3 [![Build Status][13]][14]
5 [![Coverity Scan Build Status][17]][18]
7 ***WARNING: This project has moved to [https://git.yzena.com/][20] for [these
8 reasons][21], though GitHub will remain a mirror.***
10 This is an implementation of the [POSIX `bc` calculator][12] that implements
11 [GNU `bc`][1] extensions, as well as the period (`.`) extension for the BSD
14 For more information, see this `bc`'s full manual.
16 This `bc` also includes an implementation of `dc` in the same binary, accessible
17 via a symbolic link, which implements all FreeBSD and GNU extensions. (If a
18 standalone `dc` binary is desired, `bc` can be copied and renamed to `dc`.) The
19 `!` command is omitted; I believe this poses security concerns and that such
20 functionality is unnecessary.
22 For more information, see the `dc`'s full manual.
24 This `bc` is Free and Open Source Software (FOSS). It is offered under the BSD
25 2-clause License. Full license text may be found in the [`LICENSE.md`][4] file.
29 This `bc` only requires a C99-compatible compiler and a (mostly) POSIX
30 2008-compatible system with the XSI (X/Open System Interfaces) option group.
32 Since POSIX 2008 with XSI requires the existence of a C99 compiler as `c99`, any
33 POSIX and XSI-compatible system will have everything needed.
35 Systems that are known to work:
42 * Solaris* (as long as the Solaris version supports POSIX 2008)
45 Please submit bug reports if this `bc` does not build out of the box on any
46 system besides Windows. If Windows binaries are needed, they can be found at
51 This `bc` should build unmodified on any POSIX-compliant system.
53 For more complex build requirements than the ones below, see the
56 ### Pre-built Binaries
58 It is possible to download pre-compiled binaries for a wide list of platforms,
59 including Linux- and Windows-based systems, from [xstatic][6]. This link always
60 points to the latest release of `bc`.
64 For the default build with optimization, use the following commands in the root
74 To only build `bc`, use the following commands:
77 ./configure.sh --disable-dc
81 To only build `dc`, use the following commands:
84 ./configure.sh --disable-bc
90 For debug builds, use the following commands in the root directory:
99 To install, use the following command:
105 By default, `bc` and `dc` will be installed in `/usr/local`. For installing in
106 other locations, use the `PREFIX` environment variable when running
107 `configure.sh` or pass the `--prefix=<prefix>` option to `configure.sh`. See the
108 [build manual][5], or run `./configure.sh --help`, for more details.
110 ### Package and Distro Maintainers
112 #### Recommended Compiler
114 When I ran benchmarks with my `bc` compiled under `clang`, it performed much
115 better than when compiled under `gcc`. I recommend compiling this `bc` with
118 I also recommend building this `bc` with C11 if you can because `bc` will detect
119 a C11 compiler and add `_Noreturn` to any relevant function(s).
121 #### Recommended Optimizations
123 I wrote this `bc` with Separation of Concerns, which means that there are many
124 small functions that could be inlined. However, they are often called across
125 file boundaries, and the default optimizer can only look at the current file,
126 which means that they are not inlined.
128 Thus, because of the way this `bc` is built, it will automatically be slower
129 than other `bc` implementations when running scripts with no math. (My `bc`'s
130 math is *much* faster, so any non-trivial script should run faster in my `bc`.)
132 Some, or all, of the difference can be made up with the right optimizations. The
133 optimizations I recommend are:
136 2. `-flto` (link-time optimization)
140 Link-time optimization, in particular, speeds up the `bc` a lot. This is because
141 when link-time optimization is turned on, the optimizer can look across files
142 and inline *much* more heavily.
144 However, I recommend ***NOT*** using `-march=native`. Doing so will reduce this
145 `bc`'s performance, at least when building with link-time optimization. See the
146 [benchmarks][19] for more details.
148 #### Stripping Binaries
150 By default, non-debug binaries are stripped, but stripping can be disabled with
151 the `-T` option to `configure.sh`.
153 #### Using This `bc` as an Alternative
155 If this `bc` is packaged as an alternative to an already existing `bc` package,
156 it is possible to rename it in the build to prevent name collision. To prepend
157 to the name, just run the following:
160 EXECPREFIX=<some_prefix> ./configure.sh
163 To append to the name, just run the following:
166 EXECSUFFIX=<some_suffix> ./configure.sh
169 If a package maintainer wishes to add both a prefix and a suffix, that is
172 **Note**: The suggested name (and package name) when `bc` is not available is
175 #### Karatsuba Number
177 Package and distro maintainers have one tool at their disposal to build this
178 `bc` in the optimal configuration: `karatsuba.py`.
180 This script is not a compile-time or runtime prerequisite; it is for package and
181 distro maintainers to run once when a package is being created. It finds the
182 optimal Karatsuba number (see the [algorithms manual][7] for more information)
183 for the machine that it is running on.
185 The easiest way to run this script is with `make karatsuba`.
187 If desired, maintainers can also skip running this script because there is a
188 sane default for the Karatsuba number.
194 It is well-tested, fuzzed, and fully standards-compliant (though not certified)
195 with POSIX `bc`. The math has been tested with 40+ million random problems, so
196 it is as correct as I can make it.
198 This `bc` can be used as a drop-in replacement for any existing `bc`. This `bc`
199 is also compatible with MinGW toolchains, though history is not supported on
202 In addition, this `bc` is considered complete; i.e., there will be no more
203 releases with additional features. However, it *is* actively maintained, so if
204 any bugs are found, they will be fixed in new releases. Also, additional
205 translations will also be added as they are provided.
207 ## Comparison to GNU `bc`
209 This `bc` compares favorably to GNU `bc`.
211 * It has more extensions, which make this `bc` more useful for scripting.
212 * This `bc` is a bit more POSIX compliant.
213 * It has a much less buggy parser. The GNU `bc` will give parse errors for what
214 is actually valid `bc` code, or should be. For example, putting an `else` on
215 a new line after a brace can cause GNU `bc` to give a parse error.
216 * This `bc` has fewer crashes.
217 * GNU `bc` calculates the wrong number of significant digits for `length(x)`.
218 * GNU `bc` will sometimes print numbers incorrectly. For example, when running
219 it on the file `tests/bc/power.txt` in this repo, GNU `bc` gets all the right
220 answers, but it fails to wrap the numbers at the proper place when outputting
222 * This `bc` is faster. (See [Performance](#performance).)
226 Because this `bc` packs more than `1` decimal digit per hardware integer, this
227 `bc` is faster than GNU `bc` and can be *much* faster. Full benchmarks can be
228 found at [manuals/benchmarks.md][19].
230 There is one instance where this `bc` is slower: if scripts are light on math.
231 This is because this `bc`'s intepreter is slightly slower than GNU `bc`, but
232 that is because it is more robust. See the [benchmarks][19].
236 To see what algorithms this `bc` uses, see the [algorithms manual][7].
240 Currently, this `bc` only has support for English (and US English), French,
241 German, Portuguese, Dutch, Polish, Russian, Japanese, and Chinese locales.
242 Patches are welcome for translations; use the existing `*.msg` files in
243 `locales/` as a starting point.
245 In addition, patches for improvements are welcome; the last two messages in
246 Portuguese were made with Google Translate, and the Dutch, Polish, Russian,
247 Japanese, and Chinese locales were all generated with [DeepL][22].
249 The message files provided assume that locales apply to all regions where a
250 language is used, but this might not be true for, e.g., `fr_CA` and `fr_CH`.
251 Any corrections or a confirmation that the current texts are acceptable for
252 those regions would be appreciated, too.
256 Other projects based on this bc are:
258 * [busybox `bc`][8]. The busybox maintainers have made their own changes, so any
259 bugs in the busybox `bc` should be reported to them.
261 * [toybox `bc`][9]. The maintainer has also made his own changes, so bugs in the
262 toybox `bc` should be reported there.
264 * [FreeBSD `bc`][23]. While the `bc` in FreeBSD is kept up-to-date, it is better
265 to report bugs there, and the maintainers of the package will contact me if
270 This `bc` is written in pure ISO C99, using POSIX 2008 APIs.
274 This `bc` uses the commit message guidelines laid out in [this blog post][10].
276 ## Semantic Versioning
278 This `bc` uses [semantic versioning][11].
282 Items labeled with `(maintainer use only)` are not included in release source
287 .gitignore The git ignore file (maintainer use only).
288 .travis.yml The Travis CI file (maintainer use only).
289 codecov.yml The Codecov file (maintainer use only).
290 configure A symlink to configure.sh to make packaging easier.
291 configure.sh The configure script.
292 functions.sh A script with functions used by other scripts.
293 install.sh Install script.
294 karatsuba.py Script to find the optimal Karatsuba number.
295 LICENSE.md A Markdown form of the BSD 2-clause License.
296 link.sh A script to link dc to bc.
297 locale_install.sh A script to install locales, if desired.
298 locale_uninstall.sh A script to uninstall locales.
299 Makefile.in The Makefile template.
300 manpage.sh Script to generate man pages from markdown files.
301 NOTICE.md List of contributors and copyright owners.
302 RELEASE.md A checklist for making a release (maintainer use only).
303 release.sh A script to test for release (maintainer use only).
304 safe-install.sh Safe install script from musl libc.
308 gen The bc math library, help texts, and code to generate C source.
309 include All header files.
310 locales Locale files, in .msg format. Patches welcome for translations.
311 manuals Manuals for both programs.
315 [1]: https://www.gnu.org/software/bc/
317 [5]: ./manuals/build.md
318 [6]: https://pkg.musl.cc/bc/
319 [7]: ./manuals/algorithms.md
320 [8]: https://git.busybox.net/busybox/tree/miscutils/bc.c
321 [9]: https://github.com/landley/toybox/blob/master/toys/pending/bc.c
322 [10]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
323 [11]: http://semver.org/
324 [12]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html
325 [13]: https://travis-ci.com/gavinhoward/bc.svg?branch=master
326 [14]: https://travis-ci.com/gavinhoward/bc
327 [15]: https://codecov.io/gh/gavinhoward/bc/branch/master/graph/badge.svg
328 [16]: https://codecov.io/gh/gavinhoward/bc
329 [17]: https://img.shields.io/coverity/scan/16609.svg
330 [18]: https://scan.coverity.com/projects/gavinhoward-bc
331 [19]: ./manuals/benchmarks.md
332 [20]: https://git.yzena.com/gavin/bc
333 [21]: https://gavinhoward.com/2020/04/i-am-moving-away-from-github/
334 [22]: https://www.deepl.com/translator
335 [23]: https://github.com/freebsd/freebsd/tree/master/contrib/bc