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 `bc` only (no `dc`), use any one of the following commands for the
292 ./configure.sh --bc-only
294 ./configure.sh --disable-dc
297 Those commands are all equivalent.
299 ***Warning***: It is an error to use those options if `bc` has also been
300 disabled (see below).
304 To build `dc` only (no `bc`), use either one of the following commands for the
309 ./configure.sh --dc-only
311 ./configure.sh --disable-bc
314 Those commands are all equivalent.
316 ***Warning***: It is an error to use those options if `dc` has also been
317 disabled (see above).
319 <a name="build-history"/>
323 To disable signal handling, pass either the `-H` flag or the `--disable-history`
324 option to `configure.sh`, as follows:
328 ./configure.sh --disable-history
331 Both commands are equivalent.
333 History is automatically disabled when building for Windows or on another
334 platform that does not support the terminal handling that is required.
336 ***WARNING***: Of all of the code in the `bc`, this is the only code that is not
337 completely portable. If the `bc` does not work on your platform, your first step
338 should be to retry with history disabled.
340 ### NLS (Locale Support)
342 To disable locale support (use only English), pass either the `-N` flag or the
343 `--disable-nls` option to `configure.sh`, as follows:
347 ./configure.sh --disable-nls
350 Both commands are equivalent.
352 NLS (locale support) is automatically disabled when building for Windows or on
353 another platform that does not support the POSIX locale API or utilities.
357 By default, `bc` and `dc` print a prompt when in interactive mode. They both
358 have the command-line option `-P`/`--no-prompt`, which turns that off, but it
359 can be disabled permanently in the build by passing the `-P` flag or the
360 `--disable-prompt` option to `configure.sh`, as follows:
364 ./configure.sh --disable-prompt
367 Both commands are equivalent.
371 By default, `bc` and `dc` do not install all locales, but only the enabled
372 locales. If `DESTDIR` exists and is not empty, then they will install all of
373 the locales that exist on the system. The `-l` flag or `--install-all-locales`
374 option skips all of that and just installs all of the locales that `bc` and `dc`
375 have, regardless. To enable that behavior, you can pass the `-l` flag or the
376 `--install-all-locales` option to `configure.sh`, as follows:
380 ./configure.sh --install-all-locales
383 Both commands are equivalent.
387 This `bc` has 7 extra operators:
389 * `$` (truncation to integer)
390 * `@` (set precision)
391 * `@=` (set precision and assign)
392 * `<<` (shift number left, shifts radix right)
393 * `<<=` (shift number left and assign)
394 * `>>` (shift number right, shifts radix left)
395 * `>>=` (shift number right and assign)
397 There is no assignment version of `$` because it is a unary operator.
399 The assignment versions of the above operators are not available in `dc`, but
400 the others are, as the operators `$`, `@`, `H`, and `h`, respectively.
402 In addition, this `bc` has the option of outputting in scientific notation or
403 engineering notation. It can also take input in scientific or engineering
404 notation. On top of that, it has a pseudo-random number generator. (See the
405 full manual for more details.)
407 Extra operators, scientific notation, engineering notation, and the
408 pseudo-random number generator can be disabled by passing either the `-E` flag
409 or the `--disable-extra-math` option to `configure.sh`, as follows:
413 ./configure.sh --disable-extra-math
416 Both commands are equivalent.
418 This `bc` also has a larger library that is only enabled if extra operators and
419 the pseudo-random number generator are. More information about the functions can
420 be found in the Extended Library section of the full manual.
424 To disable installing manpages, pass either the `-M` flag or the
425 `--disable-man-pages` option to `configure.sh` as follows:
429 ./configure.sh --disable-man-pages
432 Both commands are equivalent.
436 The Karatsuba length is the point at which `bc` and `dc` switch from Karatsuba
437 multiplication to brute force, `O(n^2)` multiplication. It can be set by passing
438 the `-k` flag or the `--karatsuba-len` option to `configure.sh` as follows:
442 ./configure.sh --karatsuba-len 64
445 Both commands are equivalent.
449 ***WARNING***: The Karatsuba Length must be a **integer** greater than or equal
450 to `16` (to prevent stack overflow). If it is not, `configure.sh` will give an
455 The relevant `autotools`-style install options are supported in `configure.sh`:
468 ./configure.sh --prefix=/usr --localedir /usr/share/nls
473 They correspond to the environment variables `$PREFIX`, `$BINDIR`,
474 `$DATAROOTDIR`, `$DATADIR`, `$MANDIR`, `$MAN1DIR`, and `$LOCALEDIR`,
477 ***WARNING***: If the option is given, the value of the corresponding
478 environment variable is overridden.
480 ***WARNING***: If any long command-line options are used, the long form of all
481 other command-line options must be used. Mixing long and short options is not
486 The `configure.sh` script will accept an optimization level to pass to the
487 compiler. Because `bc` is orders of magnitude faster with optimization, I
488 ***highly*** recommend package and distro maintainers pass the highest
489 optimization level available in `CC` to `configure.sh` with the `-O` flag or
490 `--opt` option, as follows:
494 ./configure.sh --opt 3
497 Both commands are equivalent.
499 The build and install can then be run as normal:
506 As usual, `configure.sh` will also accept additional `CFLAGS` on the command
507 line, so for SSE4 architectures, the following can add a bit more speed:
510 CFLAGS="-march=native -msse4" ./configure.sh -O3
515 Building with link-time optimization (`-flto` in clang) can further increase the
516 performance. I ***highly*** recommend doing so.
518 I do **NOT*** recommend building with `-march=native`; doing so reduces this
521 Manual stripping is not necessary; non-debug builds are automatically stripped
526 Debug builds (which also disable optimization if no optimization level is given
527 and if no extra `CFLAGS` are given) can be enabled with either the `-g` flag or
528 the `--debug` option, as follows:
532 ./configure.sh --debug
535 Both commands are equivalent.
537 The build and install can then be run as normal:
544 ## Stripping Binaries
546 By default, when `bc` and `dc` are not built in debug mode, the binaries are
547 stripped. Stripping can be disabled with either the `-T` or the
548 `--disable-strip` option, as follows:
552 ./configure.sh --disable-strip
555 Both commands are equivalent.
557 The build and install can then be run as normal:
566 When built with both calculators, all available features, and `-Os` using
567 `clang` and `musl`, the executable is 140.4 kb (140,386 bytes) on `x86_64`. That
568 isn't much for what is contained in the binary, but if necessary, it can be
571 The single largest user of space is the `bc` calculator. If just `dc` is needed,
572 the size can be reduced to 107.6 kb (107,584 bytes).
574 The next largest user of space is history support. If that is not needed, size
575 can be reduced (for a build with both calculators) to 119.9 kb (119,866 bytes).
577 There are several reasons that history is a bigger user of space than `dc`
580 * `dc`'s lexer and parser are *tiny* compared to `bc`'s because `dc` code is
581 almost already in the form that it is executed in, while `bc` has to not only
582 adjust the form to be executable, it has to parse functions, loops, `if`
583 statements, and other extra features.
584 * `dc` does not have much extra code in the interpreter.
585 * History has a lot of const data for supporting `UTF-8` terminals.
586 * History pulls in a bunch of more code from the `libc`.
588 The next biggest user is extra math support. Without it, the size is reduced to
589 124.0 kb (123,986 bytes) with history and 107.6 kb (107,560 bytes) without
592 The reasons why extra math support is bigger than `dc`, besides the fact that
593 `dc` is small already, are:
595 * Extra math supports adds an extra math library that takes several kilobytes of
597 * Extra math support includes support for a pseudo-random number generator,
598 including the code to convert a series of pseudo-random numbers into a number
600 * Extra math support adds several operators.
602 The next biggest user is `dc`, so if just `bc` is needed, the size can be
603 reduced to 128.1 kb (128,096 bytes) with history and extra math support, 107.6
604 kb (107,576 bytes) without history and with extra math support, and 95.3 kb
605 (95,272 bytes) without history and without extra math support.
607 *Note*: all of these binary sizes were compiled using `musl` `1.2.0` as the
608 `libc`, making a fully static executable, with `clang` `9.0.1` (well,
609 `musl-clang` using `clang` `9.0.1`) as the compiler and using `-Os`
610 optimizations. These builds were done on an `x86_64` machine running Gentoo
615 The default test suite can be run with the following command:
621 To test `bc` only, run the following command:
627 To test `dc` only, run the following command:
633 This `bc`, if built, assumes a working, GNU-compatible `bc`, installed on the
634 system and in the `PATH`, to generate some tests, unless the `-G` flag or
635 `--disable-generated-tests` option is given to `configure.sh`, as follows:
639 ./configure.sh --disable-generated-tests
642 After running `configure.sh`, build and run tests as follows:
649 This `dc` also assumes a working, GNU-compatible `dc`, installed on the system
650 and in the `PATH`, to generate some tests, unless one of the above options is
651 given to `configure.sh`.
653 To generate test coverage, pass the `-c` flag or the `--coverage` option to
654 `configure.sh` as follows:
658 ./configure.sh --coverage
661 Both commands are equivalent.
663 ***WARNING***: Both `bc` and `dc` must be built for test coverage. Otherwise,
664 `configure.sh` will give an error.
666 [1]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html
667 [2]: https://www.gnu.org/software/bc/
668 [3]: https://www.musl-libc.org/
669 [4]: #build-environment-variables
671 [6]: #cross-compiling