ctags(1)						      General Commands Manual							  ctags(1)

NAME

       ctags - create a tags file

SYNOPSIS

       files ...

DESCRIPTION

       makes  a  tags  file  for  ex(1) (or vi(1)) from the specified C, Pascal and FORTRAN sources.  A tags file gives the locations of specified
       objects (for C, functions, macros with argments, and typedefs; Pascal, procedures, programs and functions; FORTRAN,  subroutines,  programs
       and  functions)	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.  Output is sorted in ascending collation order (see Environment  Variables  below).   All  objects
       except C typedefs are searched with a pattern, typedefs with a line number.  Specifiers are given in separate fields on the line, separated
       by spaces or tabs.  Using the tags file, can quickly find these objects' definitions.

	      Cause   to print a simple function index.  This is done by assembling a list of function names, file names on which each function is
		      defined, the line numbers where each function name occurs, and the text of each line.  The list is then printed on the stan-
		      dard output.  No tags file is created or changed.

	      Produce a page index on the standard output.
		      This listing contains the function name, file name, and page number within  that	file  (assuming  56-line  pages  to  match
		      pr(1)).

       Files  whose name ends in or are assumed to be C source files and are searched for C routine and macro definitions.  Others are first exam-
       ined to see if they contain any Pascal or FORTRAN routine definitions; if not, they are processed again looking for C definitions.

       Other options are:

	      Use forward searching patterns
		      (default).

	      Use backward searching patterns

	      Add the information from the files to the
		      tags file.  Unlike re-building the tags file from the original files, this can cause the same symbol to be entered twice	in
		      the tags file.  This option should be used with caution and then only in very special circumstances.

	      Create tags for typedefs.

	      Suppress warning diagnostics.

	      Update the specified files in
		      tags;  that  is,	all references to those files are deleted, and the new values are added to the file as in above.  (Beware:
		      this option is implemented in a way which is rather slow; it is usually faster to simply rebuild the tags file.)

       The tag is treated specially in C programs.  The tag formed is created by adding to the beginning of name of the file,  with  any  trailing
       removed, and leading pathname components also removed.  This makes use of practical in directories with more than one program.

EXTERNAL INFLUENCES

   Environment Variables
       determines the order in which the output is sorted.

       determines the interpretation of the single- and/or multi-byte characters within comments and string literals.

       If  or  is  not specified in the environment or is set to the empty string, the value of is used as a default for each unspecified or empty
       variable.  If is not specified or is set to the empty string, a default of ``C'' (see lang(5)) is used instead of If any  internationaliza-
       tion variable contains an invalid setting, behaves as if all internationalization variables are set to ``C''.  See environ(5).

   International Code Set Support
       Single- and multi-byte character code sets are supported with the exception that multi-byte character file names are not supported.

DIAGNOSTICS

       An attempt to get additional heap space failed;
	      the sort could not be performed.

       The tags file may be incorrect.

	      A character was found unexpectedly in the first column.  This can lead to incorrect entries in the tags file.

       The same name was detected twice in the same file.
	      A tags entry was made only for the first name found.

       The same name was detected in two different files.
	      A tags entry was made only for the first name found.

EXAMPLES

       Create a tags file named in the current directory for all C source files and all header files in the current directory:

       Once the tags file exists in the current directory, it can be used with commands that support tag files (such as (see vi(1)).

       Use the tags file with to edit a particular function located in one of the source files:

       While editing a C source file using use the tag command to edit function

       Use to find in file

       While using find in file (does not have to be the file currently being edited):

WARNINGS

       Recognition  of and for FORTRAN and Pascal is done in a very simple way.  No attempt is made to deal with block structure; if there are two
       Pascal procedures in different blocks with the same name, a warning message is generated.

       The method of deciding whether to look for C or Pascal and FORTRAN functions is an approximation, and can be fooled by unusual programs.

       does not know about and Pascal types.

       It relies on the input being well formed to detect typedefs.

       Use of shows only the last line of typedefs.

       is naive about tags files with several identical tags; it simply chooses the first entry its (non-linear) search finds with that tag.  Such
       files can be created with either the or options or by editing a tags file.

       If more than one (function) definition appears on a single line, only the first definition is indexed.

AUTHOR

       was developed by the University of California, Berkeley.

FILES

       output tags file
       temporary file used by

SEE ALSO

       ex(1), vi(1).

STANDARDS CONFORMANCE

																	  ctags(1)