||FreeBSD General Commands Manual
create a tags file
tagsfile] file ...
ctags utility makes a tags
the specified C, Pascal, Fortran,
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,
quickly locate these object definitions. Depending upon the options provided
ctags, objects will consist of subroutines,
typedefs, defines, structs, enums and unions.
The following options are available:
- Use backward searching patterns (
- Use forward searching patterns (
- Do not create tags for typedefs, structs, unions, and enums.
- Append to tags file.
- Create tags for
#defines that do not take
#defines that take arguments are tagged
- Place the tag descriptions in a file called
tagsfile. The default behaviour is to place them in
a file called tags.
- 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
- An index of the form expected by
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
ctags -v files | sort -f > index
vgrind -x index
- Suppress warning diagnostics.
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
source files. Files whose names end in .l are
assumed to be Lisp files if their first non-blank character is
[’, otherwise, they are treated as
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.
files each have a special tag.
yyparse” is the start of the second
section of the
file, and “
yylex” is the start of the
second section of the
- default output tags file
ctags utility exits with a value of 1 if an error
occurred, 0 otherwise. Duplicate objects are not considered errors.
-t option is a no-op for compatibility with previous
ctags that did not create tags for
typedefs, enums, structs and unions by default.
ctags utility conforms to IEEE Std
ctags utility appeared in
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.
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
#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.
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