create a tags
utility makes a
from the specified C, Pascal, Fortran,
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
can quickly locate these object definitions. Depending upon the options
, 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
Files whose names end in .c
are assumed to be C source files and are
searched for C style routine and macro definitions. Files whose names end in
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 “
” is treated specially in C
programs. The tag formed is created by prepending
’ to the name of the file, with the
and any leading pathname
components removed. This makes use of
practical in directories with more than one program.
files each have a special tag. “
is the start of the second section of the
file, and “
” is the start of the
second section of the
- default output tags file
utility exits with a value of 1 if
an error occurred, 0 otherwise. Duplicate objects are not considered errors.
option is a no-op for compatibility
with previous versions of
not create tags for typedefs, enums, structs and unions by default.
utility conforms to
IEEE Std 1003.1-2001
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
utility does not
understand about Pascal types.
The method of deciding whether to look for C, Pascal or Fortran functions is a
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
's (incidentally, that is a feature, not a bug),
any code with unbalanced braces inside
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
's will similarly be noted.