CTAGS(1)                COMMAND REFERENCE                CTAGS(1)



NAME
     ctags - create a tags file

SYNOPSIS
     ctags [ -B ] [ -F ] [ -a ] [ -t ] [ -u ] [ -v ] [ -w ] [ -x
     ]
     filename ...

DESCRIPTION
     Ctags makes a tags file for ex(1) from the specified C,
     Pascal, and FORTRAN 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 blanks or tabs.  Using the tags file, the
     editting system ex can quickly find these object
     definitions.

     Files whose name ends in .c or .h or have no suffix are
     assumed to be C source files and are searched for C routine
     and macro definitions.  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 programs.  The tag
     formed is created by prepending M to the name of the file,
     with a trailing .c removed, if any, and leading pathname
     components also removed.  This makes use of ctags practical
     in directories with more than one program.

OPTIONS
     -a  Append to tags file.

     -t  Create tags for typedefs.

     -u  Causes the specified files to be updated 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 which is rather slow; it is
         usually faster to simply rebuild the tags file.)

     -v  An index of the form expected by vgrind (see CAVEATS) is
         produced on the standard output.  This listing contains
         the function name, filename, 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 (see EXAMPLES).

     -w  Suppresses warning diagnostics.



Printed 10/17/86                                                1

CTAGS(1)                COMMAND REFERENCE                CTAGS(1)



     -x  Ctags produces a list of object names, the line number
         and filename 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.

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

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

EXAMPLES
     This example produces a tags file for a program made up of
     the source files example.c and extras.c. The entries in the
     tags file will have backward search for patterns:



          ctags -B example.c extras.c


     Executing the command vi -t main will edit the file
     containing the routine main( ), and place the cursor at the
     definition of that routine by searching backwards.

     The following command set prints a sorted cross reference
     listing for the files using vgrind (see CAVEATS):



          ctags -v files | sort -f > index
          vgrind -x index


FILES
     tags                     Tags file for use with ex(1).

RETURN VALUE
     [NO_ERRS]      Command completed without error.

     [USAGE]        Incorrect command line syntax. Execution
                    terminated.

     [NP_WARN]      An error warranting a warning message
                    occurred. Execution continues.

     [P_WARN]       A system error occurred. Execution continues.
                    See intro(2) for more information on system
                    errors.

     [P_ERR]        A system error occurred. Execution
                    terminated.  See intro(2) for more
                    information on system errors.



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CTAGS(1)                COMMAND REFERENCE                CTAGS(1)



CAVEATS
     Recognition of functions, subroutines, and procedures for
     FORTRAN and Pascal is done in a very simple way.  No attempt
     is made to deal with block structure; if you have two Pascal
     procedures in different blocks with the same name, only the
     first is tagged.

     The method of deciding whether to look for C or Pascal and
     FORTRAN functions uses the prefix of the file, and may not
     always decide on the correct language.

     Does not process #ifdefs (used by the preprocessor).

     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.

     The -v option is supported for completeness. The utility
     vgrind may not be available on your system.

SEE ALSO
     cflow(1), cxref(1), ex(1), sort(1), vi(1).

































Printed 10/17/86                                                3

%%index%%
na:72,70;
sy:142,290;
de:432,1451;
op:1883,973;3000,478;
ex:3478,761;
fi:4239,119;
rv:4358,680;
ca:5182,900;
se:6082,175;
%%index%%000000000155