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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



 NAME
      ctags - Generate tag files for source code



 SYNOPSIS
      ctags [options] [file(s)]

      etags [options] [file(s)]



 DESCRIPTION
      The ctags and etags programs (hereinafter collectively referred to as
      ctags, except where distinguished) generate an index (or "tag") file
      for a variety of language objects found in file(s).  This tag file
      allows these items to be quickly and easily located by a text editor
      or other utility. A "tag" signifies a language object for which an
      index entry is available (or, alternatively, the index entry created
      for that object).

      Alternatively, ctags can generate a cross reference file which lists,
      in human readable form, information about the various source objects
      found in a set of language 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. Those known
      about at the time of this release are:

          Vi(1) and its derivatives (e.g. Elvis, Vim, Vile, Lemmy), CRiSP,
          Emacs, FTE (Folding Text Editor), JED, jEdit, Mined, NEdit
          (Nirvana Edit), TSE (The SemWare Editor), UltraEdit, WorkSpace,
          X2, Zeus

      Ctags 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
      options.



 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
      display using the --list-maps option and may be changed using the
      --langmap option.  On platforms which support it, if the name of a



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



      file is not mapped to a language and the file is executable, the first
      line of the file is checked to see if the file is a "#!" script for a
      recognized language.

      By default, all other files names are ignored. This permits running
      ctags on all files in either a single directory (e.g. "ctags *"), or
      on all files in an entire source directory tree (e.g. "ctags -R"),
      since only those files whose names are mapped to languages will be
      scanned.

      [The reason that .h extensions are mapped to C++ files rather than C
      files is because it is common to use .h extensions in C++, and no harm
      results in treating them as C++ files.]



 OPTIONS
      Despite the wealth of available options, defaults are set so that
      ctags is most commonly executed without any options (e.g. "ctags *",
      or "ctags -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" and "=on" are considered
      synonyms for "=yes", and that "=0" and "=off" 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.


      -a   Equivalent to --append.


      -B   Use backward searching patterns (e.g. ?pattern?). [Ignored in



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



           etags mode]


      -e   Enable etags mode, which will create a tag file for use with the
           Emacs editor.  Alternatively, if ctags 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 tag file is written to standard output
           instead. Ctags 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
           -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]


      -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 a particular kinds of tags is
           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



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



           ".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 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 a 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, below). 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: 690 $")



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



           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.




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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



      -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 -x
           --c-kinds=f file), or generating a list of all externally visible
           global variables located in a source file (e.g. ctags -x
           --c-kinds=v --file-scope=no file). This option must appear before
           the first file name.


      --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 off 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, 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



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



           option parameter to protect the wildcards from being expanded by
           the shell before being passed to ctags; 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 --version 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 "EIFGEN", "SCCS", "RCS", and "CVS", which
           are names of directories for which it is generally not desirable
           to descend while processing the --recurse option.


      --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, below).
                    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.



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



                    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
           Specifies whether to include extra tag entries for certain kinds
           of information. 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 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. The meaning of each flag is as follows:


              f   Include an entry for the base file name of every source
                  file (e.g.  "example.c"), which addresses the first line
                  of the file.

              q   Include an extra class-qualified tag entry for each tag
                  which is a member of a class (for languages for which this
                  information is extracted; currently C++, Eiffel, and
                  Java). 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++, it is in the form
                  "class::member"; for Eiffel and Java, it is in the form
                  "class.member". 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.





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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



      --fields=[+|-]flags
           Specifies the available extension fields which are to be included
           in the entries of the tag file (see TAG FILE FORMAT, below, for
           more information). The parameter flags is a set of one-letter
           flags, each representing one type of extension field to include,
           with the following meanings (disabled by default unless
           indicated):


              a   Access (or export) of class members
              f   File-restricted scoping [enabled]
              i   Inheritance information
              k   Kind of tag as a single letter [enabled]
              K   Kind of tag as full name
              l   Language of source file containing tag
              m   Implementation information
              n   Line number of tag definition
              s   Scope of tag definition [enabled]
              S   Signature of routine (e.g. prototype or parameter list)
              z   Include the "kind:" key in kind field
              t   Type and name of a variable or typedef as "typeref:" field
                  [enabled]

           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 kinds explicitly
           listed in flags will be included in the output (i.e. overriding
           the default set). This option is ignored if the option --format=1
           has been specified. The default value of this option is fkst.


      --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.


      --filter[=yes|no]
           Causes ctags to 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 --sorted 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.



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



      --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 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 one 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]


      --help
           Prints to standard output a detailed usage description, and then
           exits.


      --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.


      --<LANG>-kinds=[+|-]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



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



           --list-kinds 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).

           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.


      --langdef=name
           Defines a new user-defined language, name, to be parsed with
           regular expressions. Once defined, name may be used in other
           options taking language names. The typical use of this option is
           to first define the language, then map file names to it using
           --langmap, then specify regular expressions using --regex-<LANG>
           to define how its tags are found.


      --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). You can determine if shell wildcards are
           available on your platform by examining the output of the
           --version 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, it will first be unmapped from any
           other languages.

           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



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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



           "--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 all 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
           extensions are tested before file name patterns when inferring
           the language of a file.


      --language-force=language
           By default, ctags 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 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
           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 complete list of the built-in language names.





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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



      --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 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.


      --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-kinds[=language|all]
           Lists the tag kinds recognized for either the specified language
           or all languages, and then exits. Each kind of tag recorded in
           the tag file is represented by a one-letter flag, which is also
           used to filter the tags placed into the output through use of the
           --<LANG>-kinds option. Note that some languages and/or tag kinds
           may be implemented using regular expressions and may not be
           available if regex support is not compiled into ctags (see the
           --regex-<LANG> option). Each kind listed is enabled unless
           followed by "[off]".


      --list-maps[=language|all]
           Lists the file extensions and file name patterns 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.




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                                 Version 5.8



      --list-languages
           Lists the names of the languages understood by ctags, and then
           exits.  These language names are case insensitive and may be used
           in the --language-force, --languages, --<LANG>-kinds, and
           --regex-<LANG> options.


      --options=file
           Read additional options from file. The file should contain one
           option per line. As a special case, if --options=NONE is
           specified as the first option on the command line, it will
           disable the automatic reading of any configuration options from
           either a file or the environment (see FILES).


      --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 -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]
           The /regexp/replacement/ pair define a regular expression
           replacement pattern, similar in style to sed substitution
           commands, with which to generate tags from source files mapped to
           the named language, <LANG>, (case-insensitive; either a built-in
           or user-defined language). The regular expression, regexp,
           defines an extended regular expression (roughly that used by
           egrep(1)), which is used to locate a single source line
           containing a tag and may specify tab characters using \t. When a
           matching line is found, a tag will be generated for the name
           defined by replacement, which generally will contain the special
           back-references \1 through \9 to refer to matching sub-expression
           groups within regexp. The '/' separator characters shown in the
           parameter to the option can actually be replaced by any
           character. Note that whichever separator character is used will
           have to be escaped with a backslash ('\') character wherever it
           is used in the parameter as something other than a separator. The
           regular expression defined by this option is added to the current
           list of regular expressions for the specified language unless the
           parameter is omitted, in which case the current list is cleared.

           Unless modified by flags, regexp is interpreted as a Posix



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                                 Version 5.8



           extended regular expression. The replacement should expand for
           all matching lines to a non-empty string of characters, or a
           warning message will be reported. An optional kind specifier for
           tags matching regexp may follow replacement, which will determine
           what kind of tag is reported in the "kind" extension field (see
           TAG FILE FORMAT, below). The full form of kind-spec is in the
           form of a single letter, a comma, a name (without spaces), a
           comma, a description, followed by a separator, which specify the
           short and long forms of the kind value and its textual
           description (displayed using --list-kinds). Either the kind name
           and/or the description may be omitted. If kind-spec is omitted,
           it defaults to "r,regex". Finally, flags are one or more single-
           letter characters having the following effect upon the
           interpretation of regexp:


              b   The pattern is interpreted as a Posix basic regular
                  expression.

              e   The pattern is interpreted as a Posix extended regular
                  expression (default).

              i   The regular expression is to be applied in a case-
                  insensitive manner.

           Note that this option is available only if ctags was compiled
           with support for regular expressions, which depends upon your
           platform. You can determine if support for regular expressions is
           compiled in by examining the output of the --version option,
           which will include "+regex" in the compiled feature list.

           For more information on the regular expressions used by ctags,
           see either the regex(5,7) man page, or the GNU info documentation
           for regex (e.g. "info regex").


      --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 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



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                                 Version 5.8



           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. 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. Normally, ctags 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 to standard output, and
           then exits. This is guaranteed to always contain the string
           "Exuberant Ctags".



 OPERATIONAL DETAILS
      As ctags 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 file name
      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). 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 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.



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                                 Version 5.8



      In general, ctags tries to be smart about conditional preprocessor
      directives. If a preprocessor conditional is encountered within a
      statement which defines a tag, ctags 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 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 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 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



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                                 Version 5.8



      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.





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                                 Version 5.8



      kind        Indicates the type, or kind, of tag. Its value is either
                  one of the corresponding one-letter flags described under
                  the various --<LANG>-kinds 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



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                                 Version 5.8



                  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, the press Ctrl-D. NEdit 5.1 can 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 is neither a preprocessor nor a compiler, use of
      preprocessor macros can fool ctags into either missing tags or
      improperly generating inappropriate tags. Although ctags 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. You can
      work around many such problems by using the -I option.

      Note that since ctags 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



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                                 Version 5.8



      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 has more options than ls(1).

      When parsing a C++ member function definition (e.g.
      "className::function"), ctags 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
              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,



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 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



              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 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 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 is
              setuid, the value of TMPDIR will be ignored.



 FILES
      /ctags.cnf (on MSDOS, MSWindows only)
      /etc/ctags.conf
      /usr/local/etc/ctags.conf
      $HOME/.ctags
      $HOME/ctags.cnf (on MSDOS, MSWindows only)
      .ctags
      ctags.cnf (on MSDOS, MSWindows only)
           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 starts, but before the CTAGS environment
           variable is read or any command line options are read. This makes
           it possible to set up site-wide, personal or project-level
           defaults. It is possible to compile ctags 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). 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.




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 CTAGS(1)                      Darren Hiebert                       CTAGS(1)
 Exuberant Ctags                                             Exuberant Ctags

                                 Version 5.8



      tags The default tag file created by ctags.

      TAGS The default tag file created by etags.


 SEE ALSO
      The official Exuberant Ctags web site at:

           http://ctags.sourceforge.net

      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
      Darren Hiebert <dhiebert at 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 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.





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