DragonFly On-Line Manual Pages
CTAGS(1) DragonFly General Commands Manual CTAGS(1)
ctags -- create a tags file
ctags [-BFadtuwvx] [-f tagsfile] name ...
The ctags utility makes a tags file for ex(1) from the specified C, Pas-
cal, Fortran, yacc(1), lex(1), and Lisp sources. A tags file gives the
locations of specified 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.
The following options are available:
-B Use backward searching patterns (?...?).
-F Use forward searching patterns (/.../) (the default).
-a Append to tags file.
-d Create tags for #defines that do not take arguments; #defines
that take arguments are tagged automatically.
-f Place 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(1) 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(1)
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
The tag ``main'' is treated specially in C programs. The tag formed is
created by prepending `M' to the name of the file, with the trailing .c
and any leading pathname components removed. This makes use of ctags
practical in directories with more than one program.
yacc(1) and lex(1) files each have a special tag. ``yyparse'' is the
start of the second section of the yacc(1) file, and ``yylex'' is the
start of the second section of the lex(1) file.
tags default output tags file
The ctags utility exits with a value of 1 if an error occurred, 0 other-
wise. Duplicate objects are not considered errors.
The ctags utility appeared in 3.0BSD.
Recognition of functions, subroutines and procedures for Fortran and Pas-
cal is done in 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. The ctags utility does not understand about
The method of deciding whether to look for C, Pascal or Fortran functions
is a hack.
The ctags utility relies on the input being well formed, and any syntac-
tical errors will completely confuse it. It also finds some legal syntax
confusing; for example, since it does not understand #ifdef's (inciden-
tally, that is 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
DragonFly 4.1 June 6, 1993 DragonFly 4.1