ctags
— create a
tags file
ctags |
[-BFTaduwvx ] [-f
tagsfile] file ... |
The ctags
utility makes a
tags file for
ex(1) from
the specified C, Pascal, 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).
-T
- Do not create tags for typedefs, structs, unions, and enums.
-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. If
tagsfile is “-”, the tags will be
written to standard output instead.
-u
- Update the specified files in the tags file, that
is, all references to them are deleted, and the new values are appended to
the file. This is ignored if the tags file does not exist or is not a
regular file (e.g.
-f
- was used to write to
standard output).
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). 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
definitions.
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.
The
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 otherwise. Duplicate objects are not considered
errors.
The -t
option is a no-op for compatibility
with previous versions of ctags
that did not create
tags for typedefs, enums, structs and unions by default.
The ctags
utility conforms to
IEEE Std 1003.1-2001 (“POSIX.1”).
The ctags
utility appeared in
3.0BSD.
Recognition of functions, subroutines and procedures for Fortran
and Pascal 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 Pascal types.
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 syntactical errors will completely confuse it. It
also finds some legal syntax confusing; for example, since it does not
understand #ifdef
's (incidentally, that is 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.