CTWILL(1) General Commands Manual CTWILL(1)
NAME
ctwill, ctwill-proofsort, ctwill-refsort, ctwill-twinx - translate CWEB
to TeX with mini-indexes
SYNOPSIS
ctwill [options] webfile[.w] [{changefile[.ch]|-} [outfile[.tex]]]
( ctwill-proofsort < texfile.tex ) 1<> texfile.tex
ctwill-refsort < indexfile.ref > indexfile.sref
ctwill-twinx outfile.tex [outfile.tex ...] > index.tex
DESCRIPTION
The ctwill program converts a CWEB source document 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 informa-
tion 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 ordinarily the
same as the name of the input file (but on the current directory) with
the extension .tex. If you just want to change the output file name,
but don’t have a change file to apply, you can use `-' as the second ar-
gument.
ctwill is exactly like cweave except that it produces much better docu-
mentation, for which you must work much harder. You should run ctwill
twice, once to prime the pump and once to get decent answers. Moreover,
you must run the output twice through TeX.
After tex foo you will have output that looks like final pages except
that the entries of mini-indexes won’t be alphabetized. The first run
produces a weird file called foo.ref. Say ctwill-refsort < foo.ref >
foo.sref and then another tex foo will produce alphabetized output.
The ctwill-twinx program compiles a master index for a set of related
programs that have been processed by ctwill (not by cweave, mind you!).
The individual programs should define their names with a line of the
form \def\title{NAME}. For your convenience, ctwill-twinx grabs the
first “word” in \title and turns it into uppercase form. You should
adapt file twinx-startup.tex for the first page of the master index.
The mini-indexes list identifiers that are used but not defined on each
two-page spread. At the end of each section, ctwill gives TeX a list of
identifiers used in that section and information about where they are
defined.
The current meaning of every identifier is initially \uninitialized.
Then ctwill reads the .aux file for your job, if any.
Before reading the .aux file, ctwill actually looks for a file called
system.bux, which will be read if present. And after foo.aux, a third
possibility is foo.bux. The general convention is to put definitions of
system procedures such as printf into system.bux, and to put definitions
found in specifically foo-ish header files into foo.bux. Like the .aux
files, .bux files should contain only @$ specifications.
The meaning specified by @$...@> generally has four components: an iden-
tifier (followed by space), a program name (enclosed in braces), a sec-
tion number (followed by space), and a TeX part.
A special proofmode is provided so that you can check ctwill’s conclu-
sions about cross-references. Run ctwill with the flag +P, and TeX will
produce a specially formatted document with mini-indexes for each sec-
tion, so that you can check that your specifications are correct.
This proofmode format is used in conjunction with pdfctproofmac.tex that
creates active hyperlinks in PDF and HINT output. You can use ctwill-
proofsort to get the index entries in alphabetical order; just invoke
( ctwill-proofsort < texfile.tex ) 1<> texfile.tex
after invoking ctwill (twice), but before invoking TeX (once).
More details how to use ctwill can be found in the first sections of its
source code, respectively the change file cweav-twill.ch applicable to
the cweave.w source. A complete example with all bells and whistles is
described in Mini-Indexes for Literate Programs, pages 225–245 of
Knuth’s Digital Typography (CSLI, 1999).
DIFFERENCES TO ORIGINAL CTWILL
The present incarnation of ctwill and its utilities tries hard to be a
drop-in replacement for the original package. There are, however, a few
differences worth noting:
• This version is based on the most recent version of CWEB (4.11).
• In TeX Live the utility programs are prefixed with ctwill- and the
macro files with ct for technical reasons.
• Options --help, --quiet, --verbose, --version, and flags +c, -i, -o,
and +lX are new in CWEBbin and TeX Live.
• Option +lX is accompanied by example wrapper files for ctwimac.tex and
ctproofmac.tex with translated captions for German (+ld).
• Option +lX is also accompanied by an extended pdfctwimac.tex for pro-
duction of PDF and HINT output with active hyperlinks (+lpdf).
• ctwill in TeX Live operates silently by default; use the --verbose op-
tion to get the original behavior.
• File lookup with the environment variable CWEBINPUTS is extended to
permit several, colon-separated, paths; see ENVIRONMENT below.
• If properly configured, the main program ctwill is localized 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).
• +b: print banner line on terminal
• +h: print success message on completion
• +p: print progress report messages
• +q/-q: shortcut for -bhp; also --quiet (default)
• +v/-v: shortcut for +bhp; also --verbose
• +c: check temporary output for changes
• -e: do not enclose C/C++ material in \PB{...}
• -f: do not force a newline after every C/C++ statement in output
• -F: do not force a compound statement to start on a new line
• -i: suppress indentation of parameter declarations
• -o: suppress separation of declarations and statements
• -x: omit indices, section names, table of contents
• +P: \input ctproofmac.tex instead of ctwimac.tex
• +lX/-lX: use macros for language X as of X{ctwimac|ctproofmac}.tex
• +s: print usage statistics
• +t: treat typename in a template like typedef
• --help: display help message and exit
• --version: output version information and exit
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. To avoid conflicts with other programs
that also use the CWEBINPUTS environment, you can be more specific and
use CWEBINPUTS_cweb for special requirements in CWEB.
If prepared for NLS support, ctwill like ctangle and cweave uses the en-
vironment 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.
• ctwimac.tex: The default TeX macros \input in the first line of the
output file.
• ctproofmac.tex: If ctwill is invoked with the +P option, it will
change the first line of the output file to \input ctproofmac.tex.
In both cases you can request some prefix X with the +lX option, e.g.,
+ld will \input dctwimac.tex and +Pld will \input dctproofmac.tex. A
special application is the use of option +lpdf that will \input
pdfctwimac.tex or \input pdfctproofmac.tex for production of PDF and
HINT output with active hyperlinks.
• webfile.bux: Reference definitions to resolve from other modules.
• system.bux: Reference definitions to resolve from C/C++ standard li-
brary header files like <stdio.h>.
Other auxiliary files with references are created automatically by
ctwill and the actual index files are created by TeX.
• cwebman.tex: The CWEB user manual, available in PDF from ]8;;https://ctan.org/pkg/cweb\CTAN]8;;\.
SEE ALSO
• The CWEB System of Structured Documentation: by Donald E. Knuth and
Silvio Levy (hardcopy version of cwebman.tex and the source code list-
ings of common.w, ctangle.w, and cweave.w).
• Digital Typography: by D. E. Knuth (CSLI, 1999).
• Literate Programming: by D. E. Knuth (CSLI, 1992).
• Weaving a Program: by Wayne Sewell.
cweb(1), tex(1), cc(1)
AUTHORS
Don Knuth wrote ctwill based on cweave by Silvio Levy and Knuth.
Contemporary development on https://github.com/ascherer/cwebbin.
Web2c 2025/dev March 10, 2024 CTWILL(1)
Generated by dwww version 1.16 on Tue Dec 16 06:00:35 CET 2025.