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 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 whitespace.
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 options are as follows:
-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 tagsfile
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.
tags default output tags file
ctags exits with a value of 1 if an error occurred, 0 otherwise. Duplicate
objects are not considered errors.
ex(1), vi(1)
The ctags command appeared in 3.0BSD.
Recognition of functions, subroutines, and procedures for
FORTRAN and
Pascal is done in a very simple-minded 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.
OpenBSD 3.6 June 6, 1993
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