tag files. By default, BSD/DB 1.85 API is used.
To use this option, you need to invoke configure script with
@samp{--with-sqlite3} in the build phase.
@item @samp{--statistics}
Print statistics information.
@item @samp{-q}, @samp{--quiet}
Quiet mode.
@item @samp{-v}, @samp{--verbose}
Verbose mode.
@item @samp{--version}
Show version number.
@item @samp{-w}, @samp{--warning}
Print warning messages.
@item dbpath
The directory in which tag files are generated.
The default is the current directory.
@end table
@unnumberedsubsec EXAMPLES
@example
$ ls -F
Makefile      src/    lib/
$ gtags -v
$ global -x main
main              10 src/main.c  main (argc, argv) @{
@end example
@unnumberedsubsec FILES
@table @asis
@item @file{GTAGS}
Tag file for definitions.
@item @file{GRTAGS}
Tag file for references.
@item @file{GPATH}
Tag file for source files.
@item @file{gtags.conf}, @file{$HOME/.globalrc}
Configuration data for GNU Global.
See gtags.conf(5).
@item @file{gtags.files}
The list of candidates of target files.
@item @file{.notfunction}
The list of symbols which is not a definition.
If this file exists in the project root directory, gtags does not
regard the symbols listed in this file as definitions.
Lines starting with ';' are comment lines.

@end table
@unnumberedsubsec ENVIRONMENT
The following environment variables affect the execution of gtags:

@table @asis
@item @var{GTAGSCACHE}
The size of the B-tree cache. The default is 50000000 (bytes).
@item @var{GTAGSCONF}
Configuration file.
@item @var{GTAGSFORCECPP}
If this variable is set, each file whose suffix is @file{.h} is forcibly
parsed by the built-in C++ parser. Do not set this variable if you are
using plug-in parsers. This variable and the built-in C++ parser are deprecated.
@item @var{GTAGSFORCEENDBLOCK}
If this variable is set, each @} at the first column brings end of block
of 0 level.
@item @var{GTAGSLABEL}
Configuration label. The default is @samp{default}.
@item @var{GTAGSLOGGING}
If this variable is set, @file{$GTAGSLOGGING} is used as the path name
of a log file. There is no default value.
@item @var{GTAGS_COMMANDLINE}
This variable can only be referenced from the hook (see gtags_hook).
Gtags sets its own effective command line to this variable before
calling the hook. Each argument is separated by whitespace, and
real whitespace is represented as '%20'. This is read only.
@item @var{GTAGS_OPTIONS}
The value of this variable is inserted in the head of arguments.
@item @var{GTAGSOBJDIR}
If this variable is set, it is used as the name of BSD-style objdir.
The default is @file{obj}.
Though you can use @var{MAKEOBJDIR} instead of @var{GTAGSOBJDIR},
it is deprecated.
@item @var{GTAGSOBJDIRPREFIX}
If this variable is set, it is used as the prefix of BSD-style objdir.
The default is @file{/usr/obj}.
Though you can use @var{MAKEOBJDIRPREFIX} instead of @var{GTAGSOBJDIRPREFIX},
it is deprecated.
@item @var{TMPDIR}
The location used to stored temporary files. The default is @file{/tmp}.
@end table
@unnumberedsubsec CONFIGURATION
The following configuration variables affect the execution of gtags.
You can see the default value for each variable with the @samp{--config} option.

@table @asis
@item @code{gtags_parser} (comma separated list)
Specify the mapping of language names and plug-in parsers.
Each part delimited by the comma consists of a language name, a colon,
the shared object path, an optional colon followed by a function name.
If the function name is not specified, 'parser' is assumed.
As a special exception, gtags collects values
from multiple @code{gtags_parser} variables.
For these mappings, the first match is adopted.
@item @code{gtags_hook} (command line)
Specify a command line which should be executed at the beginning of gtags
after loading configuration file. You can use this hook to update
@file{gtags.files} dynamically.
"./" in it always means the project root directory, since gtags is
always invoked there.
@*
This hook is ignored when the following options are specified:
--version, --help, --config, --dump.
@item @code{icase_path} (boolean)
Ignore case distinctions in the path.
Suffixes check is affected by this capability.
@item @code{langmap} (comma separated list)
Language mapping. Each comma-separated map consists of
a language name, a colon, and a list of file extensions.
You can specify a glob pattern surrounded by parentheses instead of an extension
for the files without extensions (e.g. Make:([Mm]akefile).mak.mk).
As a special exception, gtags collects values
from multiple @code{langmap} variables.
For these mappings, the first match is adopted.
Default mapping is:@*
@samp{c:.c.h,yacc:.y,asm:.s.S,java:.java,cpp:.c++.cc.hh.cpp.cxx.hxx.hpp.C.H,php:.php.php3.phtml}.
@item @code{skip} (comma separated list)
Gtags skips files and directories which are given in this list.
As a special exception, gtags collects values from multiple
@code{skip} variables.
If the value ends with @samp{/}, it is assumed as a directory and
gtags skips all files under it.
The value may include glob patterns (*, ?, [...], [!...], [^...]).
@*
If the value starts with @samp{/}, it is assumed a relative path name
from the root directory of the project. You cannot use glob patterns
for a path name. However, this direction is out-of-date, and is not
recommended. Instead, you can use @samp{-f} option which can be combined with
find(1). Since find(1) has rich options to select files,
you can do everything. Additionally, this technique can also be applied
to any other tagging systems like ctags(1), cscope(1), etc. 
@*
Skip list is also effective when you use the @samp{-f} or @file{gtags.files}.
@end table
@unnumberedsubsec EXAMPLES
@example
#
# There are several ways to use Universal Ctags plug-in parser.
#
$ gtags --gtagsconf=/usr/local/share/gtags/gtags.conf --gtagslabel=universal-ctags
$ gtags --explain
or
$ export GTAGSCONF=/usr/local/share/gtags/gtags.conf
$ export GTAGSLABEL=universal-ctags
$ gtags --explain
or
# In your project
$ cp /usr/local/share/gtags/gtags.conf .
$ vi gtags.conf		# default:tc=native => default:tc=universal-ctags
$ gtags --explain
@end example
@unnumberedsubsec DIAGNOSTICS
Gtags exits with a non-0 value if an error occurred, 0 otherwise.

Note that files created by gtags with a non-zero exit code should be
considered corrupted.
@unnumberedsubsec SEE ALSO
global(1),
htags(1),
gtags.conf(5).

GNU Global source code tag system@*
(http://www.gnu.org/software/global/).
@unnumberedsubsec BUG
@file{GTAGS} and @file{GRTAGS} are very large.
In advance of using this command, check the space of your disk.

Assembly language support is far from complete.
It extracts only @code{ENTRY()} and @code{ALTENTRY()} from source file.
Probably valid only for FreeBSD and Linux kernel source.

C++ support is deprecated.

There is no concurrency control about tag files.
@unnumberedsubsec AUTHOR
Shigio YAMAGUCHI, Hideki IWAMOTO and others.
@unnumberedsubsec HISTORY
The gtags command appeared in FreeBSD 2.2.2.
