Provided by: universal-ctags_0+git20181215-2_amd64 
NAME
ctags-universal - Generate tag files for source code
SYNOPSIS
ctags-universal [options] [source_file(s)]
etags [options] [source_file(s)]
DESCRIPTION
The ctags-universal and etags programs (hereinafter collectively referred to as
ctags-universal, except where distinguished) generate an index (or "tag") file for a
variety of language objects found in source file(s). This tag file allows these items to
be quickly and easily located by a text editor or other utilities (client tools). A tag
signifies a language object for which an index entry is available (or, alternatively, the
index entry created for that object).
Alternatively, ctags-universal can generate a cross reference file which lists, in human
readable form, information about the various language objects found in a set of source
files.
Tag index files are supported by numerous editors, which allow the user to locate the
object associated with a name appearing in a source file and jump to the file and line
which defines the name. See the manual of your favorite editor about utilizing
ctags-universal command and the tag index files in the editor.
ctags-universal is capable of generating different kinds of tags for each of many
different languages. For a complete list of supported languages, the names by which they
are recognized, and the kinds of tags which are generated for each, see the
--list-languages and --list-kinds-full options.
This man page describes Universal-ctags, an implementation of ctags derived from
Exuberant-ctags. The major incompatible changes between Universal-ctags and
Exuberant-ctags are enumerated in ctags-incompatibilities(7).
One of the advantages of Exuberant-ctags is that it allows a user to define a new parser
from the command line. Extending this capability is one of the major features of
Universal-ctags. ctags-optlib(7) describes how the capability is extended.
Newly introduced experimental features are not explained here. If you are interested in
such features and ctags-universal internals, visit http://docs.ctags.io/en/latest/.
SOURCE FILES
Unless the --language-force option is specified, the language of each source file is
automatically selected based upon a mapping of file names to languages. The mappings in
effect for each language may be displayed using the --list-maps option and may be changed
using the --langmap or --map-<LANG> options.
If the name of a file is not mapped to a language, ctags-universal tries to heuristically
guess the language for the file by inspecting its content. See "Determining file
language".
All files that have no file name mapping and no guessed parser are ignored. This permits
running ctags-universal on all files in either a single directory (e.g. "ctags-universal
*"), or on all files in an entire source directory tree (e.g. "ctags-universal -R"), since
only those files whose names are mapped to languages will be scanned.
The same extensions are mapped to multiple parsers. For example, ".h" are mapped to C++, C
and ObjectiveC. These mappings can cause issues. ctags-universal tries to select the
proper parser for the source file by applying heuristics to its content, however it is not
perfect. In case of issues one can use --language-force=language,
--langmap=map[,map[...]], or the --map-<LANG>=-pattern|extension options. (Some of the
heuristics are applied whether --guess-language-eagerly is given or not.)
Determining file language
If ctags-universal cannot select a parser from the mapping of file names, various
heuristic tests are conducted to determine the language:
template file name testing
If the file name has an ".in" extension, ctags-universal applies the mapping to the
file name without the extension. For example, "config.h" is tested for a file named
"config.h.in".
interpreter testing
The first line of the file is checked to see if the file is a "#!" script for a
recognized language. ctags-universal looks for a parser having the same name.
If ctags-universal finds no such parser, ctags-universal looks for the name in
alias lists. For example, consider if the first line is "#!/bin/sh". Though
ctags-universal has a "shell" parser, it doesn't have a "sh" parser. However, "sh"
is listed as an alias for "shell", therefore ctags-universal selects the "shell"
parser for the file.
An exception is "env". If "env" is specified, ctags-universal reads more lines to
find real interpreter specification.
To display the list of aliases, use --list-aliases option. To add/remove an item
to/from the list, use the --alias-<LANG>=[+|-]aliasPattern option.
zsh autoload tag testing
If the first line starts with "#compdef" or "#autoload", ctags-universal regards
the line as "zsh".
emacs mode at the first line testing
The Emacs editor has multiple editing modes specialized for programming languages.
Emacs can recognize a marker called modeline in a file and utilize the marker for
the mode selection. This heuristic test does the same as what Emacs does.
ctags-universal treats MODE as a name of interpreter and applies the same rule of
"interpreter" testing if the first line has one of the following patterns:
-*- mode: MODE -*-
or
-*- MODE -*-
emacs mode at the EOF testing
Emacs editor recognizes another marker at the end of file as a mode specifier. This
heuristic test does the same as what Emacs does.
ctags-universal treats MODE as a name of an interpreter and applies the same rule
of "interpreter" heuristic testing, if the lines at the tail of the file have the
following pattern:
Local Variables:
...
mode: MODE
...
End:
3000 characters are sought from the end of file to find the pattern.
vim modeline testing
Like the modeline of the Emacs editor, Vim editor has the same concept.
ctags-universal treats TYPE as a name of interpreter and applies the same rule of
"interpreter" heuristic testing if the last 5 lines of the file have one of the
following patterns:
filetype=TYPE
or
ft=TYPE
PHP marker testing
If the first line is started with "<?php", ctags-universal regards the line as
"php".
Looking into the file contents is a more expensive operation than file name matching. So
ctags-universal runs the testings in limited conditions. "interpreter" testing is enabled
only when a file is an executable or the --guess-language-eagerly (-G in short) option is
given. The other heuristic tests are enabled only when -G option is given.
The --print-language option can be used just to print the results of parser selections for
given files instead of generating a tags file.
Examples:
$ ctags-universal --print-language config.h.in input.m input.unknown
config.h.in: C++
input.m: MatLab
input.unknown: NONE
NONE means that ctags-universal does not select any parser for the file.
TAG ENTRIES
A tag is an index for a language object. The concept of a tag and related items in
Exuberant-ctags are refined and extended in Universal-ctags.
A tag is categorized into definition tags or reference tags. In general, Exuberant-ctags
only tags definitions of language objects: places where newly named language objects are
introduced. Universal-ctags, on the other hand, can also tag references of language
objects: places where named language objects are used. However, support for generating
reference tags is new and limited to specific areas of specific languages in the current
version.
Fields
A tag can record various information, called fields. The essential fields are: name of
language objects, input, pattern, and line. input: is the name of source file where name:
is defined or referenced. pattern: can be used to search the name in input:. line is the
line number where name: is defined or referenced in input:.
ctags-universal offers extension fields. See also the descriptions of --list-fields option
and --fields option.
Kinds
kind: is a field which represents the kind of language object specified by a tag. Kinds
used and defined are very different between parsers. For example, C language defines
"macro", "function", "variable", "typedef", etc. See also the descriptions of
--list-kinds-full option and --kinds-<LANG> option.
Extras
Generally, ctags-universal tags only language objects appearing in source files, as is. In
other words, a value for a name: field should be found on the source file associated with
the name:. An "extra" type tag (extra) is for tagging a language object with a processed
name, or for tagging something not associated with a language object. A typical extra tag
is "qualified", which tags a language object with a class-qualified or scope-qualified
name.
The following example demonstrates the "qualified" extra tag.
package Bar;
import Baz;
class Foo {
// ...
}
For the above source file, ctags-universal tags "Bar" and "Foo" by default. If the
"qualified" extra is enabled from the command line (--extras=+q), then "Bar.Foo" is also
tagged even though the string "Bar.Foo" is not in the source code.
See also the descriptions of --list-extras option and --extras option in "OPTION ITEMS".
Roles
Role is a newly introduced concept in Universal-ctags. Role is a concept associated with
reference tags, and is not implemented widely yet.
As described previously in "Kinds", the "kind" field represents the type of language
object specified with a tag, such as a function vs. a variable. Specific kinds are
defined for reference tags, such as the C++ kind "header" for header file, or Java kind
"package" for package statements. For such reference kinds, a "roles" field can be added
to distinguish the role of the reference kind. In other words, the "kind" field identifies
the "what" of the language object, whereas the "roles" field identifies the "how" of a
referenced language object. Roles are only used with specific kinds.
For example, for the source file used for demonstrating in the "Extras" subsection, "Baz"
is tagged as a reference tag with kind "package" and with role "imported". Another example
is for a C++ "header" kind tag, generated by "#include" statements: the roles:system or
roles:local fields will be added depending on whether the include file name begins with
"<" or not.
See also the descriptions of --list-roles option.
Language-specific fields and extras
Exuberant-ctags has the concept of "fields" and "extras". They are common between parsers
of different languages. Universal-ctags extends this concept by providing
language-specific fields and extras.
COMMAND LINE INTERFACE
Despite the wealth of available options, defaults are set so that ctags-universal is most
commonly executed without any options (e.g. "ctags-universal *", or "ctags-universal
-R"), which will create a tag file in the current directory for all recognized source
files. The options described below are provided merely to allow custom tailoring to meet
special needs.
Note that spaces separating the single-letter options from their parameters are optional.
Note also that the boolean parameters to the long form options (those beginning with "--"
and that take a "[=yes|no]" parameter) may be omitted, in which case "=yes" is implied.
(e.g. --sort is equivalent to --sort=yes). Note further that "=1", "=on", and "=true" are
considered synonyms for "=yes", and that "=0", "=off", and "=false" are considered
synonyms for "=no".
Some options are either ignored or useful only when used while running in etags mode (see
-e option). Such options will be noted.
Most options may appear anywhere on the command line, affecting only those files which
follow the option. A few options, however, must appear before the first file name and will
be noted as such.
Options taking language names will accept those names in either upper or lower case. See
the --list-languages option for a complete list of the built-in language names.
Letters and names
Some options take letters as parameters (e.g. --kinds-<LANG> option). Specifying just
letters help a user create a complicated command line quickly. However, a command line
including sequences of single letters becomes difficult to understand.
Universal-ctags accepts names in addition to such letters. The names and letters can be
mixed in an option parameter by surrounding each name by braces. Thus, for an example, the
following three notations for --kinds-C option have the same meaning:
--kinds-C=+pLl
--kinds-C=+{prototype}{label}{local}
--kinds-C=+{prototype}L{local}
Note that braces may be meta characters in your shell. Put single quotes in such case.
--list-... options shows letters and associated names.
List options
Universal-ctags introduces many --list-... options that provide the internal data of
Universal-ctags. Both users and client tools may use the data. --with-list-header and
--machinable options adjust the output of the most of --list-... options.
The default setting (--with-list-header=yes and --machinable=no) is for using
interactively from a terminal. The header that explains the meaning of columns is simply
added to the output, and each column is aligned in all lines. The header line starts with
a hash ('#') character.
For scripting in a client tool, --with-list-header=no and --machinable=yes may be useful.
The header is not added to the output, and each column is separated by tab characters.
Note the order of columns will change in the future release. However, labels in the
header will not change. So by scanning the header, a client tool can find the index for
the target column.
OPTION ITEMS
ctags-universal has more options than listed here. Options starting with an underscore
character, such as --_echo=msg, are not listed here. They are experimental or for
debugging purpose.
-a Equivalent to --append.
-B Use backward searching patterns (e.g. ?pattern?). [Ignored in etags mode]
-e Same as --output-format=etags. Enable etags mode, which will create a tag file for
use with the Emacs editor. Alternatively, if ctags-universal is invoked by a name
containing the string "etags" (either by renaming, or creating a link to, the
executable), etags mode will be enabled. This option must appear before the first
file name.
-f tagfile
Use the name specified by tagfile for the tag file (default is "tags", or "TAGS"
when running in etags mode). If tagfile is specified as "-", then the tags are
written to standard output instead. ctags-universal will stubbornly refuse to take
orders if tagfile exists and its first line contains something other than a valid
tags line. This will save your neck if you mistakenly type "ctags-universal -f
*.c", which would otherwise overwrite your first C file with the tags generated by
the rest! It will also refuse to accept a multi-character file name which begins
with a '-' (dash) character, since this most likely means that you left out the tag
file name and this option tried to grab the next option as the file name. If you
really want to name your output tag file "-ugly", specify it as "./-ugly". This
option must appear before the first file name. If this option is specified more
than once, only the last will apply.
-F Use forward searching patterns (e.g. /pattern/) (default). [Ignored in etags mode]
-G Equivalent to --guess-language-eagerly.
-h list
Specifies a list of file extensions, separated by periods, which are to be
interpreted as include (or header) files. To indicate files having no extension,
use a period not followed by a non-period character (e.g. ".", "..x", ".x."). This
option only affects how the scoping of particular kinds of tags are interpreted
(i.e. whether or not they are considered as globally visible or visible only within
the file in which they are defined); it does not map the extension to any
particular language. Any tag which is located in a non-include file and cannot be
seen (e.g. linked to) from another file is considered to have file-limited (e.g.
static) scope. No kind of tag appearing in an include file will be considered to
have file-limited scope. If the first character in the list is a plus sign, then
the extensions in the list will be appended to the current list; otherwise, the
list will replace the current list. See, also, the --file-scope option. The default
list is ".h.H.hh.hpp.hxx.h++.inc.def". To restore the default list, specify -h
default. Note that if an extension supplied to this option is not already mapped to
a particular language (see "SOURCE FILES", above), you will also need to use either
the --langmap or --language-force option.
-I identifier-list
Specifies a list of identifiers which are to be specially handled while parsing C
and C++ source files. This option is specifically provided to handle special cases
arising through the use of preprocessor macros. When the identifiers listed are
simple identifiers, these identifiers will be ignored during parsing of the source
files. If an identifier is suffixed with a '+' character, ctags-universal will also
ignore any parenthesis-enclosed argument list which may immediately follow the
identifier in the source files. If two identifiers are separated with the '='
character, the first identifiers is replaced by the second identifiers for parsing
purposes. The list of identifiers may be supplied directly on the command line or
read in from a separate file. If the first character of identifier-list is '@',
'.' or a pathname separator ('/' or ''), or the first two characters specify a
drive letter (e.g. "C:"), the parameter identifier-list will be interpreted as a
filename from which to read a list of identifiers, one per input line. Otherwise,
identifier-list is a list of identifiers (or identifier pairs) to be specially
handled, each delimited by either a comma or by white space (in which case the list
should be quoted to keep the entire list as one command line argument). Multiple -I
options may be supplied. To clear the list of ignore identifiers, supply a single
dash ("-") for identifier-list.
This feature is useful when preprocessor macros are used in such a way that they
cause syntactic confusion due to their presence. Indeed, this is the best way of
working around a number of problems caused by the presence of syntax-busting macros
in source files (see "CAVEATS"). Some examples will illustrate this point.
int foo ARGDECL4(void *, ptr, long int, nbytes)
In the above example, the macro "ARGDECL4" would be mistakenly interpreted to be
the name of the function instead of the correct name of "foo". Specifying "-I
ARGDECL4" results in the correct behavior.
/* creates an RCS version string in module */
MODULE_VERSION("$Revision$")
In the above example the macro invocation looks too much like a function definition
because it is not followed by a semicolon (indeed, it could even be followed by a
global variable definition that would look much like a K&R style function parameter
declaration). In fact, this seeming function definition could possibly even cause
the rest of the file to be skipped over while trying to complete the definition.
Specifying "-I MODULE_VERSION+" would avoid such a problem.
CLASS Example {
// your content here
};
The example above uses "CLASS" as a preprocessor macro which expands to something
different for each platform. For instance CLASS may be defined as "class
__declspec(dllexport)" on Win32 platforms and simply "class" on UNIX. Normally, the
absence of the C++ keyword "class" would cause the source file to be incorrectly
parsed. Correct behavior can be restored by specifying "-I CLASS=class".
-L file
Read from file a list of file names for which tags should be generated. If file is
specified as "-", then file names are read from standard input. File names read
using this option are processed following file names appearing on the command line.
Options are also accepted in this input. If this option is specified more than
once, only the last will apply. Note: file is read in line-oriented mode, where a
new line is the only delimiter and non-trailing white space is considered
significant, in order that file names containing spaces may be supplied (however,
trailing white space is stripped from lines); this can affect how options are
parsed if included in the input.
-n Equivalent to --excmd=number.
-N Equivalent to --excmd=pattern.
-o tagfile
Equivalent to -f tagfile.
-R Equivalent to --recurse.
-u Equivalent to --sort=no (i.e. "unsorted").
-V Equivalent to --verbose.
-w This option is silently ignored for backward-compatibility with the ctags of SVR4
Unix.
-x Print a tabular, human-readable cross reference (xref) file to standard output
instead of generating a tag file. The information contained in the output includes:
the tag name; the kind of tag; the line number, file name, and source line (with
extra white space condensed) of the file which defines the tag. No tag file is
written and all options affecting tag file output will be ignored. Example
applications for this feature are generating a listing of all functions located in
a source file (e.g. "ctags-universal -x --c-kinds=f file"), or generating a list of
all externally visible global variables located in a source file (e.g.
"ctags-universal -x --c-kinds=v --file-scope=no file"). This option must appear
before the first file name.
--alias-<LANG>=[+|-]aliasPattern
Adds ('+') or removes ('-') an alias pattern to a language specified with <LANG>.
ctags-universal refers to the alias pattern in "Determining file language" stage.
The parameter aliasPattern is not a list. Use this option multiple times in a
command line to add or remove multiple alias patterns.
To restore the default language aliases, specify "default" as the parameter
aliasPattern. Using "all" for <LANG> has meaning in following two cases:
--alias-all=
This clears aliases setting of all languages.
--alias-all=default
This restores the default languages aliases for all languages.
--append[=yes|no]
Indicates whether tags generated from the specified files should be appended to
those already present in the tag file or should replace them. This option is "no"
by default. This option must appear before the first file name.
--etags-include=file
Include a reference to file in the tag file. This option may be specified as many
times as desired. This supports Emacs' capability to use a tag file which
"includes" other tag files. [Available only in etags mode]
--exclude=[pattern]
Add pattern to a list of excluded files and directories. This option may be
specified as many times as desired. For each file name considered by
ctags-universal, each pattern specified using this option will be compared against
both the complete path (e.g. some/path/base.ext) and the base name (e.g. base.ext)
of the file, thus allowing patterns which match a given file name irrespective of
its path, or match only a specific path. If appropriate support is available from
the runtime library of your C compiler, then pattern may contain the usual shell
wildcards (not regular expressions) common on Unix (be sure to quote the option
parameter to protect the wildcards from being expanded by the shell before being
passed to ctags-universal; also be aware that wildcards can match the slash
character, '/'). You can determine if shell wildcards are available on your
platform by examining the output of the --list-features option, which will include
"wildcards" in the compiled feature list; otherwise, pattern is matched against
file names using a simple textual comparison.
If pattern begins with the character '@', then the rest of the string is
interpreted as a file name from which to read exclusion patterns, one per line. If
pattern is empty, the list of excluded patterns is cleared.
Note that at program startup, the default exclude list contains names of common
hidden and system files, patterns for binary files, and directories for which it is
generally not desirable to descend while processing the --recurse option. To see
the list of built-in exclude patterns, use --list-excludes.
--excmd=type
Determines the type of EX command used to locate tags in the source file. [Ignored
in etags mode]
The valid values for type (either the entire word or the first letter is accepted)
are:
number Use only line numbers in the tag file for locating tags. This has four
advantages:
1. Significantly reduces the size of the resulting tag file.
2. Eliminates failures to find tags because the line defining the tag has
changed, causing the pattern match to fail (note that some editors, such
as vim, are able to recover in many such instances).
3. Eliminates finding identical matching, but incorrect, source lines (see
"BUGS").
4. Retains separate entries in the tag file for lines which are identical in
content. In pattern mode, duplicate entries are dropped because the
search patterns they generate are identical, making the duplicate entries
useless.
However, this option has one significant drawback: changes to the source
files can cause the line numbers recorded in the tag file to no longer
correspond to the lines in the source file, causing jumps to some tags to
miss the target definition by one or more lines. Basically, this option is
best used when the source code to which it is applied is not subject to
change. Selecting this option type causes the following options to be
ignored: -BF.
pattern
Use only search patterns for all tags, rather than the line numbers usually
used for macro definitions. This has the advantage of not referencing
obsolete line numbers when lines have been added or removed since the tag
file was generated.
mixed In this mode, patterns are generally used with a few exceptions. For C,
line numbers are used for macro definition tags. This was the default format
generated by the original ctags and is, therefore, retained as the default
for this option. For Fortran, line numbers are used for common blocks
because their corresponding source lines are generally identical, making
pattern searches useless for finding all matches.
--extra=[+|-]flags|*
Equivalent to --extras=[+|-]flags|*, which was introduced to make the option naming
convention align to the other options like --kinds-<LANG>= and --fields=.
This option is kept for backward-compatibility with Exuberant-ctags.
--extras=[+|-]flags|*
Specifies whether to include extra tag entries for certain kinds of information.
See also "Extras" subsection to know what are kinds.
The parameter flags is a set of one-letter flags, each representing one kind of
extra tag entry to include in the tag file. If flags is preceded by either the '+'
or '-' character, the effect of each flag is added to, or removed from, those
currently enabled; otherwise the flags replace any current settings. All entries
are included if '*' is given.
This --extras= option is for controlling extras common in all languages (or
language-independent extras). Universal-ctags also supports language-specific
extras. (See "Language-specific fields and extras" about the concept). Use
--extras-<LANG>= option for controlling them.
The meaning of major extras is as follows (one-letter flag/name):
F/fileScope
Equivalent to --file-scope.
f/inputFile
Include an entry for the base file name of every source file (e.g.
"example.c"), which addresses the first line of the file. If the end: field
is enabled, the end line number of the file can be attached to the tag.
p/pseudo
Include pseudo tags. Enabled by default unless the tag file is written to
standard output.
q/qualified
Include an extra class-qualified or namespace-qualified tag entry for each
tag which is a member of a class or a namespace.
This may allow easier location of a specific tags when multiple occurrences
of a tag name occur in the tag file. Note, however, that this could
potentially more than double the size of the tag file.
The actual form of the qualified tag depends upon the language from which
the tag was derived (using a form that is most natural for how qualified
calls are specified in the language). For C++ and Perl, it is in the form
"class::member"; for Eiffel and Java, it is in the form "class.member".
Note: Using backslash characters as separators forming qualified name in
PHP. However, in tags output of Universal-ctags, a backslash character in a
name is escaped with a backslash character.
r/reference
Include reference tags. See "TAG ENTRIES" about reference tags.
Inquire the output of --list-extras option for the other minor extras.
A name associated with an extra can be used as alternative to a one-letter flag.
Some minor extras have no one-letters flag. In that case, names must be specified
anyway. See "Letters and names" for more details.
--extras-<LANG>=[+|-]flags|*
Specifies whether to include extra tag entries for certain kinds of information for
language <LANG>. Universal-ctags introduces language-specific extras. (See
"Language-specific fields and extras" about the concept). This option is for
controlling them.
Specifies "all" as <LANG> to apply the parameter flags to all languages; all extras
are enabled with specifying '*' as the parameter flags. If specifying nothing as
the parameter flags ("--extras-all="), all extras are disabled. These two
combinations are useful for testing.
Check the output of the --list-extras=<LANG> option for the extras of specific
language <LANG>.
--fields-<LANG>=[+|-]flags|*
Specifies which language-specific fields are to be included in the entries of the
tag file. Universal-ctags supports language-specific fields. (See
"Language-specific fields and extras" about the concept). This option is for
controlling them.
Specify "all" as <LANG> to apply the parameter flags to all fields; all fields are
enabled with specifying '*' as the parameter flags. If specifying nothing as the
parameter flags ("--fields-all="), all extras are disabled. These two combinations
are useful for testing.
--fields=[+|-]flags|*
Specifies which available extension fields are to be included in the tag entries
(see "TAG FILE FORMAT", below, and, "Fields", above, for more information).
The parameter flags is a set of one-letter flags, each representing one type of
extension field to include. Each letter or group of letters may be preceded by
either '+' to add it to the default set, or '-' to exclude it. In the absence of
any preceding '+' or '-' sign, only those fields explicitly listed in flags will be
included in the output (i.e. overriding the default set). All fields are included
if '*' is given. This option is ignored if the option --format=1 (legacy tag file
format) has been specified.
This --fields= option is for controlling fields common in all languages (or
language-independent fields). Universal-ctags also supports language-specific
fields. (See "Language-specific fields and extras" about the concept). Use
--fields-<LANG>= option for controlling them.
The meaning of major fields is as follows (one-letter flag/name):
a/access
Access (or export) of class members
e/end End lines of various items
f/file File-restricted scoping. Enabled by default.
i/inherits
Inheritance information.
k Kind of tag as a single letter. Enabled by default. Exceptionally this has
no name.
K Kind of tag as full name Exceptionally this has no name.
l/language
Language of source file containing tag
m/implementation
Implementation information
n/line Line number of tag definition
p/scopeKind
Kind of scope as full name
r/roles
Roles assigned to the tag. For a definition tag, this field takes "def" as
a value.
s Scope of tag definition. Enabled by default. Exceptionally this has no
name.
S/signature
Signature of routine (e.g. prototype or parameter list)
t/typeref
Type and name of a variable, typedef or return type of callable like
function as "typeref:" field. Enabled by default.
z/kind Include the "kind:" key in kind field
Z Include the "scope:" key in scope field. Exceptionally this has no name.
Check the output of the --list-fields option for the other minor fields.
A name associated with a field can be used as alternative to a one-letter flag.
Some minor fields have no one-letters flag. In that case, names must be specified
anyway. See "Letters and names" for more details.
--file-scope[=yes|no]
Indicates whether tags scoped only for a single file (i.e. tags which cannot be
seen outside of the file in which they are defined, such as "static" tags) should
be included in the output. See, also, the -h option. This option is enabled by
default.
Universal-ctags provides an alternative way to control this option, with the
"F/fileScope" extra, and recommends users to use the extra. However, this extra can
cause issues. See ctags-incompatibilities(7).
--filter[=yes|no]
Makes ctags-universal behave as a filter, reading source file names from standard
input and printing their tags to standard output on a file-by-file basis. If --sort
is enabled, tags are sorted only within the source file in which they are defined.
File names are read from standard input in line-oriented input mode (see note for
-L option) and only after file names listed on the command line or from any file
supplied using the -L option. When this option is enabled, the options -f, -o, and
--totals are ignored. This option is quite esoteric and is disabled by default.
This option must appear before the first file name.
--filter-terminator=string
Specifies a string to print to standard output following the tags for each file
name parsed when the --filter option is enabled. This may permit an application
reading the output of ctags-universal to determine when the output for each file is
finished. Note that if the file name read is a directory and --recurse is enabled,
this string will be printed only once at the end of all tags found for by
descending the directory. This string will always be separated from the last tag
line for the file by its terminating newline. This option is quite esoteric and is
empty by default. This option must appear before the first file name.
--format=level
Change the format of the output tag file. Currently the only valid values for level
are 1 or 2. Level 1 specifies the original tag file format and level 2 specifies a
new extended format containing extension fields (but in a manner which retains
backward-compatibility with original vi(1) implementations). The default level is
2. This option must appear before the first file name. [Ignored in etags mode]
--guess-language-eagerly
Looks into the file contents for heuristically guessing the proper language parser.
See "Determining file language".
--help Prints to standard output a detailed usage description, and then exits.
--help-full
Prints to standard output a detailed usage description about experimental features,
and then exits. Visit http://docs.ctags.io/en/latest for information about the
latest exciting experimental features.
--if0[=yes|no]
Indicates a preference as to whether code within an "#if 0" branch of a
preprocessor conditional should be examined for non-macro tags (macro tags are
always included). Because the intent of this construct is to disable code, the
default value of this option is no. Note that this indicates a preference only and
does not guarantee skipping code within an "#if 0" branch, since the fall-back
algorithm used to generate tags when preprocessor conditionals are too complex
follows all branches of a conditional. This option is disabled by default.
--kinddef-<LANG>=letter,name,description
See ctags-optlib(7). Be not confused this with --kinds-<LANG>.
--kinds-<LANG>=[+|-]kinds|*
Specifies a list of language-specific kinds of tags (or kinds) to include in the
output file for a particular language, where <LANG> is case-insensitive and is one
of the built-in language names (see the --list-languages option for a complete
list). The parameter kinds is a group of one-letter flags designating kinds of tags
(particular to the language) to either include or exclude from the output. The
specific sets of flags recognized for each language, their meanings and defaults
may be list using the --list-kinds-full option. Each letter or group of letters may
be preceded by either '+' to add it to, or '-' to remove it from, the default set.
In the absence of any preceding '+' or '-' sign, only those kinds explicitly listed
in kinds will be included in the output (i.e. overriding the default for the
specified language).
Specify '*' as the parameter to include all kinds implemented in <LANG> in the
output. Furthermore if "all" is given as <LANG>, specification of the parameter
kinds affects all languages defined in ctags-universal. Giving "all" makes sense
only when '*' is given as the parameter kinds.
As an example for the C language, in order to add prototypes and external variable
declarations to the default set of tag kinds, but exclude macros, use
"--c-kinds=+px-d"; to include only tags for functions, use "--c-kinds=f".
A name associated with a kind can be used as alternative to a one-letter flag. See
"Letters and names" for more details.
--<LANG>-kinds=[+|-]kinds|*
Equivalent to --kinds-<LANG>=.... This option is kept for backward-compatibility
with Exuberant-ctags.
--langdef=name
See ctags-optlib(7).
--langmap=map[,map[...]]
Controls how file names are mapped to languages (see the --list-maps option). Each
comma-separated map consists of the language name (either a built-in or
user-defined language), a colon, and a list of file extensions and/or file name
patterns. A file extension is specified by preceding the extension with a period
(e.g. ".c"). A file name pattern is specified by enclosing the pattern in
parentheses (e.g. "([Mm]akefile)").
If appropriate support is available from the runtime library of your C compiler,
then the file name pattern may contain the usual shell wildcards common on Unix (be
sure to quote the option parameter to protect the wildcards from being expanded by
the shell before being passed to ctags-universal). You can determine if shell
wildcards are available on your platform by examining the output of the
--list-features option, which will include "wildcards" in the compiled feature
list; otherwise, the file name patterns are matched against file names using a
simple textual comparison.
When mapping a file extension with --langmap option, it will first be unmapped from
any other languages. (--map-<LANG> option provides more fine-grained control.)
If the first character in a map is a plus sign ('+'), then the extensions and file
name patterns in that map will be appended to the current map for that language;
otherwise, the map will replace the current map. For example, to specify that only
files with extensions of .c and .x are to be treated as C language files, use
"--langmap=c:.c.x"; to also add files with extensions of .j as Java language files,
specify "--langmap=c:.c.x,java:+.j". To map makefiles (e.g. files named either
"Makefile", "makefile", or having the extension ".mak") to a language called
"make", specify "--langmap=make:([Mm]akefile).mak". To map files having no
extension, specify a period not followed by a non-period character (e.g. ".",
"..x", ".x.").
To clear the mapping for a particular language (thus inhibiting automatic
generation of tags for that language), specify an empty extension list (e.g.
"--langmap=fortran:"). To restore the default language mappings for a particular
language, supply the keyword "default" for the mapping. To specify restore the
default language mappings for all languages, specify "--langmap=default".
Note that file name patterns are tested before file extensions when inferring the
language of a file. This order of Universal-ctags is different from
Exuberant-ctags. See ctags-incompatibilities(7) for the background of this
incompatible change.
--language-force=language
By default, ctags-universal automatically selects the language of a source file,
ignoring those files whose language cannot be determined (see "SOURCE FILES",
above). This option forces the specified language (case-insensitive; either
built-in or user-defined) to be used for every supplied file instead of
automatically selecting the language based upon its extension. In addition, the
special value "auto" indicates that the language should be automatically selected
(which effectively disables this option).
--languages=[+|-]list
Specifies the languages for which tag generation is enabled, with list containing a
comma-separated list of language names (case-insensitive; either built-in or
user-defined). If the first language of list is not preceded by either a '+' or
'-', the current list (the current settings of enabled/disabled languages managed
in ctags-universal internally) will be cleared before adding or removing the
languages in list. Until a '-' is encountered, each language in the list will be
added to the current list. As either the '+' or '-' is encountered in the list,
the languages following it are added or removed from the current list,
respectively. Thus, it becomes simple to replace the current list with a new one,
or to add or remove languages from the current list.
The actual list of files for which tags will be generated depends upon the language
extension mapping in effect (see the --langmap option). Note that the most of all
languages, including user-defined languages, are enabled unless explicitly disabled
using this option. Language names included in list may be any built-in language or
one previously defined with --langdef. The default is "all", which is also accepted
as a valid argument. See the --list-languages option for a list of the all
(built-in and user-defined) language names.
Note --languages= option works cumulative way; the option can be specified with
different arguments multiple times in a command line.
--license
Prints a summary of the software license to standard output, and then exits.
--line-directives[=yes|no]
Specifies whether "#line" directives should be recognized. These are present in the
output of preprocessors and contain the line number, and possibly the file name, of
the original source file(s) from which the preprocessor output file was generated.
When enabled, this option will cause ctags-universal to generate tag entries marked
with the file names and line numbers of their locations original source file(s),
instead of their actual locations in the preprocessor output. The actual file names
placed into the tag file will have the same leading path components as the
preprocessor output file, since it is assumed that the original source files are
located relative to the preprocessor output file (unless, of course, the #line
directive specifies an absolute path). This option is off by default. Note: This
option is generally only useful when used together with the --excmd=number (-n)
option. Also, you may have to use either the --langmap or --language-force option
if the extension of the preprocessor output file is not known to ctags-universal.
--links[=yes|no]
Indicates whether symbolic links (if supported) should be followed. When disabled,
symbolic links are ignored. This option is on by default.
--list-aliases[=language|all]
Lists the aliases for either the specified language or all languages, and then
exits. The aliases are used when heuristically testing a language parser for a
source file.
--list-excludes
Lists the current exclusion patterns used to exclude files.
--list-extras[=languages|all]
Lists the extras recognized for either the specified language or "all" languages.
See "Extras" subsection to know what are extras.
An extra can be enabled or disabled with --extras= for common extras in all
languages, or --extras-<LANG>= for the specified language. These option takes
one-letter flag or name as a parameter for specifying an extra.
The meaning of columns are as follows:
LETTER One-letter flag. '-' means the extra does not have one-letter flag.
NAME The name of extra. The name is used in extras: field.
ENABLED
Whether the extra is enabled or not. It takes "yes" or "no".
LANGUAGE
The name of language if the extra is owned by a parser. "NONE" means the
extra is common in parsers.
DESCRIPTION
Human readable description for the extra.
--list-features
Lists the compiled features.
--list-fields[=language|all]
Lists the fields recognized for either the specified language or "all" languages.
See "Fields" subsection to know what are fields.
A field can be enabled or disabled with --fields= for common extras in all
languages, or --fields-<LANG>= for the specified language. These option takes
one-letter flag or name as a parameter for specifying a field.
The meaning of columns are as follows:
LETTER One-letter flag. '-' means the field does not have one-letter flag.
NAME The name of field.
ENABLED
Whether the field is enabled or not. It takes "yes" or "no".
LANGUAGE
The name of language if the field is owned by a parser. "NONE" means the
extra is common in parsers.
JSTYPE Json type used in printing the value of field when "--output-format=json" is
specified.
Following characters are used for representing types.
s string
i integer
b boolean (true or false)
The representation of this field and the output format used in
"--output-format=json" are still experimental.
FIXED Whether this field can be disabled or not. Some fields are printed always in
tags output. They have "yes" as the value for this column.
DESCRIPTION
Human readable description for the field.
--list-kinds[=language|all]
Subset of --list-kinds-full. This option is kept for backward-compatibility with
Exuberant-ctags.
This option prints only LETTER, DESCRIPTION, and ENABLED fields of
--list-kinds-full output. However, the presentation of ENABLED column is different
from that of --list-kinds-full option; "[off]" follows after description if the
kind is disabled, and nothing follows if enabled. The most of all kinds are
enabled by default.
The critical weakness of this option is that this option does not print the name of
kind. Universal-ctags introduces --list-kinds-full because it considers that names
are important.
This option does not work with --machinable nor --with-list-header.
--list-kinds-full[=language|all]
Lists the tag kinds recognized for either the specified language or "all"
languages, and then exits. See "Kinds" subsection to learn what kinds are.
Each kind of tag recorded in the tag file is represented by a one-letter flag, or
name. They are also used to filter the tags placed into the output through use of
the --kinds-<LANG> option.
The meaning of columns are as follows:
LANGUAGE
The name of language having the kind.
LETTER One-letter flag. This must be unique in a language.
NAME Name of the kind. This can be used as the alternative one-letter flag
described above. If enabling 'K' field with --fields=+K, ctags-universal
uses name instead of letter in tags output. To enable/disable a kind with
--kinds-<LANG> option, name surrounded by braces instead of letter. See
"Letters and names" for details. This must be unique in a language.
ENABLED
Whether the kind is enabled or not. It takes "yes" or "no".
REFONLY
Whether the kind is specialized for reference tagging or not. If the column
is "yes", the kind is for reference tagging, and it is never used for
definition tagging. See also "TAG ENTRIES".
NROLES The number of roles this kind has. See also "Roles".
MASTER The master parser controlling enablement of the kind. A kind belongs to a
language (owner) in Universal-ctags; enabling and disabling a kind in a
language has no effect on a kind in another language even if both kinds has
the same letter and/or the same name. In other words, the namespace of kinds
are separated by language.
However, Exuberant-ctags does not separate the kinds of C and C++.
Enabling/disabling kindX in C language enables/disables a kind in C++
language having the same name with kindX. To emulate this behavior in
Universal-ctags, a concept named "master parser" is introduced.
Enabling/disabling some kinds are synchronized under the control of a master
language.
$ ctags --kinds-C=+'{local}' --list-kinds-full \
| grep -E '^(#|C\+\+ .* local)'
#LANGUAGE LETTER NAME ENABLED REFONLY NROLES MASTER DESCRIPTION
C++ l local yes no 0 C local variables
$ ctags --kinds-C=-'{local}' --list-kinds-full \
| grep -E '^(#|C\+\+ .* local)'
#LANGUAGE LETTER NAME ENABLED REFONLY NROLES MASTER DESCRIPTION
C++ l local no no 0 C local variables
You see "ENABLED" field of "local" kind of C++ language is changed Though
"local" kind of C language is enabled/disabled. If you swap the languages,
you see the same result.
DESCRIPTION
Human readable description for the kind.
--list-languages
Lists the names of the languages understood by ctags-universal, and then exits.
These language names are case insensitive and may be used in many other options
like --language-force, --languages, --kinds-<LANG>, --regex-<LANG>, and so on.
Each language listed is disabled if followed by "[disabled]". To use the parser
for such a language, specify the language as an argument of --languages=+ option.
This option does not work with --machinable nor --with-list-header.
--list-map-extensions[=language|all]
Lists the file extensions which associate a file name with a language for either
the specified language or all languages, and then exits.
--list-map-patterns[=language|all]
Lists the file name patterns which associate a file name with a language for either
the specified language or all languages, and then exits.
--list-maps[=language|all]
Lists file name patterns and the file extensions which associate a file name with a
language for either the specified language or all languages, and then exits. See
the --langmap option, and "SOURCE FILES", above.
To list the file extensions or file name patterns individually, use
--list-map-extensions or --list-map-patterns option. See the --langmap option, and
"SOURCE FILES", above.
This option does not work with --machinable nor --with-list-header.
--list-regex-flags
See ctags-optlib(7).
--list-roles[=language|all[.kinds]]
List the roles for either the specified language or "all" languages. If the
parameter kinds is given after the parameter language or "all" with concatenating
with '.', list only roles defined in the kinds. Both one-letter flags and names
surrounded by braces are acceptable as the parameter kinds.
The meaning of columns are as follows:
LANGUAGE
Name of language having the role.
KIND(L/N)
One-letter flag and name of kind having the role.
NAME Name of the role.
ENABLED
Whether the kind is enabled or not. It takes "yes" or "no". (Currently all
roles are enabled. No option for disabling a specified role is not
implemented yet.)
DESCRIPTION
Human readable description for the role.
--machinable[=yes|no]
Use tab character as separators for --list- option output. It may be suitable for
scripting. See "List options" for considered use cases. Disabled by default.
--map-<LANG>=[+|-]extension|pattern
This option provides the way to control mapping(s) of file names to languages in a
more fine-grained way than --langmap option.
In ctags-universal, more than one language can map to a file name pattern or file
extension (N:1 map). Alternatively, --langmap option handle only 1:1 map, only one
language mapping to one file name pattern or file extension. A typical N:1 map is
seen in C++ and ObjectiveC language; both languages have a map to ".h" as a file
extension.
A file extension is specified by preceding the extension with a period (e.g. ".c").
A file name pattern is specified by enclosing the pattern in parentheses (e.g.
"([Mm]akefile)"). A prefixed plus ('+') sign is for adding, and minus ('-') is for
removing. No prefix means replacing the map of <LANG>.
Unlike --langmap, extension (or pattern) is not a list. --map-<LANG> takes one
extension (or pattern). However, the option can be specified with different
arguments multiple times in a command line.
--maxdepth
Limits the depth of directory recursion enabled with the --recurse (-R) option.
--options=pathname
Read additional options from file or directory.
ctags-universal searches pathname in optlib path list first. If ctags-universal
cannot find a file or directory in the list, ctags-universal reads a file or
directory at the specified pathname.
If a file is specified, it should contain one option per line. If a directory is
specified, files suffixed with ".ctags" under it are read in alphabetical order.
As a special case, if "--options=NONE" is specified as the first option on the
command line, preloading is disabled; the option will disable the automatic reading
of any configuration options from either a file or the environment (see "FILES").
--options-maybe=pathname
Same as --options but doesn't cause an error if file (or directory) specified with
pathname doesn't exist.
--optlib-dir=[+]directory
Add an optlib directory to or reset optlib path list. By default, the optlib path
list is empty.
--print-language
Just prints the language parsers for specified source files, and then exits.
--quiet[=yes|no]
Write fewer messages (default is no).
--recurse[=yes|no]
Recurse into directories encountered in the list of supplied files. If the list of
supplied files is empty and no file list is specified with the -L option, then the
current directory (i.e. ".") is assumed. Symbolic links are followed. If you don't
like these behaviors, either explicitly specify the files or pipe the output of
find(1) into ctags-universal -L- instead. Note: This option is not supported on all
platforms at present. It is available if the output of the --help option includes
this option. See, also, the --exclude to limit recursion.
--regex-<LANG>=/regexp/replacement/[kind-spec/][flags]
See ctags-optlib(7).
--sort[=yes|no|foldcase]
Indicates whether the tag file should be sorted on the tag name (default is yes).
Note that the original vi(1) required sorted tags. The foldcase value specifies
case insensitive (or case-folded) sorting. Fast binary searches of tag files
sorted with case-folding will require special support from tools using tag files,
such as that found in the ctags-universal readtags library, or Vim version 6.2 or
higher (using "set ignorecase"). This option must appear before the first file
name. [Ignored in etags mode]
--tag-relative[=yes|no]
Indicates that the file paths recorded in the tag file should be relative to the
directory containing the tag file, rather than relative to the current directory,
unless the files supplied on the command line are specified with absolute paths.
This option must appear before the first file name. The default is yes when running
in etags mode (see the -e option), no otherwise.
--totals[=yes|no]
Prints statistics about the source files read and the tag file written during the
current invocation of ctags-universal. This option is off by default. This option
must appear before the first file name.
--verbose[=yes|no]
Enable verbose mode. This prints out information on option processing and a brief
message describing what action is being taken for each file considered by
ctags-universal. Normally, ctags-universal does not read command line arguments
until after options are read from the configuration files (see "FILES", below) and
the CTAGS environment variable. However, if this option is the first argument on
the command line, it will take effect before any options are read from these
sources. The default is no.
--version
Prints a version identifier for ctags-universal to standard output, and then exits.
This is guaranteed to always contain the string "Universal Ctags".
--with-list-header[=yes|no]
Print headers describing columns in --list- option output. See also "List
options".
OPERATIONAL DETAILS
As ctags-universal considers each file name in turn, it tries to determine the language of
the file by applying the following three tests in order: if the file extension has been
mapped to a language, if the filename matches a shell pattern mapped to a language, and
finally if the file is executable and its first line specifies an interpreter using the
Unix-style "#!" specification (if supported on the platform). Additionallly, if the
--guess-language-eagerly option is given, heuristic testing is also performed to determine
if a language parser applies. (See "Determining file language")
If a language was identified, the file is opened and then the appropriate language parser
is called to operate on the currently open file. The parser parses through the file and
adds an entry to the tag file for each language object it is written to handle. See "TAG
FILE FORMAT", below, for details on these entries.
This implementation of ctags-universal imposes no formatting requirements on C code as do
legacy implementations. Older implementations of ctags tended to rely upon certain
formatting assumptions in order to help it resolve coding dilemmas caused by preprocessor
conditionals.
In general, ctags-universal tries to be smart about conditional preprocessor directives.
If a preprocessor conditional is encountered within a statement which defines a tag,
ctags-universal follows only the first branch of that conditional (except in the special
case of "#if 0", in which case it follows only the last branch). The reason for this is
that failing to pursue only one branch can result in ambiguous syntax, as in the following
example:
#ifdef TWO_ALTERNATIVES
struct {
#else
union {
#endif
short a;
long b;
}
Both branches cannot be followed, or braces become unbalanced and ctags-universal would be
unable to make sense of the syntax.
If the application of this heuristic fails to properly parse a file, generally due to
complicated and inconsistent pairing within the conditionals, ctags-universal will retry
the file using a different heuristic which does not selectively follow conditional
preprocessor branches, but instead falls back to relying upon a closing brace ("}") in
column 1 as indicating the end of a block once any brace imbalance results from following
a #if conditional branch.
ctags-universal will also try to specially handle arguments lists enclosed in double sets
of parentheses in order to accept the following conditional construct:
extern void foo __ARGS((int one, char two));
Any name immediately preceding the "((" will be automatically ignored and the previous
name will be used.
C++ operator definitions are specially handled. In order for consistency with all types of
operators (overloaded and conversion), the operator name in the tag file will always be
preceded by the string "operator " (i.e. even if the actual operator definition was
written as "operator<<").
After creating or appending to the tag file, it is sorted by the tag name, removing
identical tag lines.
TAG FILE FORMAT
When not running in etags mode, each entry in the tag file consists of a separate line,
each looking like this in the most general case:
tag_name<TAB>file_name<TAB>ex_cmd;"<TAB>extension_fields
The fields and separators of these lines are specified as follows:
1. tag name
2. single tab character
3. name of the file in which the object associated with the tag is located
4. single tab character
5. EX command used to locate the tag within the file; generally a search pattern
(either /pattern/ or ?pattern?) or line number (see --excmd). Tag file format 2 (see
--format) extends this EX command under certain circumstances to include a set of
extension fields (described below) embedded in an EX comment immediately appended to
the EX command, which leaves it backward-compatible with original vi(1)
implementations.
A few special tags are written into the tag file for internal purposes. These tags are
composed in such a way that they always sort to the top of the file. Therefore, the first
two characters of these tags are used a magic number to detect a tag file for purposes of
determining whether a valid tag file is being overwritten rather than a source file.
Note that the name of each source file will be recorded in the tag file exactly as it
appears on the command line. Therefore, if the path you specified on the command line was
relative to the current directory, then it will be recorded in that same manner in the tag
file. See, however, the --tag-relative option for how this behavior can be modified.
Extension fields are tab-separated key-value pairs appended to the end of the EX command
as a comment, as described above. These key value pairs appear in the general form
"key:value". Their presence in the lines of the tag file are controlled by the --fields
option. The possible keys and the meaning of their values are as follows:
access Indicates the visibility of this class member, where value is specific to the
language.
file Indicates that the tag has file-limited visibility. This key has no corresponding
value.
kind Indicates the type, or kind, of tag. Its value is either one of the corresponding
one-letter flags described under the various --kinds-<LANG> options above, or a
full name. It is permitted (and is, in fact, the default) for the key portion of
this field to be omitted. The optional behaviors are controlled with the --fields
option.
implementation
When present, this indicates a limited implementation (abstract vs. concrete) of a
routine or class, where value is specific to the language ("virtual" or "pure
virtual" for C++; "abstract" for Java).
inherits
When present, value. is a comma-separated list of classes from which this class is
derived (i.e. inherits from).
signature
When present, value is a language-dependent representation of the signature of a
routine. A routine signature in its complete form specifies the return type of a
routine and its formal argument list. This extension field is presently supported
only for C-based languages and does not include the return type.
In addition, information on the scope of the tag definition may be available, with the key
portion equal to some language-dependent construct name and its value the name declared
for that construct in the program. This scope entry indicates the scope in which the tag
was found. For example, a tag generated for a C structure member would have a scope
looking like "struct:myStruct".
HOW TO USE WITH VI
Vi will, by default, expect a tag file by the name "tags" in the current directory. Once
the tag file is built, the following commands exercise the tag indexing feature:
vi -t tag
Start vi and position the cursor at the file and line where "tag" is defined.
:ta tag
Find a tag.
Ctrl-] Find the tag under the cursor.
Ctrl-T Return to previous location before jump to tag (not widely implemented).
HOW TO USE WITH GNU EMACS
Emacs will, by default, expect a tag file by the name "TAGS" in the current directory.
Once the tag file is built, the following commands exercise the tag indexing feature:
M-x visit-tags-table <RET> FILE <RET>
Select the tag file, "FILE", to use.
M-. [TAG] <RET>
Find the first definition of TAG. The default tag is the identifier under the
cursor.
M-* Pop back to where you previously invoked "M-.".
C-u M-.
Find the next definition for the last tag.
For more commands, see the Tags topic in the Emacs info document.
HOW TO USE WITH NEDIT
NEdit version 5.1 and later can handle the new extended tag file format (see --format). To
make NEdit use the tag file, select "File->Load Tags File". To jump to the definition for
a tag, highlight the word, then press Ctrl-D. NEdit 5.1 can read multiple tag files from
different directories. Setting the X resource nedit.tagFile to the name of a tag file
instructs NEdit to automatically load that tag file at startup time.
CAVEATS
Because ctags-universal is neither a preprocessor nor a compiler, use of preprocessor
macros can fool ctags-universal into either missing tags or improperly generating
inappropriate tags. Although ctags-universal has been designed to handle certain common
cases, this is the single biggest cause of reported problems. In particular, the use of
preprocessor constructs which alter the textual syntax of C can fool ctags-universal. You
can work around many such problems by using the -I option.
Note that since ctags-universal generates patterns for locating tags (see the --excmd
option), it is entirely possible that the wrong line may be found by your editor if there
exists another source line which is identical to the line containing the tag. The
following example demonstrates this condition:
int variable;
/* ... */
void foo(variable)
int variable;
{
/* ... */
}
Depending upon which editor you use and where in the code you happen to be, it is possible
that the search pattern may locate the local parameter declaration in foo() before it
finds the actual global variable definition, since the lines (and therefore their search
patterns are identical). This can be avoided by use of the --excmd=n option.
BUGS
ctags-universal has more options than ls(1).
When parsing a C++ member function definition (e.g. "className::function"),
ctags-universal cannot determine whether the scope specifier is a class name or a
namespace specifier and always lists it as a class name in the scope portion of the
extension fields. Also, if a C++ function is defined outside of the class declaration (the
usual case), the access specification (i.e. public, protected, or private) and
implementation information (e.g. virtual, pure virtual) contained in the function
declaration are not known when the tag is generated for the function definition. It will,
however be available for prototypes (e.g. "--c++-kinds=+p").
No qualified tags are generated for language objects inherited into a class.
ENVIRONMENT VARIABLES
CTAGS If this environment variable exists, it will be expected to contain a set of
default options which are read when ctags-universal starts, after the configuration
files listed in FILES, below, are read, but before any command line options are
read. Options appearing on the command line will override options specified in this
variable. Only options will be read from this variable. Note that all white space
in this variable is considered a separator, making it impossible to pass an option
parameter containing an embedded space. If this is a problem, use a configuration
file instead.
ETAGS Similar to the CTAGS variable above, this variable, if found, will be read when
etags starts. If this variable is not found, etags will try to use CTAGS instead.
TMPDIR On Unix-like hosts where mkstemp() is available, the value of this variable
specifies the directory in which to place temporary files. This can be useful if
the size of a temporary file becomes too large to fit on the partition holding the
default temporary directory defined at compilation time. ctags-universal creates
temporary files only if either (1) an emacs-style tag file is being generated, (2)
the tag file is being sent to standard output, or (3) the program was compiled to
use an internal sort algorithm to sort the tag files instead of the sort utility of
the operating system. If the sort utility of the operating system is being used,
it will generally observe this variable also. Note that if ctags-universal is
setuid, the value of TMPDIR will be ignored.
FILES
$HOME/.ctags.d/*.ctags
$HOMEDRIVE$HOMEPATH/ctags.d/*.ctags (on MSWindows only)
.ctags.d/*.ctags
ctags.d/*.ctags
If any of these configuration files exist, each will be expected to contain a set of
default options which are read in the order listed when ctags-universal starts, but
before the CTAGS environment variable is read or any command line options are read.
This makes it possible to set up personal or project-level defaults. It is possible to
compile ctags-universal to read an additional configuration file before any of those
shown above, which will be indicated if the output produced by the --version option
lists the "custom-conf" feature. Options appearing in the CTAGS environment variable or
on the command line will override options specified in these files. Only options will
be read from these files. Note that the option files are read in line-oriented mode in
which spaces are significant (since shell quoting is not possible) but spaces at the
beginning of a line are ignored. Each line of the file is read as one command line
parameter (as if it were quoted with single quotes). Therefore, use new lines to
indicate separate command-line arguments. A line starting with '#' is treated as a
comment.
*.ctags files in a directory are loaded in alphabetical order.
tags The default tag file created by ctags-universal.
TAGS The default tag file created by etags.
SEE ALSO
See ctags-optlib(7) for defining (or extending) a parser in a configuration file.
The official Universal-ctags web site at:
https://ctags.io/
Also ex(1), vi(1), elvis, or, better yet, vim, the official editor of ctags. For more
information on vim, see the VIM Pages web site at:
http://www.vim.org/
AUTHOR
Universal-ctags project https://ctags.io
Darren Hiebert <dhiebert@users.sourceforge.net> http://DarrenHiebert.com/
MOTIVATION
"Think ye at all times of rendering some service to every member of the human race."
"All effort and exertion put forth by man from the fullness of his heart is worship, if it
is prompted by the highest motives and the will to do service to humanity."
-- From the Baha'i Writings
CREDITS
This version of ctags-universal (Universal-ctags) derived from the repository, known as
fishman-ctags, started by Reza Jelveh.
Some parsers are taken from tagmanager of Geany (https://www.geany.org/) project.
The fishman-ctags was derived from Exuberant-ctags.
Exuberant-ctags was originally derived from and inspired by the ctags program by Steve
Kirkendall <kirkenda@cs.pdx.edu> that comes with the Elvis vi clone (though virtually none
of the original code remains).
Credit is also due Bram Moolenaar <Bram@vim.org>, the author of vim, who has devoted so
much of his time and energy both to developing the editor as a service to others, and to
helping the orphans of Uganda.
The section entitled "HOW TO USE WITH GNU EMACS" was shamelessly stolen from the info page
for GNU etags.