NAME

ctags − create a tags file

SYNOPSIS

ctags [ −u ] [ −v ] [ −w ] [ −x ] name ... 

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) in a group of files. Each line of the tags file contains the function name, the file in which it is defined, and a scanning pattern used to find the function definition.  These are given in separate fields on the line, separated by blanks or tabs. Using the tags file, ex can quickly find these function definitions. 

If the −x flag is given, ctags produces a list of function 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. 

If the −v flag is given, an index of the form expected by vgrind(1) is produced on the standard output. This listing contains 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.  Sample use:

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

Files whose name ends in .c or .h 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. 

Other options are:

−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. 

FILES

tagsoutput tags file

SEE ALSO

ex(1), vi(1)

AUTHOR

Ken Arnold; FORTRAN added by Jim Kleckner; Bill Joy added Pascal and −x, replacing cxref. 

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. 

th Berkeley Distribution  —  4/1/81