3 This `bc` attempts to be as portable as possible. It can be built on any
4 POSIX-compliant system.
6 To accomplish that, a POSIX-compatible, custom `configure.sh` script is used to
7 select build options, compiler, and compiler flags and generate a `Makefile`.
9 The general form of configuring, building, and installing this `bc` is as
13 [ENVIRONMENT_VARIABLE=<value>...] ./configure.sh [build_options...]
18 To get all of the options, including any useful environment variables, use
19 either one of the following commands:
26 ***WARNING***: even though `configure.sh` supports both option types, short and
27 long, it does not support handling both at the same time. Use only one type.
29 To learn the available `make` targets run the following command after running
30 the `configure.sh` script:
36 See [Build Environment Variables][4] for a more detailed description of all
37 accepted environment variables and [Build Options][5] for more detail about all
38 accepted build options.
40 <a name="cross-compiling"/>
44 To cross-compile this `bc`, an appropriate compiler must be present and assigned
45 to the environment variable `HOSTCC` or `HOST_CC` (the two are equivalent,
46 though `HOSTCC` is prioritized). This is in order to bootstrap core file(s), if
47 the architectures are not compatible (i.e., unlike i686 on x86_64). Thus, the
51 HOSTCC="/path/to/native/compiler" ./configure.sh
56 `HOST_CC` will work in exactly the same way.
58 `HOSTCFLAGS` and `HOST_CFLAGS` can be used to set compiler flags for `HOSTCC`.
59 (The two are equivalent, as `HOSTCC` and `HOST_CC` are.) `HOSTCFLAGS` is
60 prioritized over `HOST_CFLAGS`. If neither are present, `HOSTCC` (or `HOST_CC`)
61 uses `CFLAGS` (see [Build Environment Variables][4] for more details).
63 It is expected that `CC` produces code for the target system and `HOSTCC`
64 produces code for the host system. See [Build Environment Variables][4] for more
67 If an emulator is necessary to run the bootstrap binaries, it can be set with
68 the environment variable `GEN_EMU`.
70 <a name="build-environment-variables"/>
72 ## Build Environment Variables
74 This `bc` supports `CC`, `HOSTCC`, `HOST_CC`, `CFLAGS`, `HOSTCFLAGS`,
75 `HOST_CFLAGS`, `CPPFLAGS`, `LDFLAGS`, `LDLIBS`, `PREFIX`, `DESTDIR`, `BINDIR`,
76 `DATAROOTDIR`, `DATADIR`, `MANDIR`, `MAN1DIR`, `LOCALEDIR` `EXECSUFFIX`,
77 `EXECPREFIX`, `LONG_BIT`, `GEN_HOST`, and `GEN_EMU` environment variables in
78 `configure.sh`. Any values of those variables given to `configure.sh` will be
79 put into the generated Makefile.
81 More detail on what those environment variables do can be found in the following
86 C compiler for the target system. `CC` must be compatible with POSIX `c99`
87 behavior and options. However, **I encourage users to use any C99 or C11
88 compatible compiler they wish.**
90 If there is a space in the basename of the compiler, the items after the first
91 space are assumed to be compiler flags, and in that case, the flags are
92 automatically moved into CFLAGS.
96 ### `HOSTCC` or `HOST_CC`
98 C compiler for the host system, used only in [cross compiling][6]. Must be
99 compatible with POSIX `c99` behavior and options.
101 If there is a space in the basename of the compiler, the items after the first
102 space are assumed to be compiler flags, and in that case, the flags are
103 automatically moved into HOSTCFLAGS.
109 Command-line flags that will be passed verbatim to `CC`.
113 ### `HOSTCFLAGS` or `HOST_CFLAGS`
115 Command-line flags that will be passed verbatim to `HOSTCC` or `HOST_CC`.
117 Defaults to `$CFLAGS`.
121 Command-line flags for the C preprocessor. These are also passed verbatim to
122 both compilers (`CC` and `HOSTCC`); they are supported just for legacy reasons.
128 Command-line flags for the linker. These are also passed verbatim to both
129 compilers (`CC` and `HOSTCC`); they are supported just for legacy reasons.
135 Libraries to link to. These are also passed verbatim to both compilers (`CC` and
136 `HOSTCC`); they are supported just for legacy reasons and for cross compiling
137 with different C standard libraries (like [musl][3]).
143 The prefix to install to.
145 Can be overridden by passing the `--prefix` option to `configure.sh`.
147 Defaults to `/usr/local`.
151 Path to prepend onto `PREFIX`. This is mostly for distro and package
154 This can be passed either to `configure.sh` or `make install`. If it is passed
155 to both, the one given to `configure.sh` takes precedence.
161 The directory to install binaries in.
163 Can be overridden by passing the `--bindir` option to `configure.sh`.
165 Defaults to `$PREFIX/bin`.
169 The root directory to install data files in.
171 Can be overridden by passing the `--datarootdir` option to `configure.sh`.
173 Defaults to `$PREFIX/share`.
177 The directory to install data files in.
179 Can be overridden by passing the `--datadir` option to `configure.sh`.
181 Defaults to `$DATAROOTDIR`.
185 The directory to install manpages in.
187 Can be overridden by passing the `--mandir` option to `configure.sh`.
189 Defaults to `$DATADIR/man`
193 The directory to install Section 1 manpages in. Because both `bc` and `dc` are
194 Section 1 commands, this is the only relevant section directory.
196 Can be overridden by passing the `--man1dir` option to `configure.sh`.
198 Defaults to `$MANDIR/man1`.
202 The directory to install locales in.
204 Can be overridden by passing the `--localedir` option to `configure.sh`.
206 Defaults to `$DATAROOTDIR/locale`.
210 The suffix to append onto the executable names *when installing*. This is for
211 packagers and distro maintainers who want this `bc` as an option, but do not
212 want to replace the default `bc`.
218 The prefix to append onto the executable names *when building and installing*.
219 This is for packagers and distro maintainers who want this `bc` as an option,
220 but do not want to replace the default `bc`.
226 The number of bits in a C `long` type. This is mostly for the embedded space.
228 This `bc` uses `long`s internally for overflow checking. In C99, a `long` is
229 required to be 32 bits. For this reason, on 8-bit and 16-bit microcontrollers,
230 the generated code to do math with `long` types may be inefficient.
232 For most normal desktop systems, setting this is unnecessary, except that 32-bit
233 platforms with 64-bit longs may want to set it to `32`.
235 Defaults to the default value of `LONG_BIT` for the target platform. For
236 compliance with the `bc` spec, the minimum allowed value is `32`.
238 It is an error if the specified value is greater than the default value of
239 `LONG_BIT` for the target platform.
243 Whether to use `gen/strgen.c`, instead of `gen/strgen.sh`, to produce the C
244 files that contain the help texts as well as the math libraries. By default,
245 `gen/strgen.c` is used, compiled by `$HOSTCC` and run on the host machine. Using
246 `gen/strgen.sh` removes the need to compile and run an executable on the host
247 machine since `gen/strgen.sh` is a POSIX shell script. However, `gen/lib2.bc` is
248 perilously close to 4095 characters, the max supported length of a string
249 literal in C99 (and it could be added to in the future), and `gen/strgen.sh`
250 generates a string literal instead of an array, as `gen/strgen.c` does. For most
251 production-ready compilers, this limit probably is not enforced, but it could
252 be. Both options are still available for this reason.
254 If you are sure your compiler does not have the limit and do not want to compile
255 and run a binary on the host machine, set this variable to "0". Any other value,
256 or a non-existent value, will cause the build system to compile and run
263 The emulator to run bootstrap binaries under. This is only if the binaries
264 produced by `HOSTCC` (or `HOST_CC`) need to be run under an emulator to work.
268 <a name="build-options"/>
272 This `bc` comes with several build options, all of which are enabled by default.
274 All options can be used with each other, with a few exceptions that will be
277 **NOTE**: All long options with mandatory argumenst accept either one of the
287 To build the math library, use the following commands for the configure step:
291 ./configure.sh --library
294 Both commands are equivalent.
296 When the library is built, history, prompt, and locales are disabled, and the
297 functionality for `bc` and `dc` are both enabled, though the executables are
298 *not* built. This is because the library's options clash with the executables.
300 To build an optimized version of the library, users can pass optimization
301 options to `configure.sh` or include them in `CFLAGS`.
303 The library API can be found in `manuals/bcl.3.md` or `man bcl` once the library
306 The library is built as `bin/libbcl.a`.
310 To build `bc` only (no `dc`), use any one of the following commands for the
315 ./configure.sh --bc-only
317 ./configure.sh --disable-dc
320 Those commands are all equivalent.
322 ***Warning***: It is an error to use those options if `bc` has also been
323 disabled (see below).
327 To build `dc` only (no `bc`), use either one of the following commands for the
332 ./configure.sh --dc-only
334 ./configure.sh --disable-bc
337 Those commands are all equivalent.
339 ***Warning***: It is an error to use those options if `dc` has also been
340 disabled (see above).
342 <a name="build-history"/>
346 To disable signal handling, pass either the `-H` flag or the `--disable-history`
347 option to `configure.sh`, as follows:
351 ./configure.sh --disable-history
354 Both commands are equivalent.
356 History is automatically disabled when building for Windows or on another
357 platform that does not support the terminal handling that is required.
359 ***WARNING***: Of all of the code in the `bc`, this is the only code that is not
360 completely portable. If the `bc` does not work on your platform, your first step
361 should be to retry with history disabled.
363 ### NLS (Locale Support)
365 To disable locale support (use only English), pass either the `-N` flag or the
366 `--disable-nls` option to `configure.sh`, as follows:
370 ./configure.sh --disable-nls
373 Both commands are equivalent.
375 NLS (locale support) is automatically disabled when building for Windows or on
376 another platform that does not support the POSIX locale API or utilities.
380 By default, `bc` and `dc` print a prompt when in interactive mode. They both
381 have the command-line option `-P`/`--no-prompt`, which turns that off, but it
382 can be disabled permanently in the build by passing the `-P` flag or the
383 `--disable-prompt` option to `configure.sh`, as follows:
387 ./configure.sh --disable-prompt
390 Both commands are equivalent.
394 By default, `bc` and `dc` do not install all locales, but only the enabled
395 locales. If `DESTDIR` exists and is not empty, then they will install all of
396 the locales that exist on the system. The `-l` flag or `--install-all-locales`
397 option skips all of that and just installs all of the locales that `bc` and `dc`
398 have, regardless. To enable that behavior, you can pass the `-l` flag or the
399 `--install-all-locales` option to `configure.sh`, as follows:
403 ./configure.sh --install-all-locales
406 Both commands are equivalent.
410 This `bc` has 7 extra operators:
412 * `$` (truncation to integer)
413 * `@` (set precision)
414 * `@=` (set precision and assign)
415 * `<<` (shift number left, shifts radix right)
416 * `<<=` (shift number left and assign)
417 * `>>` (shift number right, shifts radix left)
418 * `>>=` (shift number right and assign)
420 There is no assignment version of `$` because it is a unary operator.
422 The assignment versions of the above operators are not available in `dc`, but
423 the others are, as the operators `$`, `@`, `H`, and `h`, respectively.
425 In addition, this `bc` has the option of outputting in scientific notation or
426 engineering notation. It can also take input in scientific or engineering
427 notation. On top of that, it has a pseudo-random number generator. (See the
428 full manual for more details.)
430 Extra operators, scientific notation, engineering notation, and the
431 pseudo-random number generator can be disabled by passing either the `-E` flag
432 or the `--disable-extra-math` option to `configure.sh`, as follows:
436 ./configure.sh --disable-extra-math
439 Both commands are equivalent.
441 This `bc` also has a larger library that is only enabled if extra operators and
442 the pseudo-random number generator are. More information about the functions can
443 be found in the Extended Library section of the full manual.
447 To disable installing manpages, pass either the `-M` flag or the
448 `--disable-man-pages` option to `configure.sh` as follows:
452 ./configure.sh --disable-man-pages
455 Both commands are equivalent.
459 The Karatsuba length is the point at which `bc` and `dc` switch from Karatsuba
460 multiplication to brute force, `O(n^2)` multiplication. It can be set by passing
461 the `-k` flag or the `--karatsuba-len` option to `configure.sh` as follows:
465 ./configure.sh --karatsuba-len 64
468 Both commands are equivalent.
472 ***WARNING***: The Karatsuba Length must be a **integer** greater than or equal
473 to `16` (to prevent stack overflow). If it is not, `configure.sh` will give an
478 The relevant `autotools`-style install options are supported in `configure.sh`:
491 ./configure.sh --prefix=/usr --localedir /usr/share/nls
496 They correspond to the environment variables `$PREFIX`, `$BINDIR`,
497 `$DATAROOTDIR`, `$DATADIR`, `$MANDIR`, `$MAN1DIR`, and `$LOCALEDIR`,
500 ***WARNING***: If the option is given, the value of the corresponding
501 environment variable is overridden.
503 ***WARNING***: If any long command-line options are used, the long form of all
504 other command-line options must be used. Mixing long and short options is not
509 The `configure.sh` script will accept an optimization level to pass to the
510 compiler. Because `bc` is orders of magnitude faster with optimization, I
511 ***highly*** recommend package and distro maintainers pass the highest
512 optimization level available in `CC` to `configure.sh` with the `-O` flag or
513 `--opt` option, as follows:
517 ./configure.sh --opt 3
520 Both commands are equivalent.
522 The build and install can then be run as normal:
529 As usual, `configure.sh` will also accept additional `CFLAGS` on the command
530 line, so for SSE4 architectures, the following can add a bit more speed:
533 CFLAGS="-march=native -msse4" ./configure.sh -O3
538 Building with link-time optimization (`-flto` in clang) can further increase the
539 performance. I ***highly*** recommend doing so.
541 I do **NOT*** recommend building with `-march=native`; doing so reduces this
544 Manual stripping is not necessary; non-debug builds are automatically stripped
549 Debug builds (which also disable optimization if no optimization level is given
550 and if no extra `CFLAGS` are given) can be enabled with either the `-g` flag or
551 the `--debug` option, as follows:
555 ./configure.sh --debug
558 Both commands are equivalent.
560 The build and install can then be run as normal:
567 ## Stripping Binaries
569 By default, when `bc` and `dc` are not built in debug mode, the binaries are
570 stripped. Stripping can be disabled with either the `-T` or the
571 `--disable-strip` option, as follows:
575 ./configure.sh --disable-strip
578 Both commands are equivalent.
580 The build and install can then be run as normal:
589 When built with both calculators, all available features, and `-Os` using
590 `clang` and `musl`, the executable is 140.4 kb (140,386 bytes) on `x86_64`. That
591 isn't much for what is contained in the binary, but if necessary, it can be
594 The single largest user of space is the `bc` calculator. If just `dc` is needed,
595 the size can be reduced to 107.6 kb (107,584 bytes).
597 The next largest user of space is history support. If that is not needed, size
598 can be reduced (for a build with both calculators) to 119.9 kb (119,866 bytes).
600 There are several reasons that history is a bigger user of space than `dc`
603 * `dc`'s lexer and parser are *tiny* compared to `bc`'s because `dc` code is
604 almost already in the form that it is executed in, while `bc` has to not only
605 adjust the form to be executable, it has to parse functions, loops, `if`
606 statements, and other extra features.
607 * `dc` does not have much extra code in the interpreter.
608 * History has a lot of const data for supporting `UTF-8` terminals.
609 * History pulls in a bunch of more code from the `libc`.
611 The next biggest user is extra math support. Without it, the size is reduced to
612 124.0 kb (123,986 bytes) with history and 107.6 kb (107,560 bytes) without
615 The reasons why extra math support is bigger than `dc`, besides the fact that
616 `dc` is small already, are:
618 * Extra math supports adds an extra math library that takes several kilobytes of
620 * Extra math support includes support for a pseudo-random number generator,
621 including the code to convert a series of pseudo-random numbers into a number
623 * Extra math support adds several operators.
625 The next biggest user is `dc`, so if just `bc` is needed, the size can be
626 reduced to 128.1 kb (128,096 bytes) with history and extra math support, 107.6
627 kb (107,576 bytes) without history and with extra math support, and 95.3 kb
628 (95,272 bytes) without history and without extra math support.
630 *Note*: all of these binary sizes were compiled using `musl` `1.2.0` as the
631 `libc`, making a fully static executable, with `clang` `9.0.1` (well,
632 `musl-clang` using `clang` `9.0.1`) as the compiler and using `-Os`
633 optimizations. These builds were done on an `x86_64` machine running Gentoo
638 The default test suite can be run with the following command:
644 To test `bc` only, run the following command:
650 To test `dc` only, run the following command:
656 This `bc`, if built, assumes a working, GNU-compatible `bc`, installed on the
657 system and in the `PATH`, to generate some tests, unless the `-G` flag or
658 `--disable-generated-tests` option is given to `configure.sh`, as follows:
662 ./configure.sh --disable-generated-tests
665 After running `configure.sh`, build and run tests as follows:
672 This `dc` also assumes a working, GNU-compatible `dc`, installed on the system
673 and in the `PATH`, to generate some tests, unless one of the above options is
674 given to `configure.sh`.
676 To generate test coverage, pass the `-c` flag or the `--coverage` option to
677 `configure.sh` as follows:
681 ./configure.sh --coverage
684 Both commands are equivalent.
686 ***WARNING***: Both `bc` and `dc` must be built for test coverage. Otherwise,
687 `configure.sh` will give an error.
689 [1]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html
690 [2]: https://www.gnu.org/software/bc/
691 [3]: https://www.musl-libc.org/
692 [4]: #build-environment-variables
694 [6]: #cross-compiling