CTAGS(1)                                                              CTAGS(1)


NAME
     ctags - create a tags file

SYNOPSIS
     ctags [ -BFatuwvx ] [ -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 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, ex can quickly find these objects
     definitions.

     If the -x flag is given, 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.

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

     Files whose names end in .c or .h are assumed to be C source files and
     are searched for C 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 either lisp files if their first non-blank character is
     `;', `(', or `[', or lex files otherwise.  Other files are first examined
     to see if they contain any Pascal or Fortran routine definitions; if not,
     they are processed again looking for C definitions.

     Other options are:

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

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

     -a   append to tags file.  Since ex and vi use a binary search to locate
          tags, the resulting tags file should be sorted using sort(1).

     -t   create tags for typedefs.

     -v   Produce on the standard output an index of the form expected by
          vgrind(1).  This listing contains the function name, file name, and
          page number (assuming 64 line pages).

     -w   suppressing warning diagnostics.


     -u   causing 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.)

     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.

EXIT STATUS
     ctags exits with a value of greater than zero if an error occurs or a
     value of zero if successful completion results.  ctags writes to standard
     error with its diagnostic messages.  ctags writes to standard output with
     information resulting in the successful execution of its options and
     input.

FILES
     tags      output tags file

SEE ALSO
     ex(1), vi(1)

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.

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

     Does not know about #ifdefs.

     Should know about Pascal types.

     Use of -tx shows only the last line of typedefs.  Relies on the input
     being well formed to detect typedefs.  Typedefs are only partly
     understood.  typedef const unsigned short int Z; generates output which
     claims unsigned , short, int , and Z are all typedefs.


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