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ctags(1)                  BSD General Commands Manual                 ctags(1)


NAME

     ctags -- create a tags file


SYNOPSIS

     ctags [-BFadtuwvx] [-f tags_file] name ...


DESCRIPTION

     ctags makes a tags file for ex(1) from the specified C, Pascal, Fortran,
     YACC, lex, and lisp sources.  A tags file gives the locations of speci-
     fied objects in a group of files.  Each line of the tags file contains
     the object name, the file in which it is defined, and a search pattern
     for the object definition, separated by white-space.

     Using the tags file, ex(1) can quickly locate these object definitions.
     Depending upon the options provided to ctags, objects will consist of
     subroutines, typedefs, defines, structs, enums, and unions.

     -a      append to tags file.

     -B      use backward searching patterns (?...?).

     -d      create tags for #defines that don't take arguments; #defines that
             take arguments are tagged automatically.

     -F      use forward searching patterns (/.../) (the default).

     -f      Places the tag descriptions in a file called tags_file.  The
             default behavior is to place them in a file called tags.

     -t      create tags for typedefs, structs, unions, and enums.

     -u      update the specified files in the tags file, that is, all refer-
             ences to them are deleted, and the new values are appended to the
             file.  (Beware: this option is implemented in a way which is
             rather slow; it is usually faster to simply rebuild the tags
             file.)

     -v      An index of the form expected by vgrind(1) is produced on the
             standard output.  This listing contains the object name, file
             name, and page number (assuming 64-line pages).  Because the out-
             put will be sorted into lexicographic order, it may be desirable
             to run the output through sort(1).  Sample use:

                   ctags -v files | sort -f > index
                   vgrind -x index

     -w      suppress warning diagnostics.

     -x      ctags produces a list of object names, the line number and file
             name on which each is defined, as well as the text of that line
             and prints this on the standard output.  This is a simple func-
             tion index which can be printed out for reading off-line.

     Files whose names end in `.c' or `.h' are assumed to be C source files
     and are searched for C style routine and macro definitions.  Files whose
     names end in `.y' are assumed to be YACC source files.  Files whose names
     end in `.l' are assumed to be lisp files if their first non-blank charac-
     ter is `;', `(', or `[', otherwise, they are treated as lex files.  Other
     files are first examined to see if they contain any Pascal or Fortran
     routine definitions; if not, they are searched for C-style definitions.

     The tag main is treated specially in C programs.  The tag formed is cre-
     ated by prepending M to the name of the file, with the trailing `.c' and
     any leading pathname components removed.  This makes use of ctags practi-
     cal in directories with more than one program.

     Yacc and lex files each have a special tag.  Yyparse is the start of the
     second section of the yacc file, and yylex is the start of the second
     section of the lex file.


FILES

     tags     default output tags file


DIAGNOSTICS

     ctags exits with a value of 1 if an error occurred, 0 otherwise.  Dupli-
     cate objects are not considered to be errors.


SEE ALSO

     cc(1), ex(1), lex(1), sort(1), vgrind(1), vi(1), yacc(1)


BUGS

     Recognition of functions, subroutines, and procedures for FORTRAN and
     Pascal is done in a very simple-minded way.  No attempt is made to deal
     with block structure; if you have Pascal procedures with the same name in
     different blocks, you lose.  ctags doesn't understand about Pascal types.

     The method of deciding whether to look for C, Pascal, or FORTRAN func-
     tions is a hack.

     ctags relies on the input being well formed, so any syntactical errors
     will completely confuse it.  It also finds some legal syntax to be con-
     fusing; for example, because it doesn't understand #ifdef's (inciden-
     tally, that's a feature, not a bug), any code with unbalanced braces
     inside #ifdef's will cause it to become somewhat disoriented.  In a simi-
     lar fashion, multiple line changes within a definition will cause it to
     enter the last line of the object, rather than the first, as the search-
     ing pattern.  The last line of multiple line typedef's will similarly be
     noted.


HISTORY

     The ctags command appeared in 3.0BSD.

4th Berkeley Distribution        June 6, 1993        4th Berkeley Distribution

Mac OS X 10.7 - Generated Fri Nov 4 06:14:09 CDT 2011
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