cweb

CWEB(1)                     General Commands Manual                    CWEB(1)

NAME
       ctangle, cweave - translate CWEB to TeX

SYNOPSIS
       ctangle [options] webfile[.w] [{changefile[.ch]|-} [outfile[.c]]]
       cweave [options] webfile[.w] [{changefile[.ch]|-} [outfile[.tex]]]

DESCRIPTION
       The  ctangle  program converts a CWEB source document into a C/C++ pro-
       gram that may be compiled in the usual way.  The output  file  includes
       #line specifications so that debugging can be done in terms of the CWEB
       source file.

       The cweave program converts the same CWEB file into a TeX file that may
       be  formatted  and printed in the usual way.  It takes appropriate care
       of typographic details like page layout and  the  use  of  indentation,
       italics, boldface, etc., and it supplies extensive cross-index informa-
       tion that it gathers automatically.

       CWEB allows you to prepare a single document containing all the  infor-
       mation that is needed both to produce a compilable C/C++ program and to
       produce a well-formatted document describing the program in as much de-
       tail  as  the writer may desire.  The user of CWEB ought to be familiar
       with TeX as well as C/C++.

USAGE
       The command line should have one, two, or three names on it.  The first
       is  taken as the CWEB input file (and .w is added if there is no exten-
       sion).  If there is a second name, it is a  change  file  (and  .ch  is
       added  if  there  is no extension).  The change file overrides parts of
       the CWEB file, as described in the documentation.  If there is a  third
       name,  it overrides the default name of the output file, which is ordi-
       narily the same as the name of the input file (but on the  current  di-
       rectory)  with the extension .tex.  If you just want to change the out-
       put file name, but don't have a change file to apply, you can  use  `-'
       as the second argument.

DIFFERENCES TO ORIGINAL CWEB
       CWEBbin  tries hard to be a drop-in replacement for CWEB, so in general
       you should not notice any differences in invoking the programs  nor  in
       the resulting output.  There are, however, a few differences worth not-
       ing:

       o Options --help, --quiet, --verbose, --version, and flags -i, -o,  and
         +lX are new in CWEBbin and TeX Live.

       o Option  +lX  is  accompanied by several wrapper files for cwebmac.tex
         with translated captions for German (+ld), French (+lf), and  Italian
         (+li).

       o CWEB  in  TeX Live operates silently by default (as of 2019); use the
         --verbose option to get the original behavior.

       o File lookup with the environment variable CWEBINPUTS is  extended  to
         permit several, colon-separated, paths.

       o If  properly configured, the main programs ctangle and cweave are lo-
         calized with the "GNU gettext utilities".

OPTIONS
       Options on the command line may be either turned off with `-' (if  they
       are  on by default) or turned on with `+' (if they are off by default).
       In fact, the options are processed from left to right,  so  a  sequence
       like  --verbose -h will only show the banner line (+b) and the progress
       report (+p), but leave out the happy message (-h).

       The first batch of options are common to both ctangle and cweave:

       o +b: print banner line on terminal

       o +h: print success message on completion

       o +p: print progress report messages

       o +q/-q: shortcut for -bhp; also --quiet (default)

       o +v/-v: shortcut for +bhp; also --verbose

       o +s: print usage statistics

       o --help: display help message and exit

       o --version: output version information and exit

       There are six other options applicable to cweave only:

       o -e: do not enclose C/C++ material in \PB{...}

       o -f: do not force a newline after every C/C++ statement in output

       o -i: suppress indentation of parameter declarations

       o -o: suppress separation of declarations and statements

       o -x: omit indices, section names, table of contents

       o +lX/-lX: use macros for language X as of Xcwebmac.tex

ENVIRONMENT
       The environment variable CWEBINPUTS is used to  search  for  the  input
       files,  or the system default if CWEBINPUTS is not set.  See tex(1) for
       the details of the searching.

       If prepared for NLS support, ctangle and  cweave  use  the  environment
       variable  TEXMFLOCALEDIR  to  configure  the parent directory where the
       "GNU gettext utilities" search for translation catalogs.

       These variables are preconfigured in TeX Live's texmf.cnf.

FILES
       The location of the files mentioned below varies from system to system.
       Use the kpsewhich utility to find their locations.

       o cwebmac.tex:  The  default TeX macros \input in the first line of the
         cweave output file.

       o cwebman.tex: The  CWEB  user  manual,  available  in  PDF  from  CTAN
         (https://ctan.org/pkg/cweb).

SEE ALSO
       o The  CWEB  System of Structured Documentation: by Donald E. Knuth and
         Silvio Levy (hardcopy version of  cwebman.tex  and  the  source  code
         listings of common.w, ctangle.w, and cweave.w).

       o Literate Programming: by D. E. Knuth.

       o Weaving a Program: by Wayne Sewell.

       cweb(1), tex(1), cc(1)

AUTHORS
       Don Knuth wrote WEB for TeX and Pascal.
       Silvio Levy designed and developed CWEB by adapting the WEB conventions
       to C and by recoding everything in CWEB.  Knuth began  using  CWEB  and
       made  further  refinements.  Many other helpers are acknowledged in the
       CWEB manual.
       As of 2019, the CWEB system in TeX Live is based on the CWEBbin  exten-
       sion  that  collects ideas and improvements from numerous contributors;
       see the project page (https://github.com/ascherer/cwebbin).

Web2c 2019                     January 27, 2019                        CWEB(1)