An implementation of Unix dc and POSIX bc with GNU and BSD extensions. Finished, but well-maintained.
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This is a production release that fixes a build problem in the FreeBSD base system.

All other users do NOT need to upgrade.


This is a production release that fixes prompt bugs with editline and readline where the BC_PROMPT environment variable was not being respected.

This also fixes editline and readline output on EOF.


This is a production release that fixes a build problem in the FreeBSD base system, as well as a problem in the en_US locale. If you don't have problems with either, you do not need to upgrade.


This is a production release that adds features and has a few bug fixes.

First, support for editline and readline history has been added. To use editline, pass -e to, and to use readline, pass -r.

Second, history support for Windows has been fixed and re-enabled.

Third, command-line options to set scale, ibase, obase, and seed were added. This was requested long ago, and I originally disagreed with the idea.

Fourth, the manuals had typos and were missing information. That has been fixed.

Fifth, the manuals received different formatting to be more readable as manpages.


This is a production release that fixes this bc's behavior on ^D to match GNU bc.


This is a production release that fixes two bugs in history:

  • Without prompt, the cursor could not be placed on the first character in a line.
  • Home and End key handling in tmux was fixed.

Any users that do not care about these improvements do not need to upgrade.


This is a production release that fixes one bug, a parse error when passing a file to bc using -f if that file had a multiline comment or string in it.


This is a production release that fixes one bug, a segmentation fault if argv[0] equals NULL.

This is not a critical bug; there will be no vulnerability as far as I can tell. There is no need to update if you do not wish to.


This is a production release that fixes two parse bugs when in POSIX standard mode. One of these bugs was due to a quirk of the POSIX grammar, and the other was because bc was too strict.


This is a production release that adds a new feature, fixes some bugs, and adds out-of-source builds and a pkg-config file for bcl.

The new feature is the ability to turn off exiting on expressions. It is also possible to set the default using This behavior used to exist with the BC_EXPR_EXIT environment variable, which is now used again.

Bugs fixed include:

  • Some possible race conditions with error handling.
  • Install and uninstall targets for bcl did not work.


This is a production release that completes a bug fix from 5.1.0. The bug exists in all versions of bc.

The bug was that if statements without else statements would not be handled correctly at the end of files or right before a function definition.


This is a production release with some fixes and new features.

  • Fixed a bug where an if statement without an else before defining a function caused an error.
  • Fixed a bug with the bc banner and -q.
  • Fixed a bug on Windows where files were not read correctly.
  • Added a command-line flag (-z) to make bc and dc print leading zeroes on numbers -1 < x < 1.
  • Added four functions to lib2.bc (plz(), plznl(), pnlz(), and pnlznl()) to allow printing numbers with or without leading zeros, despite the use of -z or not.
  • Added builtin functions to query global state like line length, global stacks, and leading zeroes.
  • Added a command-line flag (-L) to disable wrapping when printing numbers.
  • Improved builds on Windows.


This is a production release with one fix for a flaky test. If you have not experienced problems with the test suite, you do NOT need to upgrade.

The test was one that tested whether bc fails gracefully when it can't allocate memory. Unfortunately, there are cases when Linux and FreeBSD lie and pretend to allocate the memory.

The reason they do this is because a lot of programs don't use all of the memory they allocate, so those OS's usually get away with it.

However, this bc uses all of the memory it allocates (at least at page granularity), so when it tries to use the memory, FreeBSD and Linux kill it.

This only happens sometimes, however. Other times (on my machine), they do, in fact, refuse the request.

So I changed the test to not test for that because I think the graceful failure code won't really change much.


This is a production release with two fixes:

  • Fix for the build on Mac OSX.
  • Fix for the build on Android.

Users that do not use those platforms do NOT need to update.


This is a major production release with several changes:

  • Added support for OpenBSD's pledge() and unveil().
  • Fixed print bug where a backslash newline combo was printed even if only one digit was left, something I blindly copied from GNU bc, like a fool.
  • Fixed bugs in the manuals.
  • Fixed a possible multiplication overflow in power.
  • Temporary numbers are garbage collected if allocation fails, and the allocation is retried. This is to make bc and dc more resilient to running out of memory.
  • Limited the number of temporary numbers and made the space for them static so that allocating more space for them cannot fail.
  • Allowed integers with non-zero scale to be used with power, places, and shift operators.
  • Added greatest common divisor and least common multiple to lib2.bc.
  • Added SIGQUIT handling to history.
  • Added a command to dc (y) to get the length of register stacks.
  • Fixed multi-digit bugs in lib2.bc.
  • Removed the no prompt build option.
  • Created settings that builders can set defaults for and users can set their preferences for. This includes the bc banner, resetting on SIGINT, TTY mode, and prompt.
  • Added history support to Windows.
  • Fixed bugs with the handling of register names in dc.
  • Fixed bugs with multi-line comments and strings in both calculators.
  • Added a new error type and message for dc when register stacks don't have enough items.
  • Optimized string allocation.
  • Made bc and dc UTF-8 capable.
  • Fixed a bug with void functions.
  • Fixed a misspelled symbol in bcl. This is technically a breaking change, which requires this to be 5.0.0.
  • Added the ability for users to get the copyright banner back.
  • Added the ability for users to have bc and dc quit on SIGINT.
  • Added the ability for users to disable prompt and TTY mode by environment variables.
  • Added the ability for users to redefine keywords. This is another reason this is 5.0.0.
  • Added dc's modular exponentiation and divmod to bc.
  • Added the ability to assign strings to variables and array elements and pass them to functions in bc.
  • Added dc's asciify command and stream printing to bc.
  • Added a command to dc (Y) to get the length of an array.
  • Added a command to dc (,) to get the depth of the execution stack.
  • Added bitwise and, or, xor, left shift, right shift, reverse, left rotate, right rotate, and mod functions to lib2.bc.
  • Added the functions s2u(x) and s2un(x,n), to lib2.bc.


This is a production release that fixes two bugs:

  1. If no files are used and the first statement on stdin is invalid, scale would not be set to 20 even if -l was used.
  2. When using history, bc failed to respond properly to SIGSTOP and SIGTSTP.


This is a production release that only adds one thing: flushing output when it is printed with a print statement.


This is a production release with many fixes, a new command-line option, and a big surprise:

  • A bug was fixed in dc's P command where the item on the stack was not popped.
  • Various bugs in the manuals have been fixed.
  • A known bug was fixed where history did not interact well with prompts printed by user code without newlines.
  • A new command-line option, -R and --no-read-prompt was added to disable just the prompt when using read() (bc) or ? (dc).
  • And finally, official support for Windows was added.

The last item is why this is a major version bump.

Currently, only one set of build options (extra math and prompt enabled, history and NLS/locale support disabled, both calculators enabled) is supported on Windows. However, both debug and release builds are supported.

In addition, Windows builds are supported for the the library (bcl).

For more details about how to build on Windows, see the README or the build manual.


This is a production release that fixes a small bug.

The bug was that output was not flushed before a read() call, so prompts without a newline on the end were not flushed before the read() call.

This is such a tiny bug that users only need to upgrade if they are affected.


This is a production release with one tweak and fixes for manuals.

The tweak is that length(0) returns 1 instead of 0. In 3.3.1, I changed it so length(0.x), where x could be any number of digits, returned the scale, but length(0) still returned 0 because I believe that 0 has 0 significant digits.

After request of FreeBSD and considering the arguments of a mathematician, compatibility with other bc's, and the expectations of users, I decided to make the change.

The fixes for manuals fixed a bug where -- was rendered as -.


This is a production release that fixes a divide-by-zero bug in root() in the extended math library. All previous versions with root() have the bug.


This is a production release that fixes a bug.

The bug was in the reporting of number length when the value was 0.


This is a production release that changes one behavior and fixes documentation bugs.

The changed behavior is the treatment of -e and -f when given through BC_ENV_ARGS or DC_ENV_ARGS. Now bc and dc do not exit when those options (or their equivalents) are given through those environment variables. However, bc and dc still exit when they or their equivalents are given on the command-line.


This is a production release that removes a small non-portable shell operation in This problem was only noticed on OpenBSD, not FreeBSD or Linux.

Non-OpenBSD users do NOT need to upgrade, although NetBSD users may also need to upgrade.


This is a production release that fixes the build on FreeBSD.

There was a syntax error in that the Linux shell did not catch, and FreeBSD depends on the existence of tests/

All users that already upgraded to 3.2.5 should update to this release, with my apologies for the poor release of 3.2.5. Other users should skip 3.2.5 in favor of this version.


This is a production release that fixes several bugs and adds a couple small things.

The two most important bugs were bugs that causes dc to access memory out-of-bounds (crash in debug builds). This was found by upgrading to afl++ from afl. Both were caused by a failure to distinguish between the same two cases.

Another bug was the failure to put all of the licenses in the file.

Third, some warnings by scan-build were found and eliminated. This needed one big change: bc and dc now bail out as fast as possible on fatal errors instead of unwinding the stack.

Fourth, the pseudo-random number now attempts to seed itself with /dev/random if /dev/urandom fails.

Finally, this release has a few quality-of-life changes to the build system. The usage should not change at all; the only thing that changed was making sure the was written to rebuild properly when headers changed and to not rebuild when not necessary.


This is a production release that fixes a warning on gcc 6 or older, which does not have an attribute that is used.

Users do NOT need to upgrade if they don't use gcc 6 or older.


This is a production release that fixes a bug in gen/ I recently changed gen/strgen.c, but I did not change gen/

Users that do not use gen/ do not need to upgrade.


This is a production release that fixes a portability bug in The bug was using the GNU find extension -wholename.


This is a production release that has one fix for bcl(3). It is technically not a bug fix since the behavior is undefined, but the BclNumbers that bcl_divmod() returns will be set to BCL_ERROR_INVALID_NUM if there is an error. Previously, they were not set.


This is a production release that has one bug fix and a major addition.

The bug fix was a missing auto variable in the bessel j() function in the math library.

The major addition is a way to build a version of bc's math code as a library. This is done with the -a option to The API for the library can be read in ./manuals/ or man bcl once the library is installed with make install.

This library was requested by developers before I even finished version 1.0, but I could not figure out how to do it until now.

If the library has API breaking changes, the major version of bc will be incremented.


This is a production release that fixes a new warning from Clang 12 for FreeBSD and also removes some possible undefined behavior found by UBSan that compilers did not seem to take advantage of.

Users do NOT need to upgrade, if they do not want to.


This is a production release that fixes the Chinese locales (which caused bc to crash) and a crash caused by bc executing code when it should not have been able to.



This is a production release that fixes one bug, changes two behaviors, and removes one environment variable.

The bug is like the one in the last release except it applies if files are being executed. I also made the fix more general.

The behavior that was changed is that bc now exits when given -e, -f, --expression or --file. However, if the last one of those is -f- (using stdin as the file), bc does not exit. If -f- exists and is not the last of the -e and -f options (and equivalents), bc gives a fatal error and exits.

Next, I removed the BC_EXPR_EXIT and DC_EXPR_EXIT environment variables since their use is not needed with the behavior change.

Finally, I made it so bc does not print the header, though the -q and --quiet options were kept for compatibility with GNU bc.


This is a production release that fixes one minor bug: if bc was invoked like the following, it would error:

echo "if (1 < 3) 1" | bc

Unless users run into this bug, they do not need to upgrade, but it is suggested that they do.


This is a production release that adds a way to install all locales. Users do NOT need to upgrade.

For package maintainers wishing to make use of the change, just pass -l to


This is a production release that adds two Spanish locales. Users do NOT need to upgrade, unless they want those locales.


This is a production release that adjusts one behavior, fixes eight bugs, and improves manpages for FreeBSD. Because this release fixes bugs, users and package maintainers should update to this version as soon as possible.

The behavior that was adjusted was how code from the -e and -f arguments (and equivalents) were executed. They used to be executed as one big chunk, but in this release, they are now executed line-by-line.

The first bug fix in how output to stdout was handled in SIGINT. If a SIGINT came in, the stdout buffer was not correctly flushed. In fact, a clean-up function was not getting called. This release fixes that bug.

The second bug is in how dc handled input from stdin. This affected bc as well since it was a mishandling of the stdin buffer.

The third fixed bug was that bc and dc could abort() (in debug mode) when receiving a SIGTERM. This one was a race condition with pushing and popping items onto and out of vectors.

The fourth bug fixed was that bc could leave extra items on the stack and thus, not properly clean up some memory. (The memory would still get free()'ed, but it would not be free()'ed when it could have been.)

The next two bugs were bugs in bc's parser that caused crashes when executing the resulting code.

The last two bugs were crashes in dc that resulted from mishandling of strings.

The manpage improvement was done by switching from ronn to Pandoc to generate manpages. Pandoc generates much cleaner manpages and doesn't leave blank lines where they shouldn't be.


This is a production release that adds one new feature: specific manpages.

Before this release, bc and dc only used one manpage each that referred to various build options. This release changes it so there is one manpage set per relevant build type. Each manual only has information about its particular build, and selects the correct set for install.


This is a production release that adds utf8 locale symlinks and removes an unused auto variable from the ceil() function in the extended math library.

Users do NOT need to update unless they want the locales.


This is a production release with two small changes. Users do NOT need to upgrade to this release; however, if they haven't upgraded to 3.0.0 yet, it may be worthwhile to upgrade to this release.

The first change is fixing a compiler warning on FreeBSD with strict warnings on.

The second change is to make the new implementation of ceil() in lib2.bc much more efficient.


Notes for package maintainers:

First, the 2.7.0 release series saw a change in the option parsing. This made me change one error message and add a few others. The error message that was changed removed one format specifier. This means that printf() will seqfault on old locale files. Unfortunately, bc cannot use any locale files except the global ones that are already installed, so it will use the previous ones while running tests during install. If bc segfaults while running arg tests when updating, it is because the global locale files have not been replaced. Make sure to either prevent the test suite from running on update or remove the old locale files before updating. (Removing the locale files can be done with make uninstall or by running the script.) Once this is done, bc should install without problems.

Second, the option to build without signal support has been removed. See below for the reasons why.

This is a production release with some small bug fixes, a few improvements, three major bug fixes, and a complete redesign of bc's error and signal handling. Users and package maintainers should update to this version as soon as possible.

The first major bug fix was in how bc executed files. Previously, a whole file was parsed before it was executed, but if a function is defined after code, especially if the function definition was actually a redefinition, and the code before the definition referred to the previous function, this bc would replace the function before executing any code. The fix was to make sure that all code that existed before a function definition was executed.

The second major bug fix was in bc's lib2.bc. The ceil() function had a bug where a 0 in the decimal place after the truncation position, caused it to output the wrong numbers if there was any non-zero digit after.

The third major bug is that when passing parameters to functions, if an expression included an array (not an array element) as a parameter, it was accepted, when it should have been rejected. It is now correctly rejected.

Beyond that, this bc got several improvements that both sped it up, improved the handling of signals, and improved the error handling.

First, the requirements for bc were pushed back to POSIX 2008. bc uses one function, strdup(), which is not in POSIX 2001, and it is in the X/Open System Interfaces group 2001. It is, however, in POSIX 2008, and since POSIX 2008 is old enough to be supported anywhere that I care, that should be the requirement.

Second, the BcVm global variable was put into bss. This actually slightly reduces the size of the executable from a massive code shrink, and it will stop bc from allocating a large set of memory when bc starts.

Third, the default Karatsuba length was updated from 64 to 32 after making the optimization changes below, since 32 is going to be better than 64 after the changes.

Fourth, Spanish translations were added.

Fifth, the interpreter received a speedup to make performance on non-math-heavy scripts more competitive with GNU bc. While improvements did, in fact, get it much closer (see the benchmarks), it isn't quite there.

There were several things done to speed up the interpreter:

First, several small inefficiencies were removed. These inefficiencies included calling the function bc_vec_pop(v) twice instead of calling bc_vec_npop(v, 2). They also included an extra function call for checking the size of the stack and checking the size of the stack more than once on several operations.

Second, since the current bc function is the one that stores constants and strings, the program caches pointers to the current function's vectors of constants and strings to prevent needing to grab the current function in order to grab a constant or a string.

Third, bc tries to reuse BcNum's (the internal representation of arbitary-precision numbers). If a BcNum has the default capacity of BC_NUM_DEF_SIZE (32 on 64-bit and 16 on 32-bit) when it is freed, it is added to a list of available BcNum's. And then, when a BcNum is allocated with a capacity of BC_NUM_DEF_SIZE and any BcNum's exist on the list of reusable ones, one of those ones is grabbed instead.

In order to support these changes, the BC_NUM_DEF_SIZE was changed. It used to be 16 bytes on all systems, but it was changed to more closely align with the minimum allocation size on Linux, which is either 32 bytes (64-bit musl), 24 bytes (64-bit glibc), 16 bytes (32-bit musl), or 12 bytes (32-bit glibc). Since these are the minimum allocation sizes, these are the sizes that would be allocated anyway, making it worth it to just use the whole space, so the value of BC_NUM_DEF_SIZE on 64-bit systems was changed to 32 bytes.

On top of that, at least on 64-bit, BC_NUM_DEF_SIZE supports numbers with either 72 integer digits or 45 integer digits and 27 fractional digits. This should be more than enough for most cases since bc's default scale values are 0 or 20, meaning that, by default, it has at most 20 fractional digits. And 45 integer digits are a lot; it's enough to calculate the amount of mass in the Milky Way galaxy in kilograms. Also, 72 digits is enough to calculate the diameter of the universe in Planck lengths.

(For 32-bit, these numbers are either 32 integer digits or 12 integer digits and 20 fractional digits. These are also quite big, and going much bigger on a 32-bit system seems a little pointless since 12 digits is just under a trillion and 20 fractional digits is still enough for about any use since 10^-20 light years is just under a millimeter.)

All of this together means that for ordinary uses, and even uses in scientific work, the default number size will be all that is needed, which means that nearly all, if not all, numbers will be reused, relieving pressure on the system allocator.

I did several experiments to find the changes that had the most impact, especially with regard to reusing BcNum's. One was putting BcNum's into buckets according to their capacity in powers of 2 up to 512. That performed worse than bc did in 2.7.2. Another was putting any BcNum on the reuse list that had a capacity of BC_NUM_DEF_SIZE * 2 and reusing them for BcNum's that requested BC_NUM_DEF_SIZE. This did reduce the amount of time spent, but it also spent a lot of time in the system allocator for an unknown reason. (When using strace, a bunch more brk calls showed up.) Just reusing BcNum's that had exactly BC_NUM_DEF_SIZE capacity spent the smallest amount of time in both user and system time. This makes sense, especially with the changes to make BC_NUM_DEF_SIZE bigger on 64-bit systems, since the vast majority of numbers will only ever use numbers with a size less than or equal to BC_NUM_DEF_SIZE.

Last of all, bc's signal handling underwent a complete redesign. (This is the reason that this version is 3.0.0 and not 2.8.0.) The change was to move from a polling approach to signal handling to an interrupt-based approach.

Previously, every single loop condition had a check for signals. I suspect that this could be expensive when in tight loops.

Now, the signal handler just uses longjmp() (actually siglongjmp()) to start an unwinding of the stack until it is stopped or the stack is unwound to main(), which just returns. If bc is currently executing code that cannot be safely interrupted (according to POSIX), then signals are "locked." The signal handler checks if the lock is taken, and if it is, it just sets the status to indicate that a signal arrived. Later, when the signal lock is released, the status is checked to see if a signal came in. If so, the stack unwinding starts.

This design eliminates polling in favor of maintaining a stack of jmp_buf's. This has its own performance implications, but it gives better interaction. And the cost of pushing and popping a jmp_buf in a function is paid at most twice. Most functions do not pay that price, and most of the rest only pay it once. (There are only some 3 functions in bc that push and pop a jmp_buf twice.)

As a side effect of this change, I had to eliminate the use of stdio.h in bc because stdio does not play nice with signals and longjmp(). I implemented custom I/O buffer code that takes a fraction of the size. This means that static builds will be smaller, but non-static builds will be bigger, though they will have less linking time.

This change is also good because my history implementation was already bypassing stdio for good reasons, and unifying the architecture was a win.

Another reason for this change is that my bc should always behave correctly in the presence of signals like SIGINT, SIGTERM, and SIGQUIT. With the addition of my own I/O buffering, I needed to also make sure that the buffers were correctly flushed even when such signals happened.

For this reason, I removed the option to build without signal support.

As a nice side effect of this change, the error handling code could be changed to take advantage of the stack unwinding that signals used. This means that signals and error handling use the same code paths, which means that the stack unwinding is well-tested. (Errors are tested heavily in the test suite.)

It also means that functions do not need to return a status code that every caller needs to check. This eliminated over 100 branches that simply checked return codes and then passed that return code up the stack if necessary. The code bloat savings from this is at least 1700 bytes on x86_64, before taking into account the extra code from removing stdio.h.


This is a production release with one major bug fix.

The length() built-in function can take either a number or an array. If it takes an array, it returns the length of the array. Arrays can be passed by reference. The bug is that the length() function would not properly dereference arrays that were references. This is a bug that affects all users.



This is a production release with fixes for new locales and fixes for compiler warnings on FreeBSD.


This is a production release with a bug fix for Linux, new translations, and new features.

Bug fixes:

  • Option parsing in BC_ENV_ARGS was broken on Linux in 2.6.1 because glibc's getopt_long() is broken. To get around that, and to support long options on every platform, an adapted version of optparse was added. Now, bc does not even use getopt().
  • Parsing BC_ENV_ARGS with quotes now works. It isn't the smartest, but it does the job if there are spaces in file names.

The following new languages are supported:

  • Dutch
  • Polish
  • Russian
  • Japanes
  • Simplified Chinese

All of these translations were generated using DeepL, so improvements are welcome.

There is only one new feature: bc now has a built-in pseudo-random number generator (PRNG).

The PRNG is seeded, making it useful for applications where /dev/urandom does not work because output needs to be reproducible. However, it also uses /dev/urandom to seed itself by default, so it will start with a good seed by default.

It also outputs 32 bits on 32-bit platforms and 64 bits on 64-bit platforms, far better than the 15 bits of C's rand() and bash's $RANDOM.

In addition, the PRNG can take a bound, and when it gets a bound, it automatically adjusts to remove bias. It can also generate numbers of arbitrary size. (As of the time of release, the largest pseudo-random number generated by this bc was generated with a bound of 2^(2^20).)

IMPORTANT: read the bc manual and the dc manual to find out exactly what guarantees the PRNG provides. The underlying implementation is not guaranteed to stay the same, but the guarantees that it provides are guaranteed to stay the same regardless of the implementation.

On top of that, four functions were added to bc's extended math library to make using the PRNG easier:

  • frand(p): Generates a number between [0,1) to p decimal places.
  • ifrand(i, p): Generates an integer with bound i and adds it to frand(p).
  • srand(x): Randomizes the sign of x. In other words, it flips the sign of x with probability 0.5.
  • brand(): Returns a random boolean value (either 0 or 1).


This is a production release with a bug fix for FreeBSD.

The bug was that when bc was built without long options, it would give a fatal error on every run. This was caused by a mishandling of optind.


This release is a production release with no bugfixes. If you do not want to upgrade, you don't have to.

No source code changed; the only thing that changed was lib2.bc.

This release adds one function to the extended math library: p(x, y), which calculates x to the power of y, whether or not y is an integer. (The ^ operator can only accept integer powers.)

This release also includes a couple of small tweaks to the extended math library, mostly to fix returning numbers with too high of scale.


This release is a production release which addresses inconsistencies in the Portuguese locales. No bc code was changed.

The issues were that the ISO files used different naming, and also that the files that should have been symlinks were not. I did not catch that because GitHub rendered them the exact same way.


This release is a production release.

No code was changed, but the build system was changed to allow CFLAGS to be given to CC, like this:

CC="gcc -O3 -march=native" ./

If this happens, the flags are automatically put into CFLAGS, and the compiler is set appropriately. In the example above this means that CC will be "gcc" and CFLAGS will be "-O3 -march=native".

This behavior was added to conform to GNU autotools practices.


This is a production release which addresses portability concerns discovered in the bc build system. No bc code was changed.

  • Support for Solaris SPARC and AIX were added.
  • Minor documentations edits were performed.
  • An option for was added to disable long options if getopt_long() is missing.


This is a production release with new translations. No code changed.

The translations were contributed by bugcrazy, and they are for Portuguese, both Portugal and Brazil locales.


This is a production release primarily aimed at improving dc.

  • A couple of copy and paste errors in the dc manual were fixed.
  • dc startup was optimized by making sure it didn't have to set up bc-only things.
  • The bc && and || operators were made available to dc through the M and m commands, respectively.
  • dc macros were changed to be tail call-optimized.

The last item, tail call optimization, means that if the last thing in a macro is a call to another macro, then the old macro is popped before executing the new macro. This change was made to stop dc from consuming more and more memory as macros are executed in a loop.

The q and Q commands still respect the "hidden" macros by way of recording how many macros were removed by tail call optimization.


This is a production release meant to fix warnings in the Gentoo ebuild by making it possible to disable binary stripping. Other users do not need to upgrade.


This is a production release. It fixes a bug that caused -1000000000 < -1 to return 0. This only happened with negative numbers and only if the value on the left was more negative by a certain amount. That said, this bug is a bad bug, and needs to be fixed.



This is a production release with changes to the build system.


This release is a production release. It only has new features and performance improvements.

  1. The performance of sqrt(x) was improved.
  2. The new function root(x, n) was added to the extended math library to calculate nth roots.
  3. The new function cbrt(x) was added to the extended math library to calculate cube roots.


This is a non-critical release; it just changes the build system, and in non-breaking ways:

  1. Linked locale files were changed to link to their sources with a relative link.
  2. A bug in that caused long option parsing to fail under bash was fixed.


This release is not a critical release.

  1. A few codes were added to history.
  2. Multiplication was optimized a bit more.
  3. Addition and subtraction were both optimized a bit more.


This release contains a fix for the test suite made for Linux from Scratch: now the test suite prints pass when a test is passed.

Other than that, there is no change in this release, so distros and other users do not need to upgrade.


This release is a production release.

The following bugs were fixed:

  1. A dc bug that caused stack mishandling was fixed.
  2. A warning on OpenBSD was fixed.
  3. Bugs in ctrl+arrow operations in history were fixed.
  4. The ability to paste multiple lines in history was added.
  5. A bc bug, mishandling of array arguments to functions, was fixed.
  6. A crash caused by freeing the wrong pointer was fixed.
  7. A dc bug where strings, in a rare case, were mishandled in parsing was fixed.

In addition, the following changes were made:

  1. Division was slightly optimized.
  2. An option was added to the build to disable printing of prompts.
  3. The special case of empty arguments is now handled. This is to prevent errors in scripts that end up passing empty arguments.
  4. A harmless bug was fixed. This bug was that, with the pop instructions (mostly) removed (see below), bc would leave extra values on its stack for void functions and in a few other cases. These extra items would not affect anything put on the stack and would not cause any sort of crash or even buggy behavior, but they would cause bc to take more memory than it needed.

On top of the above changes, the following optimizations were added:

  1. The need for pop instructions in bc was removed.
  2. Extra tests on every iteration of the interpreter loop were removed.
  3. Updating function and code pointers on every iteration of the interpreter loop was changed to only updating them when necessary.
  4. Extra assignments to pointers were removed.

Altogether, these changes sped up the interpreter by around 2x.

NOTE: This is the last release with new features because this bc is now considered complete. From now on, only bug fixes and new translations will be added to this bc.


This is a production, bug-fix release.

Two bugs were fixed in this release:

  1. A rare and subtle signal handling bug was fixed.
  2. A misbehavior on 0 to a negative power was fixed.

The last bug bears some mentioning.

When I originally wrote power, I did not thoroughly check its error cases; instead, I had it check if the first number was 0 and then if so, just return 0. However, 0 to a negative power means that 1 will be divided by 0, which is an error.

I caught this, but only after I stopped being cocky. You see, sometime later, I had noticed that GNU bc returned an error, correctly, but I thought it was wrong simply because that's not what my bc did. I saw it again later and had a double take. I checked for real, finally, and found out that my bc was wrong all along.

That was bad on me. But the bug was easy to fix, so it is fixed now.

There are two other things in this release:

  1. Subtraction was optimized by Stefan Eßer.
  2. Division was also optimized, also by Stefan Eßer.


This release contains a fix for a possible overflow in the signal handling. I would be surprised if any users ran into it because it would only happen after 2 billion (2^31-1) SIGINT's, but I saw it and had to fix it.


This release contains very few things that will apply to any users.

  1. A slight bug in dc's interactive mode was fixed.
  2. A bug in the test suite that was only triggered on NetBSD was fixed.
  3. The -P/--no-prompt option was added for users that do not want a prompt.
  4. A make check target was added as an alias for make test.
  5. dc got its own read prompt: ?> .


This release is a production release.

This release is also a little different from previous releases. From here on out, I do not plan on adding any more features to this bc; I believe that it is complete. However, there may be bug fix releases in the future, if I or any others manage to find bugs.

This release has only a few new features:

  1. atan2(y, x) was added to the extended math library as both a2(y, x) and atan2(y, x).
  2. Locales were fixed.
  3. A POSIX shell-compatible script was added as an alternative to compiling gen/strgen.c on a host machine. More details about making the choice between the two can be found by running ./ --help or reading the build manual.
  4. Multiplication was optimized by using diagonal multiplication, rather than straight brute force.
  5. The script was fixed.
  6. dc was given the ability to use the environment variable DC_ENV_ARGS.
  7. dc was also given the ability to use the -i or --interactive options.
  8. Printing the prompt was fixed so that it did not print when it shouldn't.
  9. Signal handling was fixed.
  10. Handling of SIGTERM and SIGQUIT was fixed.
  11. The built-in functions maxibase(), maxobase(), and maxscale() (the commands T, U, V in dc, respectively) were added to allow scripts to query for the max allowable values of those globals.
  12. Some incompatibilities with POSIX were fixed.

In addition, this release is 2.0.0 for a big reason: the internal format for numbers changed. They used to be a char array. Now, they are an array of larger integers, packing more decimal digits into each integer. This has delivered HUGE performance improvements, especially for multiplication, division, and power.

This bc should now be the fastest bc available, but I may be wrong.


This release contains a fix for a harmless bug (it is harmless in that it still works, but it just copies extra data) in the script.


This version contains fixes for the build on Arch Linux.


This release removes the use of local in shell scripts because it's not POSIX shell-compatible, and also updates a man page that should have been updated a long time ago but was missed.


This release contains some missing locale *.msg files.


This release contains a few bug fixes and new French translations.


This release contains a fix for a bug: use of uninitialized data. Such data was only used when outputting an error message, but I am striving for perfection. As Michelangelo said, "Trifles make perfection, and perfection is no trifle."


This release contains fixes for OpenBSD.


This release contains bug fixes for some rare bugs.


This is a production release.

There have been several changes since 1.1.0:

  1. The build system had some changes.
  2. Locale support has been added. (Patches welcome for translations.)
  3. The ability to turn ibase, obase, and scale into stacks was added with the -g command-line option. (See the bc manual for more details.)
  4. Support for compiling on Mac OSX out of the box was added.
  5. The extended math library got t(x), ceil(x), and some aliases.
  6. The extended math library also got r2d(x) (for converting from radians to degrees) and d2r(x) (for converting from degrees to radians). This is to allow using degrees with the standard library.
  7. Both calculators now accept numbers in scientific notation. See the bc manual and the dc manual for details.
  8. Both calculators can output in either scientific or engineering notation. See the bc manual and the dc manual for details.
  9. Some inefficiencies were removed.
  10. Some bugs were fixed.
  11. Some bugs in the extended library were fixed.
  12. Some defects from Coverity Scan were fixed.


This release contains a fix to the build system that allows it to build on older versions of glibc.


This release contains a fix for a bug in the test suite where bc tests and dc tests could not be run in parallel.


This release has a fix for a history bug; the down arrow did not work.


This release fixes a bug in the 1.1.0 build system. The source is exactly the same.

The bug that was fixed was a failure to install if no EXECSUFFIX was used.


This is a production release. However, many new features were added since 1.0.

  1. The build system has been changed to use a custom, POSIX shell-compatible configure script ( to generate a POSIX make-compatible Makefile, which means that bc and dc now build out of the box on any POSIX-compatible system.
  2. Out-of-memory and output errors now cause the bc to report the error, clean up, and die, rather than just reporting and trying to continue.
  3. Strings and constants are now garbage collected when possible.
  4. Signal handling and checking has been made more simple and more thorough.
  5. BcGlobals was refactored into BcVm and BcVm was made global. Some procedure names were changed to reflect its difference to everything else.
  6. Addition got a speed improvement.
  7. Some common code for addition and multiplication was refactored into its own procedure.
  8. A bug was removed where dc could have been selected, but the internal #define that returned true for a query about dc would not have returned true.
  9. Useless calls to bc_num_zero() were removed.
  10. History support was added. The history support is based off of a UTF-8 aware fork of linenoise, which has been customized with bc's own data structures and signal handling.
  11. Generating C source from the math library now removes tabs from the library, shrinking the size of the executable.
  12. The math library was shrunk.
  13. Error handling and reporting was improved.
  14. Reallocations were reduced by giving access to the request size for each operation.
  15. abs() (b command for dc) was added as a builtin.
  16. Both calculators were tested on FreeBSD.
  17. Many obscure parse bugs were fixed.
  18. Markdown and man page manuals were added, and the man pages are installed by make install.
  19. Executable size was reduced, though the added features probably made the executable end up bigger.
  20. GNU-style array references were added as a supported feature.
  21. Allocations were reduced.
  22. New operators were added: $ ($ for dc), @ (@ for dc), @=, << (H for dc), <<=, >> (h for dc), and >>=. See the bc manual and the dc manual for more details.
  23. An extended math library was added. This library contains code that makes it so I can replace my desktop calculator with this bc. See the bc manual for more details.
  24. Support for all capital letters as numbers was added.
  25. Support for GNU-style void functions was added.
  26. A bug fix for improper handling of function parameters was added.
  27. Precedence for the or (||) operator was changed to match GNU bc.
  28. dc was given an explicit negation command.
  29. dc was changed to be able to handle strings in arrays.

1.1 Release Candidate 3

This release is the eighth release candidate for 1.1, though it is the third release candidate meant as a general release candidate. The new code has not been tested as thoroughly as it should for release.

1.1 Release Candidate 2

This release is the seventh release candidate for 1.1, though it is the second release candidate meant as a general release candidate. The new code has not been tested as thoroughly as it should for release.

1.1 FreeBSD Beta 5

This release is the sixth release candidate for 1.1, though it is the fifth release candidate meant specifically to test if bc works on FreeBSD. The new code has not been tested as thoroughly as it should for release.

1.1 FreeBSD Beta 4

This release is the fifth release candidate for 1.1, though it is the fourth release candidate meant specifically to test if bc works on FreeBSD. The new code has not been tested as thoroughly as it should for release.

1.1 FreeBSD Beta 3

This release is the fourth release candidate for 1.1, though it is the third release candidate meant specifically to test if bc works on FreeBSD. The new code has not been tested as thoroughly as it should for release.

1.1 FreeBSD Beta 2

This release is the third release candidate for 1.1, though it is the second release candidate meant specifically to test if bc works on FreeBSD. The new code has not been tested as thoroughly as it should for release.

1.1 FreeBSD Beta 1

This release is the second release candidate for 1.1, though it is meant specifically to test if bc works on FreeBSD. The new code has not been tested as thoroughly as it should for release.

1.1 Release Candidate 1

This is the first release candidate for 1.1. The new code has not been tested as thoroughly as it should for release.


This is the first non-beta release. bc is ready for production use.

As such, a lot has changed since 0.5.

  1. dc has been added. It has been tested even more thoroughly than bc was for 0.5. It does not have the ! command, and for security reasons, it never will, so it is complete.
  2. bc has been more thoroughly tested. An entire section of the test suite (for both programs) has been added to test for errors.
  3. A prompt (>>> ) has been added for interactive mode, making it easier to see inputs and outputs.
  4. Interrupt handling has been improved, including elimination of race conditions (as much as possible).
  5. MinGW and Windows Subsystem for Linux support has been added (see xstatic for binaries).
  6. Memory leaks and errors have been eliminated (as far as ASan and Valgrind can tell).
  7. Crashes have been eliminated (as far as afl can tell).
  8. Karatsuba multiplication was added (and thoroughly) tested, speeding up multiplication and power by orders of magnitude.
  9. Performance was further enhanced by using a "divmod" function to reduce redundant divisions and by removing superfluous memset() calls.
  10. To switch between Karatsuba and O(n^2) multiplication, the config variable BC_NUM_KARATSUBA_LEN was added. It is set to a sane default, but the optimal number can be found with (requires Python 3) and then configured through make.
  11. The random math test generator script was changed to Python 3 and improved. bc and dc have together been run through 30+ million random tests.
  12. All known math bugs have been fixed, including out of control memory allocations in sine and cosine (that was actually a parse bug), certain cases of infinite loop on square root, and slight inaccuracies (as much as possible; see the README) in transcendental functions.
  13. Parsing has been fixed as much as possible.
  14. Test coverage was improved to 94.8%. The only paths not covered are ones that happen when malloc() or realloc() fails.
  15. An extension to get the length of an array was added.
  16. The boolean not (!) had its precedence change to match negation.
  17. Data input was hardened.
  18. bc was made fully compliant with POSIX when the -s flag is used or POSIXLY_CORRECT is defined.
  19. Error handling was improved.
  20. bc now checks that files it is given are not directories.

1.0 Release Candidate 7

This is the seventh release candidate for 1.0. It fixes a few bugs in 1.0 Release Candidate 6.

1.0 Release Candidate 6

This is the sixth release candidate for 1.0. It fixes a few bugs in 1.0 Release Candidate 5.

1.0 Release Candidate 5

This is the fifth release candidate for 1.0. It fixes a few bugs in 1.0 Release Candidate 4.

1.0 Release Candidate 4

This is the fourth release candidate for 1.0. It fixes a few bugs in 1.0 Release Candidate 3.

1.0 Release Candidate 3

This is the third release candidate for 1.0. It fixes a few bugs in 1.0 Release Candidate 2.

1.0 Release Candidate 2

This is the second release candidate for 1.0. It fixes a few bugs in 1.0 Release Candidate 1.

1.0 Release Candidate 1

This is the first Release Candidate for 1.0. bc is complete, with dc, but it is not tested.


This beta release completes more features, but it is still not complete nor tested as thoroughly as necessary.


This beta release fixes a few bugs in 0.4.


This is a beta release. It does not have the complete set of features, and it is not thoroughly tested.