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.
49 This `bc` should build unmodified on any POSIX-compliant system.
51 For more complex build requirements than the ones below, see the
56 For the default build with optimization, use the following commands in the root
66 To only build `bc`, use the following commands:
69 ./configure.sh --disable-dc
73 To only build `dc`, use the following commands:
76 ./configure.sh --disable-bc
82 For debug builds, use the following commands in the root directory:
91 To install, use the following command:
97 By default, `bc` and `dc` will be installed in `/usr/local`. For installing in
98 other locations, use the `PREFIX` environment variable when running
99 `configure.sh` or pass the `--prefix=<prefix>` option to `configure.sh`. See the
100 [build manual][5], or run `./configure.sh --help`, for more details.
104 This `bc` does provide a way to build a math library with C bindings. This is
105 done by the `-a` or `--library` options to `configure.sh`:
111 When building the library, the executables are not built. For more information,
112 see the [build manual][5].
114 The library API can be found in [`manuals/bcl.3.md`][26] or `man bcl` once the
115 library is installed.
117 The library is built as `bin/libbcl.a`.
119 ### Package and Distro Maintainers
121 #### Recommended Compiler
123 When I ran benchmarks with my `bc` compiled under `clang`, it performed much
124 better than when compiled under `gcc`. I recommend compiling this `bc` with
127 I also recommend building this `bc` with C11 if you can because `bc` will detect
128 a C11 compiler and add `_Noreturn` to any relevant function(s).
130 #### Recommended Optimizations
132 I wrote this `bc` with Separation of Concerns, which means that there are many
133 small functions that could be inlined. However, they are often called across
134 file boundaries, and the default optimizer can only look at the current file,
135 which means that they are not inlined.
137 Thus, because of the way this `bc` is built, it will automatically be slower
138 than other `bc` implementations when running scripts with no math. (My `bc`'s
139 math is *much* faster, so any non-trivial script should run faster in my `bc`.)
141 Some, or all, of the difference can be made up with the right optimizations. The
142 optimizations I recommend are:
145 2. `-flto` (link-time optimization)
149 Link-time optimization, in particular, speeds up the `bc` a lot. This is because
150 when link-time optimization is turned on, the optimizer can look across files
151 and inline *much* more heavily.
153 However, I recommend ***NOT*** using `-march=native`. Doing so will reduce this
154 `bc`'s performance, at least when building with link-time optimization. See the
155 [benchmarks][19] for more details.
157 #### Stripping Binaries
159 By default, non-debug binaries are stripped, but stripping can be disabled with
160 the `-T` option to `configure.sh`.
162 #### Using This `bc` as an Alternative
164 If this `bc` is packaged as an alternative to an already existing `bc` package,
165 it is possible to rename it in the build to prevent name collision. To prepend
166 to the name, just run the following:
169 EXECPREFIX=<some_prefix> ./configure.sh
172 To append to the name, just run the following:
175 EXECSUFFIX=<some_suffix> ./configure.sh
178 If a package maintainer wishes to add both a prefix and a suffix, that is
181 **Note**: The suggested name (and package name) when `bc` is not available is
184 #### Karatsuba Number
186 Package and distro maintainers have one tool at their disposal to build this
187 `bc` in the optimal configuration: `karatsuba.py`.
189 This script is not a compile-time or runtime prerequisite; it is for package and
190 distro maintainers to run once when a package is being created. It finds the
191 optimal Karatsuba number (see the [algorithms manual][7] for more information)
192 for the machine that it is running on.
194 The easiest way to run this script is with `make karatsuba`.
196 If desired, maintainers can also skip running this script because there is a
197 sane default for the Karatsuba number.
203 It is well-tested, fuzzed, and fully standards-compliant (though not certified)
204 with POSIX `bc`. The math has been tested with 40+ million random problems, so
205 it is as correct as I can make it.
207 This `bc` can be used as a drop-in replacement for any existing `bc`. This `bc`
208 is also compatible with MinGW toolchains, though history is not supported on
211 In addition, this `bc` is considered complete; i.e., there will be no more
212 releases with additional features. However, it *is* actively maintained, so if
213 any bugs are found, they will be fixed in new releases. Also, additional
214 translations will also be added as they are provided.
216 ## Comparison to GNU `bc`
218 This `bc` compares favorably to GNU `bc`.
220 * It has more extensions, which make this `bc` more useful for scripting.
221 * This `bc` is a bit more POSIX compliant.
222 * It has a much less buggy parser. The GNU `bc` will give parse errors for what
223 is actually valid `bc` code, or should be. For example, putting an `else` on
224 a new line after a brace can cause GNU `bc` to give a parse error.
225 * This `bc` has fewer crashes.
226 * GNU `bc` calculates the wrong number of significant digits for `length(x)`.
227 * GNU `bc` will sometimes print numbers incorrectly. For example, when running
228 it on the file `tests/bc/power.txt` in this repo, GNU `bc` gets all the right
229 answers, but it fails to wrap the numbers at the proper place when outputting
231 * This `bc` is faster. (See [Performance](#performance).)
235 Because this `bc` packs more than `1` decimal digit per hardware integer, this
236 `bc` is faster than GNU `bc` and can be *much* faster. Full benchmarks can be
237 found at [manuals/benchmarks.md][19].
239 There is one instance where this `bc` is slower: if scripts are light on math.
240 This is because this `bc`'s intepreter is slightly slower than GNU `bc`, but
241 that is because it is more robust. See the [benchmarks][19].
245 To see what algorithms this `bc` uses, see the [algorithms manual][7].
249 Currently, this `bc` only has support for English (and US English), French,
250 German, Portuguese, Dutch, Polish, Russian, Japanese, and Chinese locales.
251 Patches are welcome for translations; use the existing `*.msg` files in
252 `locales/` as a starting point.
254 In addition, patches for improvements are welcome; the last two messages in
255 Portuguese were made with Google Translate, and the Dutch, Polish, Russian,
256 Japanese, and Chinese locales were all generated with [DeepL][22].
258 The message files provided assume that locales apply to all regions where a
259 language is used, but this might not be true for, e.g., `fr_CA` and `fr_CH`.
260 Any corrections or a confirmation that the current texts are acceptable for
261 those regions would be appreciated, too.
265 Other projects based on this bc are:
267 * [busybox `bc`][8]. The busybox maintainers have made their own changes, so any
268 bugs in the busybox `bc` should be reported to them.
270 * [toybox `bc`][9]. The maintainer has also made his own changes, so bugs in the
271 toybox `bc` should be reported there.
273 * [FreeBSD `bc`][23]. While the `bc` in FreeBSD is kept up-to-date, it is better
274 to [report bugs there][24], as well as [submit patches][25], and the
275 maintainers of the package will contact me if necessary.
279 This `bc` is written in pure ISO C99, using POSIX 2008 APIs.
283 This `bc` uses the commit message guidelines laid out in [this blog post][10].
285 ## Semantic Versioning
287 This `bc` uses [semantic versioning][11].
291 Items labeled with `(maintainer use only)` are not included in release source
296 .gitignore The git ignore file (maintainer use only).
297 configure A symlink to configure.sh to make packaging easier.
298 configure.sh The configure script.
299 functions.sh A script with functions used by other scripts.
300 install.sh Install script.
301 karatsuba.py Script to find the optimal Karatsuba number.
302 LICENSE.md A Markdown form of the BSD 2-clause License.
303 link.sh A script to link dc to bc.
304 locale_install.sh A script to install locales, if desired.
305 locale_uninstall.sh A script to uninstall locales.
306 Makefile.in The Makefile template.
307 manpage.sh Script to generate man pages from markdown files.
308 NOTICE.md List of contributors and copyright owners.
309 RELEASE.md A checklist for making a release (maintainer use only).
310 release.sh A script to test for release (maintainer use only).
311 safe-install.sh Safe install script from musl libc.
315 gen The bc math library, help texts, and code to generate C source.
316 include All header files.
317 locales Locale files, in .msg format. Patches welcome for translations.
318 manuals Manuals for both programs.
322 [1]: https://www.gnu.org/software/bc/
324 [5]: ./manuals/build.md
325 [7]: ./manuals/algorithms.md
326 [8]: https://git.busybox.net/busybox/tree/miscutils/bc.c
327 [9]: https://github.com/landley/toybox/blob/master/toys/pending/bc.c
328 [10]: http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
329 [11]: http://semver.org/
330 [12]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html
331 [17]: https://img.shields.io/coverity/scan/16609.svg
332 [18]: https://scan.coverity.com/projects/gavinhoward-bc
333 [19]: ./manuals/benchmarks.md
334 [20]: https://git.yzena.com/gavin/bc
335 [21]: https://gavinhoward.com/2020/04/i-am-moving-away-from-github/
336 [22]: https://www.deepl.com/translator
337 [23]: https://cgit.freebsd.org/src/tree/contrib/bc
338 [24]: https://bugs.freebsd.org/
339 [25]: https://reviews.freebsd.org/
340 [26]: ./manuals/bcl.3.md