CTAGS(1) General Commands Manual CTAGS(1)
NAME
ctags – create a tags file
SYNOPSIS
ctags [-BFadtuwvx] [-f tags_file] 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.
-a append to tags file.
-B use backward searching patterns (?...?).
-d create tags for #defines that don't take arguments; #defines that
take arguments are tagged automatically.
-F use forward searching patterns (/.../) (the default).
-f Places the tag descriptions in a file called tags_file. The
default behavior 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). Because the output will
be sorted into lexicographic order, it may be desirable 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 function
index which can be printed out for reading off-line.
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; if not, they 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
DIAGNOSTICS
ctags exits with a value of 1 if an error occurred, 0 otherwise. Duplicate
objects are not considered to be errors.
SEE ALSO
cc(1), ex(1), lex(1), sort(1), vi(1), yacc(1)
BUGS
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 Pascal procedures with the same name in
different blocks, 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, so any syntactical errors will
completely confuse it. It also finds some legal syntax to be confusing;
for example, because 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.
HISTORY
The ctags command appeared in 3.0BSD.
BSD 4 June 6, 1993 BSD 4