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
#definesthat don't take arguments;#definesthat 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.
-xctagsproduces 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
DIAGNOSTICS
Ctags exits with a value of 1 if an error
occurred, 0 otherwise. Duplicate objects are not considered errors.
SEE ALSO
BUGS
Recognition of functions,
subroutines and procedures
for FORTRAN and Pascal is done is 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.
HISTORY
The ctags command appeared in
3.0BSD.