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CTAGS(1)		FreeBSD	General	Commands Manual		      CTAGS(1)

     ctags -- create a tags file

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

     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, type-
     defs, defines, structs, enums and unions.

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

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

     -a	     append to tags file.

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

     -f	     Places the	tag descriptions in a file called tagsfile.  The
	     default behaviour 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

     -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).  Since the	output
	     will be sorted into lexicographic order, it may be	desired	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 index
	     which can be printed out as an off-line readable function index.

     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 character
     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, and, if not, 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.

     tags  default output tags file

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

     ex(1), vi(1)

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

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

     Ctags relies on the input being well formed, and any syntactical errors
     will completely confuse it.  It also finds	some legal syntax confusing;
     for example, since	it doesn't understand #ifdef's (incidentally, that's a
     feature, not a bug), any code with	unbalanced braces inside #ifdef's will
     cause it to become	somewhat disoriented.  In a similar fashion, multiple
     line changes within a definition will cause it to enter the last line of
     the object, rather	than the first,	as the searching pattern.  The last
     line of multiple line typedef's will similarly be noted.

     The ctags command appeared	in 3.0BSD.

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


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