NAME
ctags —
create a tags file
SYNOPSIS
ctags |
[-BFadtuwvx]
[-f
tagsfile] 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
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.
-
-
- -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 references 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). 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 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 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
EXIT STATUS
The
ctags utility exits 0 on success, and >0 if
an error occurs. Duplicate objects are not considered errors.
SEE ALSO
ex(1),
vi(1)
HISTORY
The
ctags command appeared in
3.0BSD.
BUGS
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.
ctags doesn't understand about Pascal types.
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.