3 [![Coverity Scan Build Status][17]][18]
5 ***WARNING: This project has moved to [https://git.yzena.com/][20] for [these
6 reasons][21], though GitHub will remain a mirror.***
8 This is an implementation of the [POSIX `bc` calculator][12] that implements
9 [GNU `bc`][1] extensions, as well as the period (`.`) extension for the BSD
12 For more information, see this `bc`'s full manual.
14 This `bc` also includes an implementation of `dc` in the same binary, accessible
15 via a symbolic link, which implements all FreeBSD and GNU extensions. (If a
16 standalone `dc` binary is desired, `bc` can be copied and renamed to `dc`.) The
17 `!` command is omitted; I believe this poses security concerns and that such
18 functionality is unnecessary.
20 For more information, see the `dc`'s full manual.
22 This `bc` is Free and Open Source Software (FOSS). It is offered under the BSD
23 2-clause License. Full license text may be found in the [`LICENSE.md`][4] file.
27 This `bc` only requires a C99-compatible compiler and a (mostly) POSIX
28 2008-compatible system with the XSI (X/Open System Interfaces) option group.
30 Since POSIX 2008 with XSI requires the existence of a C99 compiler as `c99`, any
31 POSIX and XSI-compatible system will have everything needed.
33 Systems that are known to work:
40 * Solaris* (as long as the Solaris version supports POSIX 2008)
42 * HP-UX* (except for history)
44 Please submit bug reports if this `bc` does not build out of the box on any
45 system besides Windows. If Windows binaries are needed, they can be found at
50 This `bc` should build unmodified on any POSIX-compliant system.
52 For more complex build requirements than the ones below, see the
55 ### Pre-built Binaries
57 It is possible to download pre-compiled binaries for a wide list of platforms,
58 including Linux- and Windows-based systems, from [xstatic][6]. This link always
59 points to the latest release of `bc`.
63 For the default build with optimization, use the following commands in the root
73 To only build `bc`, use the following commands:
76 ./configure.sh --disable-dc
80 To only build `dc`, use the following commands:
83 ./configure.sh --disable-bc
89 For debug builds, use the following commands in the root directory:
98 To install, use the following command:
104 By default, `bc` and `dc` will be installed in `/usr/local`. For installing in
105 other locations, use the `PREFIX` environment variable when running
106 `configure.sh` or pass the `--prefix=<prefix>` option to `configure.sh`. See the
107 [build manual][5], or run `./configure.sh --help`, for more details.
111 This `bc` does provide a way to build a math library with C bindings. This is
112 done by the `-a` or `--library` options to `configure.sh`:
118 When building the library, the executables are not built. For more information,
119 see the [build manual][5].
121 The library API can be found in [`manuals/bcl.3.md`][26] or `man bcl` once the
122 library is installed.
124 The library is built as `bin/libbcl.a`.
126 ### Package and Distro Maintainers
128 #### Recommended Compiler
130 When I ran benchmarks with my `bc` compiled under `clang`, it performed much
131 better than when compiled under `gcc`. I recommend compiling this `bc` with
134 I also recommend building this `bc` with C11 if you can because `bc` will detect
135 a C11 compiler and add `_Noreturn` to any relevant function(s).
137 #### Recommended Optimizations
139 I wrote this `bc` with Separation of Concerns, which means that there are many
140 small functions that could be inlined. However, they are often called across
141 file boundaries, and the default optimizer can only look at the current file,
142 which means that they are not inlined.
144 Thus, because of the way this `bc` is built, it will automatically be slower
145 than other `bc` implementations when running scripts with no math. (My `bc`'s
146 math is *much* faster, so any non-trivial script should run faster in my `bc`.)
148 Some, or all, of the difference can be made up with the right optimizations. The
149 optimizations I recommend are:
152 2. `-flto` (link-time optimization)
156 Link-time optimization, in particular, speeds up the `bc` a lot. This is because
157 when link-time optimization is turned on, the optimizer can look across files
158 and inline *much* more heavily.
160 However, I recommend ***NOT*** using `-march=native`. Doing so will reduce this
161 `bc`'s performance, at least when building with link-time optimization. See the
162 [benchmarks][19] for more details.
164 #### Stripping Binaries
166 By default, non-debug binaries are stripped, but stripping can be disabled with
167 the `-T` option to `configure.sh`.
169 #### Using This `bc` as an Alternative
171 If this `bc` is packaged as an alternative to an already existing `bc` package,
172 it is possible to rename it in the build to prevent name collision. To prepend
173 to the name, just run the following:
176 EXECPREFIX=<some_prefix> ./configure.sh
179 To append to the name, just run the following:
182 EXECSUFFIX=<some_suffix> ./configure.sh
185 If a package maintainer wishes to add both a prefix and a suffix, that is
188 **Note**: The suggested name (and package name) when `bc` is not available is
191 #### Karatsuba Number
193 Package and distro maintainers have one tool at their disposal to build this
194 `bc` in the optimal configuration: `karatsuba.py`.
196 This script is not a compile-time or runtime prerequisite; it is for package and
197 distro maintainers to run once when a package is being created. It finds the
198 optimal Karatsuba number (see the [algorithms manual][7] for more information)
199 for the machine that it is running on.
201 The easiest way to run this script is with `make karatsuba`.
203 If desired, maintainers can also skip running this script because there is a
204 sane default for the Karatsuba number.
210 It is well-tested, fuzzed, and fully standards-compliant (though not certified)
211 with POSIX `bc`. The math has been tested with 40+ million random problems, so
212 it is as correct as I can make it.
214 This `bc` can be used as a drop-in replacement for any existing `bc`. This `bc`
215 is also compatible with MinGW toolchains, though history is not supported on
218 In addition, this `bc` is considered complete; i.e., there will be no more
219 releases with additional features. However, it *is* actively maintained, so if
220 any bugs are found, they will be fixed in new releases. Also, additional
221 translations will also be added as they are provided.
223 ## Comparison to GNU `bc`
225 This `bc` compares favorably to GNU `bc`.
227 * It has more extensions, which make this `bc` more useful for scripting.
228 * This `bc` is a bit more POSIX compliant.
229 * It has a much less buggy parser. The GNU `bc` will give parse errors for what
230 is actually valid `bc` code, or should be. For example, putting an `else` on
231 a new line after a brace can cause GNU `bc` to give a parse error.
232 * This `bc` has fewer crashes.
233 * GNU `bc` calculates the wrong number of significant digits for `length(x)`.
234 * GNU `bc` will sometimes print numbers incorrectly. For example, when running
235 it on the file `tests/bc/power.txt` in this repo, GNU `bc` gets all the right
236 answers, but it fails to wrap the numbers at the proper place when outputting
238 * This `bc` is faster. (See [Performance](#performance).)
242 Because this `bc` packs more than `1` decimal digit per hardware integer, this
243 `bc` is faster than GNU `bc` and can be *much* faster. Full benchmarks can be
244 found at [manuals/benchmarks.md][19].
246 There is one instance where this `bc` is slower: if scripts are light on math.
247 This is because this `bc`'s intepreter is slightly slower than GNU `bc`, but
248 that is because it is more robust. See the [benchmarks][19].
252 To see what algorithms this `bc` uses, see the [algorithms manual][7].
256 Currently, this `bc` only has support for English (and US English), French,
257 German, Portuguese, Dutch, Polish, Russian, Japanese, and Chinese locales.
258 Patches are welcome for translations; use the existing `*.msg` files in
259 `locales/` as a starting point.
261 In addition, patches for improvements are welcome; the last two messages in
262 Portuguese were made with Google Translate, and the Dutch, Polish, Russian,
263 Japanese, and Chinese locales were all generated with [DeepL][22].
265 The message files provided assume that locales apply to all regions where a
266 language is used, but this might not be true for, e.g., `fr_CA` and `fr_CH`.
267 Any corrections or a confirmation that the current texts are acceptable for
268 those regions would be appreciated, too.
272 Other projects based on this bc are:
274 * [busybox `bc`][8]. The busybox maintainers have made their own changes, so any
275 bugs in the busybox `bc` should be reported to them.
277 * [toybox `bc`][9]. The maintainer has also made his own changes, so bugs in the
278 toybox `bc` should be reported there.
280 * [FreeBSD `bc`][23]. While the `bc` in FreeBSD is kept up-to-date, it is better
281 to [report bugs there][24], as well as [submit patches][25], and the
282 maintainers of the package will contact me if necessary.
286 This `bc` is written in pure ISO C99, using POSIX 2008 APIs.
290 This `bc` uses the commit message guidelines laid out in [this blog post][10].
292 ## Semantic Versioning
294 This `bc` uses [semantic versioning][11].
298 Items labeled with `(maintainer use only)` are not included in release source
303 .gitignore The git ignore file (maintainer use only).
304 configure A symlink to configure.sh to make packaging easier.
305 configure.sh The configure script.
306 functions.sh A script with functions used by other scripts.
307 install.sh Install script.
308 karatsuba.py Script to find the optimal Karatsuba number.
309 LICENSE.md A Markdown form of the BSD 2-clause License.
310 link.sh A script to link dc to bc.
311 locale_install.sh A script to install locales, if desired.
312 locale_uninstall.sh A script to uninstall locales.
313 Makefile.in The Makefile template.
314 manpage.sh Script to generate man pages from markdown files.
315 NOTICE.md List of contributors and copyright owners.
316 RELEASE.md A checklist for making a release (maintainer use only).
317 release.sh A script to test for release (maintainer use only).
318 safe-install.sh Safe install script from musl libc.
322 gen The bc math library, help texts, and code to generate C source.
323 include All header files.
324 locales Locale files, in .msg format. Patches welcome for translations.
325 manuals Manuals for both programs.
329 [1]: https://www.gnu.org/software/bc/
331 [5]: ./manuals/build.md
332 [6]: https://pkg.musl.cc/bc/
333 [7]: ./manuals/algorithms.md
334 [8]: https://git.busybox.net/busybox/tree/miscutils/bc.c
335 [9]: https://github.com/landley/toybox/blob/master/toys/pending/bc.c
336 [10]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
337 [11]: http://semver.org/
338 [12]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html
339 [17]: https://img.shields.io/coverity/scan/16609.svg
340 [18]: https://scan.coverity.com/projects/gavinhoward-bc
341 [19]: ./manuals/benchmarks.md
342 [20]: https://git.yzena.com/gavin/bc
343 [21]: https://gavinhoward.com/2020/04/i-am-moving-away-from-github/
344 [22]: https://www.deepl.com/translator
345 [23]: https://cgit.freebsd.org/src/tree/contrib/bc
346 [24]: https://bugs.freebsd.org/
347 [25]: https://reviews.freebsd.org/
348 [26]: ./manuals/bcl.3.md