CTAGS(1) BSD Reference 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 de-
fault 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.
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 2