bc
WARNING: New user registration for https://git.gavinhoward.com/ is disabled
because of spam. If you need to report a bug with bc
, email gavin at this site
minus the git.
part for an account, and I will create one for you. Or you can
report an issue at GitHub.
WARNING: This project has moved to https://git.gavinhoward.com/ for these reasons, though GitHub will remain a mirror.
This is an implementation of the POSIX bc
calculator that implements
GNU bc
extensions, as well as the period (.
) extension for the BSD
flavor of bc
.
For more information, see this bc
's full manual.
This bc
also includes an implementation of dc
in the same binary, accessible
via a symbolic link, which implements all FreeBSD and GNU extensions. (If a
standalone dc
binary is desired, bc
can be copied and renamed to dc
.) The
!
command is omitted; I believe this poses security concerns and that such
functionality is unnecessary.
For more information, see the dc
's full manual.
This bc
also provides bc
's math as a library with C bindings, called bcl
.
For more information, see the full manual for bcl
.
This bc
is Free and Open Source Software (FOSS). It is offered under the BSD
2-clause License. Full license text may be found in the LICENSE.md
file.
This bc
only requires either:
Since POSIX 2008 with XSI requires the existence of a C99 compiler as c99
, any
POSIX and XSI-compatible system will have everything needed.
POSIX-compatible systems that are known to work:
In addition, there is compatibility code to make this bc
work on Windows.
Please submit bug reports if this bc
does not build out of the box on any
system.
This bc
should build unmodified on any POSIX-compliant system or on Windows
starting with Windows 10 (though earlier versions may work).
For more complex build requirements than the ones below, see the build manual.
There is no guarantee that this bc
will work on any version of Windows earlier
than Windows 10 (I cannot test on earlier versions), but it is guaranteed to
work on Windows 10 at least.
Also, if building with MSBuild, the MSBuild bundled with Visual Studio is required.
Note: Unlike the POSIX-compatible platforms, only one build configuration is supported on Windows: extra math and history enabled, NLS (locale support) disabled, with both calculators built.
bc
To build bc
, you can open the vs/bc.sln
file in Visual Studio, select the
configuration, and build.
You can also build using MSBuild with the following from the root directory:
msbuild -property:Configuration=<config> vs/bc.sln
where <config>
is either one of Debug
or Release
.
On Windows, the calculators are built as vs/bin/<platform>/<config>/bc.exe
and
vs/bin/<Platform>/<Config>/dc.exe
, where <platform>
can be either Win32
or
x64
, and <config>
can be Debug
or Release
.
Note: On Windows, dc.exe
is just copied from bc.exe
; it is not linked.
Patches are welcome for a way to do that.
bcl
(Library)To build the library, you can open the vs/bcl.sln
file in Visual Studio,
select the configuration, and build.
You can also build using MSBuild with the following from the root directory:
msbuild -property:Configuration=<config> vs/bcl.sln
where <config>
is either one of Debug
, ReleaseMD
, or ReleaseMT
.
On Windows, the library is built as vs/lib/<platform>/<config>/bcl.lib
, where
<platform>
can be either Win32
or x64
, and <config>
can be Debug
,
ReleaseMD
, or ReleaseMT
.
On POSIX-compatible systems, bc
is built as bin/bc
and dc
is built as
bin/dc
by default.
For the default build with optimization, use the following commands in the root directory:
./configure.sh -O3
make
To only build bc
, use the following commands:
./configure.sh --disable-dc
make
To only build dc
, use the following commands:
./configure.sh --disable-bc
make
For debug builds, use the following commands in the root directory:
./configure.sh -g
make
To install, use the following command:
make install
By default, bc
and dc
will be installed in /usr/local
. For installing in
other locations, use the PREFIX
environment variable when running
configure.sh
or pass the --prefix=<prefix>
option to configure.sh
. See the
build manual, or run ./configure.sh --help
, for more details.
To build the math library, pass the -a
or --library
options to
configure.sh
:
./configure.sh -a
When building the library, the executables are not built. For more information, see the build manual.
The library API can be found in manuals/bcl.3.md
or man bcl
once the
library is installed.
This section is for package and distro maintainers.
Out-of-source builds are supported; just call configure.sh
from the directory
where the actual build will happen.
For example, if the source is in bc
, the build should happen in build
, then
call configure.sh
and make
like so:
../bc/configure.sh
make
WARNING: The path to configure.sh
from the build directory must not have
spaces because make
does not support target names with spaces.
When I ran benchmarks with my bc
compiled under clang
, it performed much
better than when compiled under gcc
. I recommend compiling this bc
with
clang
.
I also recommend building this bc
with C11 if you can because bc
will detect
a C11 compiler and add _Noreturn
to any relevant function(s).
I wrote this bc
with Separation of Concerns, which means that there are many
small functions that could be inlined. However, they are often called across
file boundaries, and the default optimizer can only look at the current file,
which means that they are not inlined.
Thus, because of the way this bc
is built, it will automatically be slower
than other bc
implementations when running scripts with no math. (My bc
's
math is much faster, so any non-trivial script should run faster in my bc
.)
Some, or all, of the difference can be made up with the right optimizations. The optimizations I recommend are:
-O3
-flto
(link-time optimization)in that order.
Link-time optimization, in particular, speeds up the bc
a lot. This is because
when link-time optimization is turned on, the optimizer can look across files
and inline much more heavily.
However, I recommend NOT using -march=native
. Doing so will reduce this
bc
's performance, at least when building with link-time optimization. See the
benchmarks for more details.
By default, non-debug binaries are stripped, but stripping can be disabled with
the -T
option to configure.sh
.
bc
as an AlternativeIf this bc
is packaged as an alternative to an already existing bc
package,
it is possible to rename it in the build to prevent name collision. To prepend
to the name, just run the following:
EXECPREFIX=<some_prefix> ./configure.sh
To append to the name, just run the following:
EXECSUFFIX=<some_suffix> ./configure.sh
If a package maintainer wishes to add both a prefix and a suffix, that is allowed.
Note: The suggested name (and package name) when bc
is not available is
bc-gh
.
Package and distro maintainers have one tool at their disposal to build this
bc
in the optimal configuration: scripts/karatsuba.py
.
This script is not a compile-time or runtime prerequisite; it is for package and distro maintainers to run once when a package is being created. It finds the optimal Karatsuba number (see the algorithms manual for more information) for the machine that it is running on.
The easiest way to run this script is with make karatsuba
.
If desired, maintainers can also skip running this script because there is a sane default for the Karatsuba number.
This bc
is robust.
It is well-tested, fuzzed, and fully standards-compliant (though not certified)
with POSIX bc
. The math has been tested with 40+ million random problems, so
it is as correct as I can make it.
This bc
can be used as a drop-in replacement for any existing bc
. This bc
is also compatible with MinGW toolchains.
In addition, this bc
is considered complete; i.e., there will be no more
releases with additional features. However, it is actively maintained, so if
any bugs are found, they will be fixed in new releases. Also, additional
translations will also be added as they are provided.
If I (Gavin D. Howard) get hit by a bus and future programmers need to handle work themselves, the best place to start is the Development manual.
I have developed (using other people's code to start) vim
syntax files
for this bc
and dc
, including the extensions.
bc
LibsI have gathered some excellent bc
and dc
libraries. These libraries
may prove useful to any serious users.
bc
This bc
compares favorably to GNU bc
.
bc
builds natively on Windows.bc
more useful for scripting. (See
Extensions.)bc
is a bit more POSIX compliant.bc
will give parse errors for what
is actually valid bc
code, or should be. For example, putting an else
on
a new line after a brace can cause GNU bc
to give a parse error.bc
has fewer crashes.bc
calculates the wrong number of significant digits for length(x)
.bc
will sometimes print numbers incorrectly. For example, when running
it on the file tests/bc/power.txt
in this repo, GNU bc
gets all the right
answers, but it fails to wrap the numbers at the proper place when outputting
to a file.bc
is faster. (See Performance.)Because this bc
packs more than 1
decimal digit per hardware integer, this
bc
is faster than GNU bc
and can be much faster. Full benchmarks can be
found at manuals/benchmarks.md.
There is one instance where this bc
is slower: if scripts are light on math.
This is because this bc
's intepreter is slightly slower than GNU bc
, but
that is because it is more robust. See the benchmarks.
Below is a non-comprehensive list of extensions that this bc
and dc
have
that all others do not.
!
operator has higher precedence than the !
operator in other bc
implementations.bc
uses it, and the BSD bc
does not. Mine does both.)scale
, ibase
, and obase
instead of needing to restore them in every function.abs
is a
keyword (a built-in function), but if some script actually defines a function
called that, it's possible to tell my bc
to not treat it as a keyword, which
will make the script parses correctly.-1
and less than 1
.length()
built-in function. (In dc
, the
Y
command will do this for arrays, and the Z
command will do this for both
numbers and strings.)abs()
built-in function. (This is the b
command in dc
.)is_number()
and is_string()
built-in functions. (These tell whether a
variable is holding a string or a number, for runtime type checking. The
commands are u
and t
in dc
.)bc
only, the divmod()
built-in function for computing a quotient and
remainder at the same time.bc
only, the asciify()
built-in function for converting an array to a
string.$
truncation operator. (It's the same in bc
and dc
.)@
"set scale" operator. (It's the same in bc
and dc
.)<<
and >>
in bc
, H
and h
in dc
.)scale
, ibase
, and
obase
.bc
. (This always existed in
dc
.)'
command in dc
for the depth of the execution stack.y
command in dc
for the depth of register stacks.stream
keyword to do the same thing as the P
command in dc
.POSIXLY_CORRECT
, BC_ENV_ARGS
, and
BC_LINE_LENGTH
.To see what algorithms this bc
uses, see the algorithms manual.
Currently, there is no locale support on Windows.
Additionally, this bc
only has support for English (and US English), French,
German, Portuguese, Dutch, Polish, Russian, Japanese, and Chinese locales.
Patches are welcome for translations; use the existing *.msg
files in
locales/
as a starting point.
In addition, patches for improvements are welcome; the last two messages in Portuguese were made with Google Translate, and the Dutch, Polish, Russian, Japanese, and Chinese locales were all generated with DeepL.
The message files provided assume that locales apply to all regions where a
language is used, but this might not be true for, e.g., fr_CA
and fr_CH
.
Any corrections or a confirmation that the current texts are acceptable for
those regions would be appreciated, too.
Other projects based on this bc are:
bc
. The busybox maintainers have made their own changes, so any
bugs in the busybox bc
should be reported to them.bc
. The maintainer has also made his own changes, so bugs in the
toybox bc
should be reported there.bc
. While the bc
in FreeBSD is kept up-to-date, it is better
to report bugs there, as well as submit patches, and the
maintainers of the package will contact me if necessary.bc
. Any bugs in that bc
should be reported to me, but do
expect bugs because the version is old.bc
. Any bugs in that bc
can be reported here.This is a non-comprehensive list of Linux distros that use this bc
as the
system bc
:
bc
, but not exclusive.Other Linux distros package it as a second-class alternative, usually as bc-gh
or howard-bc
.
This bc
is written in pure ISO C99, using POSIX 2008 APIs with custom Windows
compatibility code.
This bc
uses the commit message guidelines laid out in this blog post.
This bc
uses semantic versioning.
This repository is 100% AI-Free code.
Items labeled with (maintainer use only)
are not included in release source
tarballs.
Files:
.gitignore The git ignore file (maintainer use only).
.gitattributes The git attributes file (maintainer use only).
bcl.pc.in A template pkg-config file for bcl.
configure A symlink to configure.sh to make packaging easier.
configure.sh The configure script.
LICENSE.md A Markdown form of the BSD 2-clause License.
Makefile.in The Makefile template.
NEWS.md The changelog.
NOTICE.md List of contributors and copyright owners.
Folders:
benchmarks A folder of benchmarks for various aspects of bc performance.
gen The bc math library, help texts, and code to generate C source.
include All header files.
locales Locale files, in .msg format. Patches welcome for translations.
manuals Manuals for both programs.
src All source code.
scripts A bunch of shell scripts to help with development and building.
tests All tests.
vs Files needed for the build on Windows.