CTAGS(1HAS) User Commands CTAGS(1HAS)

NAME

ctags - create a tags file for use with ex and vi

SYNOPSIS

/usr/bin/ctags [-aBFtuvwx] [-f tagsfile] file...


/usr/xpg4/bin/ctags [-aBFuvwx] [-f tagsfile] file...

DESCRIPTION

The ctags utility makes a tags file for ex(1) from the specified C,
C++, Pascal, FORTRAN, yacc(1), and lex(1) sources. A tags file gives
the locations of specified objects (in this case functions and
typedefs) in a group of files. Each line of the tags file contains
the object name, the file in which it is defined, and an address
specification for the object definition. Functions are searched with
a pattern, typedefs with a line number. Specifiers are given in
separate fields on the line, separated by SPACE or TAB characters.
Using the tags file, ex can quickly find these objects' definitions.

Normally, ctags places the tag descriptions in a file called tags;
this may be overridden with the -f option.

Files with names ending in .c or .h are assumed to be either C or C++
source files and are searched for C/C++ routine and macro
definitions. Files with names ending in .cc, .C, or .cxx are assumed
to be C++ source files. Files with names ending in .y are assumed to
be yacc source files. Files with names ending in .l are assumed to
be lex files. Others are first examined to see if they contain any
Pascal or FORTRAN routine definitions; if not, they are processed
again looking for C definitions.

The tag main is treated specially in C or C++ programs. The tag
formed is created by prepending M to file, with a trailing .c, .cc,
.C, or .cxx removed, if any, and leading path name components also
removed. This makes use of ctags practical in directories with more
than one program.

OPTIONS

The precedence of the options that pertain to printing is -x, -v,
then the remaining options. The following options are supported:

-a
Appends output to an existing tags file.


-B
Uses backward searching patterns (?...?).


-f tagsfile
Places the tag descriptions in a file called tagsfile
instead of tags.


-F
Uses forward searching patterns (/.../) (default).


-t
Creates tags for typedefs. /usr/xpg4/bin/ctags creates
tags for typedefs by default.


-u
Updates the specified files in tags, 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 that is rather slow; it is
usually faster to simply rebuild the tags file.


-v
Produces on the standard output an index listing the
function 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 -f.


-w
Suppresses warning diagnostics.


-x
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.

OPERANDS

The following file operands are supported:

file.c
Files with basenames ending with the .c suffix are
treated as C-language source code.


file.h
Files with basenames ending with the .h suffix are
treated as C-language source code.


file.f
Files with basenames ending with the .f suffix are
treated as FORTRAN-language source code.

USAGE

The -v option is mainly used with vgrind which will be part of the
optional BSD Compatibility Package.

EXAMPLES

Example 1: Producing entries in alphabetical order

Using ctags with the -v option produces entries in an order which may
not always be appropriate for vgrind. To produce results in
alphabetical order, you may want to run the output through sort -f.


example% ctags -v filename.c filename.h | sort -f > index
example% vgrind -x index

Example 2: Building a tags file

To build a tags file for C sources in a directory hierarchy rooted at
sourcedir, first create an empty tags file, and then run find(1)


example% cd sourcedir ; rm -f tags ; touch tags
example% find . \( -name SCCS -prune -name \\
'*.c' -o -name '*.h' \) -exec ctags -u {} \;


Notice that spaces must be entered exactly as shown.

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment
variables that affect the execution of ctags: LANG, LC_ALL,
LC_COLLATE, LC_CTYPE, LC_MESSAGES, and NLSPATH.

EXIT STATUS

The following exit values are returned:

0
Successful completion.


>0
An error occurred.

FILES

tags
output tags file

ATTRIBUTES

/usr/xpg4/bin/ctags

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

SEE ALSO

ex(1), lex(1), vgrind(1), vi(1), yacc(1), attributes(7), environ(7),
standards(7)

NOTES

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 method of deciding whether to look for C or Pascal and FORTRAN
functions is a hack.

The ctags utility does not know about #ifdefs.

The ctags utility should know about Pascal types. Relies on the input
being well formed to detect typedefs. Use of -tx shows only the last
line of typedefs.

March 18, 1997 CTAGS(1HAS)