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diff --git a/static/freebsd/man1/A.1 b/static/freebsd/man1/A.1 new file mode 100644 index 00000000..50c14dd4 --- /dev/null +++ b/static/freebsd/man1/A.1 @@ -0,0 +1,1695 @@ +.\" +.\" SPDX-License-Identifier: BSD-2-Clause +.\" +.\" Copyright (c) 2018-2025 Gavin D. Howard and contributors. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions are met: +.\" +.\" * Redistributions of source code must retain the above copyright notice, +.\" this list of conditions and the following disclaimer. +.\" +.\" * Redistributions in binary form must reproduce the above copyright notice, +.\" this list of conditions and the following disclaimer in the documentation +.\" and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +.\" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE +.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +.\" POSSIBILITY OF SUCH DAMAGE. +.\" +.TH "DC" "1" "August 2024" "Gavin D. Howard" "General Commands Manual" +.nh +.ad l +.SH Name +dc \- arbitrary\-precision decimal reverse\-Polish notation calculator +.SH SYNOPSIS +\f[B]dc\f[R] [\f[B]\-cChiPRvVx\f[R]] [\f[B]\-\-version\f[R]] +[\f[B]\-\-help\f[R]] [\f[B]\-\-digit\-clamp\f[R]] +[\f[B]\-\-no\-digit\-clamp\f[R]] [\f[B]\-\-interactive\f[R]] +[\f[B]\-\-no\-prompt\f[R]] [\f[B]\-\-no\-read\-prompt\f[R]] +[\f[B]\-\-extended\-register\f[R]] [\f[B]\-e\f[R] \f[I]expr\f[R]] +[\f[B]\-\-expression\f[R]=\f[I]expr\f[R]\&...] +[\f[B]\-f\f[R] \f[I]file\f[R]\&...] +[\f[B]\-\-file\f[R]=\f[I]file\f[R]\&...] +[\f[I]file\f[R]\&...] +[\f[B]\-I\f[R] \f[I]ibase\f[R]] [\f[B]\-\-ibase\f[R]=\f[I]ibase\f[R]] +[\f[B]\-O\f[R] \f[I]obase\f[R]] [\f[B]\-\-obase\f[R]=\f[I]obase\f[R]] +[\f[B]\-S\f[R] \f[I]scale\f[R]] [\f[B]\-\-scale\f[R]=\f[I]scale\f[R]] +[\f[B]\-E\f[R] \f[I]seed\f[R]] [\f[B]\-\-seed\f[R]=\f[I]seed\f[R]] +.SH DESCRIPTION +dc(1) is an arbitrary\-precision calculator. +It uses a stack (reverse Polish notation) to store numbers and results +of computations. +Arithmetic operations pop arguments off of the stack and push the +results. +.PP +If no files are given on the command\-line, then dc(1) reads from +\f[B]stdin\f[R] (see the \f[B]STDIN\f[R] section). +Otherwise, those files are processed, and dc(1) will then exit. +.PP +If a user wants to set up a standard environment, they can use +\f[B]DC_ENV_ARGS\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +For example, if a user wants the \f[B]scale\f[R] always set to +\f[B]10\f[R], they can set \f[B]DC_ENV_ARGS\f[R] to \f[B]\-e 10k\f[R], +and this dc(1) will always start with a \f[B]scale\f[R] of \f[B]10\f[R]. +.SH OPTIONS +The following are the options that dc(1) accepts. +.TP +\f[B]\-C\f[R], \f[B]\-\-no\-digit\-clamp\f[R] +Disables clamping of digits greater than or equal to the current +\f[B]ibase\f[R] when parsing numbers. +.RS +.PP +This means that the value added to a number from a digit is always that +digit\[cq]s value multiplied by the value of ibase raised to the power +of the digit\[cq]s position, which starts from 0 at the least +significant digit. +.PP +If this and/or the \f[B]\-c\f[R] or \f[B]\-\-digit\-clamp\f[R] options +are given multiple times, the last one given is used. +.PP +This option overrides the \f[B]DC_DIGIT_CLAMP\f[R] environment variable +(see the \f[B]ENVIRONMENT VARIABLES\f[R] section) and the default, which +can be queried with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-c\f[R], \f[B]\-\-digit\-clamp\f[R] +Enables clamping of digits greater than or equal to the current +\f[B]ibase\f[R] when parsing numbers. +.RS +.PP +This means that digits that the value added to a number from a digit +that is greater than or equal to the ibase is the value of ibase minus 1 +all multiplied by the value of ibase raised to the power of the +digit\[cq]s position, which starts from 0 at the least significant +digit. +.PP +If this and/or the \f[B]\-C\f[R] or \f[B]\-\-no\-digit\-clamp\f[R] +options are given multiple times, the last one given is used. +.PP +This option overrides the \f[B]DC_DIGIT_CLAMP\f[R] environment variable +(see the \f[B]ENVIRONMENT VARIABLES\f[R] section) and the default, which +can be queried with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-E\f[R] \f[I]seed\f[R], \f[B]\-\-seed\f[R]=\f[I]seed\f[R] +Sets the builtin variable \f[B]seed\f[R] to the value \f[I]seed\f[R] +assuming that \f[I]seed\f[R] is in base 10. +It is a fatal error if \f[I]seed\f[R] is not a valid number. +.RS +.PP +If multiple instances of this option are given, the last is used. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-e\f[R] \f[I]expr\f[R], \f[B]\-\-expression\f[R]=\f[I]expr\f[R] +Evaluates \f[I]expr\f[R]. +If multiple expressions are given, they are evaluated in order. +If files are given as well (see below), the expressions and files are +evaluated in the order given. +This means that if a file is given before an expression, the file is +read in and evaluated first. +.RS +.PP +If this option is given on the command\-line (i.e., not in +\f[B]DC_ENV_ARGS\f[R], see the \f[B]ENVIRONMENT VARIABLES\f[R] section), +then after processing all expressions and files, dc(1) will exit, unless +\f[B]\-\f[R] (\f[B]stdin\f[R]) was given as an argument at least once to +\f[B]\-f\f[R] or \f[B]\-\-file\f[R], whether on the command\-line or in +\f[B]DC_ENV_ARGS\f[R]. +However, if any other \f[B]\-e\f[R], \f[B]\-\-expression\f[R], +\f[B]\-f\f[R], or \f[B]\-\-file\f[R] arguments are given after +\f[B]\-f\-\f[R] or equivalent is given, dc(1) will give a fatal error +and exit. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-f\f[R] \f[I]file\f[R], \f[B]\-\-file\f[R]=\f[I]file\f[R] +Reads in \f[I]file\f[R] and evaluates it, line by line, as though it +were read through \f[B]stdin\f[R]. +If expressions are also given (see above), the expressions are evaluated +in the order given. +.RS +.PP +If this option is given on the command\-line (i.e., not in +\f[B]DC_ENV_ARGS\f[R], see the \f[B]ENVIRONMENT VARIABLES\f[R] section), +then after processing all expressions and files, dc(1) will exit, unless +\f[B]\-\f[R] (\f[B]stdin\f[R]) was given as an argument at least once to +\f[B]\-f\f[R] or \f[B]\-\-file\f[R]. +However, if any other \f[B]\-e\f[R], \f[B]\-\-expression\f[R], +\f[B]\-f\f[R], or \f[B]\-\-file\f[R] arguments are given after +\f[B]\-f\-\f[R] or equivalent is given, dc(1) will give a fatal error +and exit. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-h\f[R], \f[B]\-\-help\f[R] +Prints a usage message and exits. +.TP +\f[B]\-I\f[R] \f[I]ibase\f[R], \f[B]\-\-ibase\f[R]=\f[I]ibase\f[R] +Sets the builtin variable \f[B]ibase\f[R] to the value \f[I]ibase\f[R] +assuming that \f[I]ibase\f[R] is in base 10. +It is a fatal error if \f[I]ibase\f[R] is not a valid number. +.RS +.PP +If multiple instances of this option are given, the last is used. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-i\f[R], \f[B]\-\-interactive\f[R] +Forces interactive mode. +(See the \f[B]INTERACTIVE MODE\f[R] section.) +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-L\f[R], \f[B]\-\-no\-line\-length\f[R] +Disables line length checking and prints numbers without backslashes and +newlines. +In other words, this option sets \f[B]BC_LINE_LENGTH\f[R] to \f[B]0\f[R] +(see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-O\f[R] \f[I]obase\f[R], \f[B]\-\-obase\f[R]=\f[I]obase\f[R] +Sets the builtin variable \f[B]obase\f[R] to the value \f[I]obase\f[R] +assuming that \f[I]obase\f[R] is in base 10. +It is a fatal error if \f[I]obase\f[R] is not a valid number. +.RS +.PP +If multiple instances of this option are given, the last is used. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-P\f[R], \f[B]\-\-no\-prompt\f[R] +Disables the prompt in TTY mode. +(The prompt is only enabled in TTY mode. +See the \f[B]TTY MODE\f[R] section.) +This is mostly for those users that do not want a prompt or are not used +to having them in dc(1). +Most of those users would want to put this option in +\f[B]DC_ENV_ARGS\f[R]. +.RS +.PP +These options override the \f[B]DC_PROMPT\f[R] and \f[B]DC_TTY_MODE\f[R] +environment variables (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-R\f[R], \f[B]\-\-no\-read\-prompt\f[R] +Disables the read prompt in TTY mode. +(The read prompt is only enabled in TTY mode. +See the \f[B]TTY MODE\f[R] section.) +This is mostly for those users that do not want a read prompt or are not +used to having them in dc(1). +Most of those users would want to put this option in +\f[B]BC_ENV_ARGS\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +This option is also useful in hash bang lines of dc(1) scripts that +prompt for user input. +.RS +.PP +This option does not disable the regular prompt because the read prompt +is only used when the \f[B]?\f[R] command is used. +.PP +These options \f[I]do\f[R] override the \f[B]DC_PROMPT\f[R] and +\f[B]DC_TTY_MODE\f[R] environment variables (see the \f[B]ENVIRONMENT +VARIABLES\f[R] section), but only for the read prompt. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-S\f[R] \f[I]scale\f[R], \f[B]\-\-scale\f[R]=\f[I]scale\f[R] +Sets the builtin variable \f[B]scale\f[R] to the value \f[I]scale\f[R] +assuming that \f[I]scale\f[R] is in base 10. +It is a fatal error if \f[I]scale\f[R] is not a valid number. +.RS +.PP +If multiple instances of this option are given, the last is used. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-v\f[R], \f[B]\-V\f[R], \f[B]\-\-version\f[R] +Print the version information (copyright header) and exits. +.TP +\f[B]\-x\f[R] \f[B]\-\-extended\-register\f[R] +Enables extended register mode. +See the \f[I]Extended Register Mode\f[R] subsection of the +\f[B]REGISTERS\f[R] section for more information. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\-z\f[R], \f[B]\-\-leading\-zeroes\f[R] +Makes dc(1) print all numbers greater than \f[B]\-1\f[R] and less than +\f[B]1\f[R], and not equal to \f[B]0\f[R], with a leading zero. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.PP +All long options are \f[B]non\-portable extensions\f[R]. +.SH STDIN +If no files are given on the command\-line and no files or expressions +are given by the \f[B]\-f\f[R], \f[B]\-\-file\f[R], \f[B]\-e\f[R], or +\f[B]\-\-expression\f[R] options, then dc(1) reads from \f[B]stdin\f[R]. +.PP +However, there is a caveat to this. +.PP +First, \f[B]stdin\f[R] is evaluated a line at a time. +The only exception to this is if a string has been finished, but not +ended. +This means that, except for escaped brackets, all brackets must be +balanced before dc(1) parses and executes. +.SH STDOUT +Any non\-error output is written to \f[B]stdout\f[R]. +In addition, if history (see the \f[B]HISTORY\f[R] section) and the +prompt (see the \f[B]TTY MODE\f[R] section) are enabled, both are output +to \f[B]stdout\f[R]. +.PP +\f[B]Note\f[R]: Unlike other dc(1) implementations, this dc(1) will +issue a fatal error (see the \f[B]EXIT STATUS\f[R] section) if it cannot +write to \f[B]stdout\f[R], so if \f[B]stdout\f[R] is closed, as in +\f[B]dc >&\-\f[R], it will quit with an error. +This is done so that dc(1) can report problems when \f[B]stdout\f[R] is +redirected to a file. +.PP +If there are scripts that depend on the behavior of other dc(1) +implementations, it is recommended that those scripts be changed to +redirect \f[B]stdout\f[R] to \f[B]/dev/null\f[R]. +.SH STDERR +Any error output is written to \f[B]stderr\f[R]. +.PP +\f[B]Note\f[R]: Unlike other dc(1) implementations, this dc(1) will +issue a fatal error (see the \f[B]EXIT STATUS\f[R] section) if it cannot +write to \f[B]stderr\f[R], so if \f[B]stderr\f[R] is closed, as in +\f[B]dc 2>&\-\f[R], it will quit with an error. +This is done so that dc(1) can exit with an error code when +\f[B]stderr\f[R] is redirected to a file. +.PP +If there are scripts that depend on the behavior of other dc(1) +implementations, it is recommended that those scripts be changed to +redirect \f[B]stderr\f[R] to \f[B]/dev/null\f[R]. +.SH SYNTAX +Each item in the input source code, either a number (see the +\f[B]NUMBERS\f[R] section) or a command (see the \f[B]COMMANDS\f[R] +section), is processed and executed, in order. +Input is processed immediately when entered. +.PP +\f[B]ibase\f[R] is a register (see the \f[B]REGISTERS\f[R] section) that +determines how to interpret constant numbers. +It is the \[lq]input\[rq] base, or the number base used for interpreting +input numbers. +\f[B]ibase\f[R] is initially \f[B]10\f[R]. +The max allowable value for \f[B]ibase\f[R] is \f[B]16\f[R]. +The min allowable value for \f[B]ibase\f[R] is \f[B]2\f[R]. +The max allowable value for \f[B]ibase\f[R] can be queried in dc(1) +programs with the \f[B]T\f[R] command. +.PP +\f[B]obase\f[R] is a register (see the \f[B]REGISTERS\f[R] section) that +determines how to output results. +It is the \[lq]output\[rq] base, or the number base used for outputting +numbers. +\f[B]obase\f[R] is initially \f[B]10\f[R]. +The max allowable value for \f[B]obase\f[R] is \f[B]DC_BASE_MAX\f[R] and +can be queried with the \f[B]U\f[R] command. +The min allowable value for \f[B]obase\f[R] is \f[B]0\f[R]. +If \f[B]obase\f[R] is \f[B]0\f[R], values are output in scientific +notation, and if \f[B]obase\f[R] is \f[B]1\f[R], values are output in +engineering notation. +Otherwise, values are output in the specified base. +.PP +Outputting in scientific and engineering notations are +\f[B]non\-portable extensions\f[R]. +.PP +The \f[I]scale\f[R] of an expression is the number of digits in the +result of the expression right of the decimal point, and \f[B]scale\f[R] +is a register (see the \f[B]REGISTERS\f[R] section) that sets the +precision of any operations (with exceptions). +\f[B]scale\f[R] is initially \f[B]0\f[R]. +\f[B]scale\f[R] cannot be negative. +The max allowable value for \f[B]scale\f[R] can be queried in dc(1) +programs with the \f[B]V\f[R] command. +.PP +\f[B]seed\f[R] is a register containing the current seed for the +pseudo\-random number generator. +If the current value of \f[B]seed\f[R] is queried and stored, then if it +is assigned to \f[B]seed\f[R] later, the pseudo\-random number generator +is guaranteed to produce the same sequence of pseudo\-random numbers +that were generated after the value of \f[B]seed\f[R] was first queried. +.PP +Multiple values assigned to \f[B]seed\f[R] can produce the same sequence +of pseudo\-random numbers. +Likewise, when a value is assigned to \f[B]seed\f[R], it is not +guaranteed that querying \f[B]seed\f[R] immediately after will return +the same value. +In addition, the value of \f[B]seed\f[R] will change after any call to +the \f[B]\[cq]\f[R] command or the \f[B]\[lq]\f[R] command that does not +get receive a value of \f[B]0\f[R] or \f[B]1\f[R]. +The maximum integer returned by the \f[B]\[cq]\f[R] command can be +queried with the \f[B]W\f[R] command. +.PP +\f[B]Note\f[R]: The values returned by the pseudo\-random number +generator with the \f[B]\[cq]\f[R] and \f[B]\[lq]\f[R] commands are +guaranteed to \f[B]NOT\f[R] be cryptographically secure. +This is a consequence of using a seeded pseudo\-random number generator. +However, they \f[I]are\f[R] guaranteed to be reproducible with identical +\f[B]seed\f[R] values. +This means that the pseudo\-random values from dc(1) should only be used +where a reproducible stream of pseudo\-random numbers is +\f[I]ESSENTIAL\f[R]. +In any other case, use a non\-seeded pseudo\-random number generator. +.PP +The pseudo\-random number generator, \f[B]seed\f[R], and all associated +operations are \f[B]non\-portable extensions\f[R]. +.SS Comments +Comments go from \f[B]#\f[R] until, and not including, the next newline. +This is a \f[B]non\-portable extension\f[R]. +.SH NUMBERS +Numbers are strings made up of digits, uppercase letters up to +\f[B]F\f[R], and at most \f[B]1\f[R] period for a radix. +Numbers can have up to \f[B]DC_NUM_MAX\f[R] digits. +Uppercase letters are equal to \f[B]9\f[R] plus their position in the +alphabet (i.e., \f[B]A\f[R] equals \f[B]10\f[R], or \f[B]9+1\f[R]). +.PP +If a digit or letter makes no sense with the current value of +\f[B]ibase\f[R] (i.e., they are greater than or equal to the current +value of \f[B]ibase\f[R]), then the behavior depends on the existence of +the \f[B]\-c\f[R]/\f[B]\-\-digit\-clamp\f[R] or +\f[B]\-C\f[R]/\f[B]\-\-no\-digit\-clamp\f[R] options (see the +\f[B]OPTIONS\f[R] section), the existence and setting of the +\f[B]DC_DIGIT_CLAMP\f[R] environment variable (see the \f[B]ENVIRONMENT +VARIABLES\f[R] section), or the default, which can be queried with the +\f[B]\-h\f[R]/\f[B]\-\-help\f[R] option. +.PP +If clamping is off, then digits or letters that are greater than or +equal to the current value of \f[B]ibase\f[R] are not changed. +Instead, their given value is multiplied by the appropriate power of +\f[B]ibase\f[R] and added into the number. +This means that, with an \f[B]ibase\f[R] of \f[B]3\f[R], the number +\f[B]AB\f[R] is equal to \f[B]3\[ha]1*A+3\[ha]0*B\f[R], which is +\f[B]3\f[R] times \f[B]10\f[R] plus \f[B]11\f[R], or \f[B]41\f[R]. +.PP +If clamping is on, then digits or letters that are greater than or equal +to the current value of \f[B]ibase\f[R] are set to the value of the +highest valid digit in \f[B]ibase\f[R] before being multiplied by the +appropriate power of \f[B]ibase\f[R] and added into the number. +This means that, with an \f[B]ibase\f[R] of \f[B]3\f[R], the number +\f[B]AB\f[R] is equal to \f[B]3\[ha]1*2+3\[ha]0*2\f[R], which is +\f[B]3\f[R] times \f[B]2\f[R] plus \f[B]2\f[R], or \f[B]8\f[R]. +.PP +There is one exception to clamping: single\-character numbers (i.e., +\f[B]A\f[R] alone). +Such numbers are never clamped and always take the value they would have +in the highest possible \f[B]ibase\f[R]. +This means that \f[B]A\f[R] alone always equals decimal \f[B]10\f[R] and +\f[B]Z\f[R] alone always equals decimal \f[B]35\f[R]. +This behavior is mandated by the standard for bc(1) (see the STANDARDS +section) and is meant to provide an easy way to set the current +\f[B]ibase\f[R] (with the \f[B]i\f[R] command) regardless of the current +value of \f[B]ibase\f[R]. +.PP +If clamping is on, and the clamped value of a character is needed, use a +leading zero, i.e., for \f[B]A\f[R], use \f[B]0A\f[R]. +.PP +In addition, dc(1) accepts numbers in scientific notation. +These have the form \f[B]<number>e<integer>\f[R]. +The exponent (the portion after the \f[B]e\f[R]) must be an integer. +An example is \f[B]1.89237e9\f[R], which is equal to +\f[B]1892370000\f[R]. +Negative exponents are also allowed, so \f[B]4.2890e_3\f[R] is equal to +\f[B]0.0042890\f[R]. +.PP +\f[B]WARNING\f[R]: Both the number and the exponent in scientific +notation are interpreted according to the current \f[B]ibase\f[R], but +the number is still multiplied by \f[B]10\[ha]exponent\f[R] regardless +of the current \f[B]ibase\f[R]. +For example, if \f[B]ibase\f[R] is \f[B]16\f[R] and dc(1) is given the +number string \f[B]FFeA\f[R], the resulting decimal number will be +\f[B]2550000000000\f[R], and if dc(1) is given the number string +\f[B]10e_4\f[R], the resulting decimal number will be \f[B]0.0016\f[R]. +.PP +Accepting input as scientific notation is a \f[B]non\-portable +extension\f[R]. +.SH COMMANDS +The valid commands are listed below. +.SS Printing +These commands are used for printing. +.PP +Note that both scientific notation and engineering notation are +available for printing numbers. +Scientific notation is activated by assigning \f[B]0\f[R] to +\f[B]obase\f[R] using \f[B]0o\f[R], and engineering notation is +activated by assigning \f[B]1\f[R] to \f[B]obase\f[R] using +\f[B]1o\f[R]. +To deactivate them, just assign a different value to \f[B]obase\f[R]. +.PP +Printing numbers in scientific notation and/or engineering notation is a +\f[B]non\-portable extension\f[R]. +.TP +\f[B]p\f[R] +Prints the value on top of the stack, whether number or string, and +prints a newline after. +.RS +.PP +This does not alter the stack. +.RE +.TP +\f[B]n\f[R] +Prints the value on top of the stack, whether number or string, and pops +it off of the stack. +.TP +\f[B]P\f[R] +Pops a value off the stack. +.RS +.PP +If the value is a number, it is truncated and the absolute value of the +result is printed as though \f[B]obase\f[R] is \f[B]256\f[R] and each +digit is interpreted as an 8\-bit ASCII character, making it a byte +stream. +.PP +If the value is a string, it is printed without a trailing newline. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]f\f[R] +Prints the entire contents of the stack, in order from newest to oldest, +without altering anything. +.RS +.PP +Users should use this command when they get lost. +.RE +.SS Arithmetic +These are the commands used for arithmetic. +.TP +\f[B]+\f[R] +The top two values are popped off the stack, added, and the result is +pushed onto the stack. +The \f[I]scale\f[R] of the result is equal to the max \f[I]scale\f[R] of +both operands. +.TP +\f[B]\-\f[R] +The top two values are popped off the stack, subtracted, and the result +is pushed onto the stack. +The \f[I]scale\f[R] of the result is equal to the max \f[I]scale\f[R] of +both operands. +.TP +\f[B]*\f[R] +The top two values are popped off the stack, multiplied, and the result +is pushed onto the stack. +If \f[B]a\f[R] is the \f[I]scale\f[R] of the first expression and +\f[B]b\f[R] is the \f[I]scale\f[R] of the second expression, the +\f[I]scale\f[R] of the result is equal to +\f[B]min(a+b,max(scale,a,b))\f[R] where \f[B]min()\f[R] and +\f[B]max()\f[R] return the obvious values. +.TP +\f[B]/\f[R] +The top two values are popped off the stack, divided, and the result is +pushed onto the stack. +The \f[I]scale\f[R] of the result is equal to \f[B]scale\f[R]. +.RS +.PP +The first value popped off of the stack must be non\-zero. +.RE +.TP +\f[B]%\f[R] +The top two values are popped off the stack, remaindered, and the result +is pushed onto the stack. +.RS +.PP +Remaindering is equivalent to 1) Computing \f[B]a/b\f[R] to current +\f[B]scale\f[R], and 2) Using the result of step 1 to calculate +\f[B]a\-(a/b)*b\f[R] to \f[I]scale\f[R] +\f[B]max(scale+scale(b),scale(a))\f[R]. +.PP +The first value popped off of the stack must be non\-zero. +.RE +.TP +\f[B]\[ti]\f[R] +The top two values are popped off the stack, divided and remaindered, +and the results (divided first, remainder second) are pushed onto the +stack. +This is equivalent to \f[B]x y / x y %\f[R] except that \f[B]x\f[R] and +\f[B]y\f[R] are only evaluated once. +.RS +.PP +The first value popped off of the stack must be non\-zero. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\[ha]\f[R] +The top two values are popped off the stack, the second is raised to the +power of the first, and the result is pushed onto the stack. +The \f[I]scale\f[R] of the result is equal to \f[B]scale\f[R]. +.RS +.PP +The first value popped off of the stack must be an integer, and if that +value is negative, the second value popped off of the stack must be +non\-zero. +.RE +.TP +\f[B]v\f[R] +The top value is popped off the stack, its square root is computed, and +the result is pushed onto the stack. +The \f[I]scale\f[R] of the result is equal to \f[B]scale\f[R]. +.RS +.PP +The value popped off of the stack must be non\-negative. +.RE +.TP +\f[B]_\f[R] +If this command \f[I]immediately\f[R] precedes a number (i.e., no spaces +or other commands), then that number is input as a negative number. +.RS +.PP +Otherwise, the top value on the stack is popped and copied, and the copy +is negated and pushed onto the stack. +This behavior without a number is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]b\f[R] +The top value is popped off the stack, and if it is zero, it is pushed +back onto the stack. +Otherwise, its absolute value is pushed onto the stack. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]|\f[R] +The top three values are popped off the stack, a modular exponentiation +is computed, and the result is pushed onto the stack. +.RS +.PP +The first value popped is used as the reduction modulus and must be an +integer and non\-zero. +The second value popped is used as the exponent and must be an integer +and non\-negative. +The third value popped is the base and must be an integer. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]$\f[R] +The top value is popped off the stack and copied, and the copy is +truncated and pushed onto the stack. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\[at]\f[R] +The top two values are popped off the stack, and the precision of the +second is set to the value of the first, whether by truncation or +extension. +.RS +.PP +The first value popped off of the stack must be an integer and +non\-negative. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]H\f[R] +The top two values are popped off the stack, and the second is shifted +left (radix shifted right) to the value of the first. +.RS +.PP +The first value popped off of the stack must be an integer and +non\-negative. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]h\f[R] +The top two values are popped off the stack, and the second is shifted +right (radix shifted left) to the value of the first. +.RS +.PP +The first value popped off of the stack must be an integer and +non\-negative. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]G\f[R] +The top two values are popped off of the stack, they are compared, and a +\f[B]1\f[R] is pushed if they are equal, or \f[B]0\f[R] otherwise. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]N\f[R] +The top value is popped off of the stack, and if it a \f[B]0\f[R], a +\f[B]1\f[R] is pushed; otherwise, a \f[B]0\f[R] is pushed. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B](\f[R] +The top two values are popped off of the stack, they are compared, and a +\f[B]1\f[R] is pushed if the first is less than the second, or +\f[B]0\f[R] otherwise. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]{\f[R] +The top two values are popped off of the stack, they are compared, and a +\f[B]1\f[R] is pushed if the first is less than or equal to the second, +or \f[B]0\f[R] otherwise. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B])\f[R] +The top two values are popped off of the stack, they are compared, and a +\f[B]1\f[R] is pushed if the first is greater than the second, or +\f[B]0\f[R] otherwise. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]}\f[R] +The top two values are popped off of the stack, they are compared, and a +\f[B]1\f[R] is pushed if the first is greater than or equal to the +second, or \f[B]0\f[R] otherwise. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]M\f[R] +The top two values are popped off of the stack. +If they are both non\-zero, a \f[B]1\f[R] is pushed onto the stack. +If either of them is zero, or both of them are, then a \f[B]0\f[R] is +pushed onto the stack. +.RS +.PP +This is like the \f[B]&&\f[R] operator in bc(1), and it is \f[I]not\f[R] +a short\-circuit operator. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]m\f[R] +The top two values are popped off of the stack. +If at least one of them is non\-zero, a \f[B]1\f[R] is pushed onto the +stack. +If both of them are zero, then a \f[B]0\f[R] is pushed onto the stack. +.RS +.PP +This is like the \f[B]||\f[R] operator in bc(1), and it is \f[I]not\f[R] +a short\-circuit operator. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.SS Pseudo\-Random Number Generator +dc(1) has a built\-in pseudo\-random number generator. +These commands query the pseudo\-random number generator. +(See Parameters for more information about the \f[B]seed\f[R] value that +controls the pseudo\-random number generator.) +.PP +The pseudo\-random number generator is guaranteed to \f[B]NOT\f[R] be +cryptographically secure. +.TP +\f[B]\[cq]\f[R] +Generates an integer between 0 and \f[B]DC_RAND_MAX\f[R], inclusive (see +the \f[B]LIMITS\f[R] section). +.RS +.PP +The generated integer is made as unbiased as possible, subject to the +limitations of the pseudo\-random number generator. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]\[lq]\f[R] +Pops a value off of the stack, which is used as an \f[B]exclusive\f[R] +upper bound on the integer that will be generated. +If the bound is negative or is a non\-integer, an error is raised, and +dc(1) resets (see the \f[B]RESET\f[R] section) while \f[B]seed\f[R] +remains unchanged. +If the bound is larger than \f[B]DC_RAND_MAX\f[R], the higher bound is +honored by generating several pseudo\-random integers, multiplying them +by appropriate powers of \f[B]DC_RAND_MAX+1\f[R], and adding them +together. +Thus, the size of integer that can be generated with this command is +unbounded. +Using this command will change the value of \f[B]seed\f[R], unless the +operand is \f[B]0\f[R] or \f[B]1\f[R]. +In that case, \f[B]0\f[R] is pushed onto the stack, and \f[B]seed\f[R] +is \f[I]not\f[R] changed. +.RS +.PP +The generated integer is made as unbiased as possible, subject to the +limitations of the pseudo\-random number generator. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.SS Stack Control +These commands control the stack. +.TP +\f[B]c\f[R] +Removes all items from (\[lq]clears\[rq]) the stack. +.TP +\f[B]d\f[R] +Copies the item on top of the stack (\[lq]duplicates\[rq]) and pushes +the copy onto the stack. +.TP +\f[B]r\f[R] +Swaps (\[lq]reverses\[rq]) the two top items on the stack. +.TP +\f[B]R\f[R] +Pops (\[lq]removes\[rq]) the top value from the stack. +.SS Register Control +These commands control registers (see the \f[B]REGISTERS\f[R] section). +.TP +\f[B]s\f[R]\f[I]r\f[R] +Pops the value off the top of the stack and stores it into register +\f[I]r\f[R]. +.TP +\f[B]l\f[R]\f[I]r\f[R] +Copies the value in register \f[I]r\f[R] and pushes it onto the stack. +This does not alter the contents of \f[I]r\f[R]. +.TP +\f[B]S\f[R]\f[I]r\f[R] +Pops the value off the top of the (main) stack and pushes it onto the +stack of register \f[I]r\f[R]. +The previous value of the register becomes inaccessible. +.TP +\f[B]L\f[R]\f[I]r\f[R] +Pops the value off the top of the stack for register \f[I]r\f[R] and +push it onto the main stack. +The previous value in the stack for register \f[I]r\f[R], if any, is now +accessible via the \f[B]l\f[R]\f[I]r\f[R] command. +.SS Parameters +These commands control the values of \f[B]ibase\f[R], \f[B]obase\f[R], +\f[B]scale\f[R], and \f[B]seed\f[R]. +Also see the \f[B]SYNTAX\f[R] section. +.TP +\f[B]i\f[R] +Pops the value off of the top of the stack and uses it to set +\f[B]ibase\f[R], which must be between \f[B]2\f[R] and \f[B]16\f[R], +inclusive. +.RS +.PP +If the value on top of the stack has any \f[I]scale\f[R], the +\f[I]scale\f[R] is ignored. +.RE +.TP +\f[B]o\f[R] +Pops the value off of the top of the stack and uses it to set +\f[B]obase\f[R], which must be between \f[B]0\f[R] and +\f[B]DC_BASE_MAX\f[R], inclusive (see the \f[B]LIMITS\f[R] section and +the \f[B]NUMBERS\f[R] section). +.RS +.PP +If the value on top of the stack has any \f[I]scale\f[R], the +\f[I]scale\f[R] is ignored. +.RE +.TP +\f[B]k\f[R] +Pops the value off of the top of the stack and uses it to set +\f[B]scale\f[R], which must be non\-negative. +.RS +.PP +If the value on top of the stack has any \f[I]scale\f[R], the +\f[I]scale\f[R] is ignored. +.RE +.TP +\f[B]j\f[R] +Pops the value off of the top of the stack and uses it to set +\f[B]seed\f[R]. +The meaning of \f[B]seed\f[R] is dependent on the current pseudo\-random +number generator but is guaranteed to not change except for new major +versions. +.RS +.PP +The \f[I]scale\f[R] and sign of the value may be significant. +.PP +If a previously used \f[B]seed\f[R] value is used again, the +pseudo\-random number generator is guaranteed to produce the same +sequence of pseudo\-random numbers as it did when the \f[B]seed\f[R] +value was previously used. +.PP +The exact value assigned to \f[B]seed\f[R] is not guaranteed to be +returned if the \f[B]J\f[R] command is used. +However, if \f[B]seed\f[R] \f[I]does\f[R] return a different value, both +values, when assigned to \f[B]seed\f[R], are guaranteed to produce the +same sequence of pseudo\-random numbers. +This means that certain values assigned to \f[B]seed\f[R] will not +produce unique sequences of pseudo\-random numbers. +.PP +There is no limit to the length (number of significant decimal digits) +or \f[I]scale\f[R] of the value that can be assigned to \f[B]seed\f[R]. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]I\f[R] +Pushes the current value of \f[B]ibase\f[R] onto the main stack. +.TP +\f[B]O\f[R] +Pushes the current value of \f[B]obase\f[R] onto the main stack. +.TP +\f[B]K\f[R] +Pushes the current value of \f[B]scale\f[R] onto the main stack. +.TP +\f[B]J\f[R] +Pushes the current value of \f[B]seed\f[R] onto the main stack. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]T\f[R] +Pushes the maximum allowable value of \f[B]ibase\f[R] onto the main +stack. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]U\f[R] +Pushes the maximum allowable value of \f[B]obase\f[R] onto the main +stack. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]V\f[R] +Pushes the maximum allowable value of \f[B]scale\f[R] onto the main +stack. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]W\f[R] +Pushes the maximum (inclusive) integer that can be generated with the +\f[B]\[cq]\f[R] pseudo\-random number generator command. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.SS Strings +The following commands control strings. +.PP +dc(1) can work with both numbers and strings, and registers (see the +\f[B]REGISTERS\f[R] section) can hold both strings and numbers. +dc(1) always knows whether the contents of a register are a string or a +number. +.PP +While arithmetic operations have to have numbers, and will print an +error if given a string, other commands accept strings. +.PP +Strings can also be executed as macros. +For example, if the string \f[B][1pR]\f[R] is executed as a macro, then +the code \f[B]1pR\f[R] is executed, meaning that the \f[B]1\f[R] will be +printed with a newline after and then popped from the stack. +.TP +\f[B][\f[R]\f[I]characters\f[R]\f[B]]\f[R] +Makes a string containing \f[I]characters\f[R] and pushes it onto the +stack. +.RS +.PP +If there are brackets (\f[B][\f[R] and \f[B]]\f[R]) in the string, then +they must be balanced. +Unbalanced brackets can be escaped using a backslash (\f[B]\[rs]\f[R]) +character. +.PP +If there is a backslash character in the string, the character after it +(even another backslash) is put into the string verbatim, but the +(first) backslash is not. +.RE +.TP +\f[B]a\f[R] +The value on top of the stack is popped. +.RS +.PP +If it is a number, it is truncated and its absolute value is taken. +The result mod \f[B]256\f[R] is calculated. +If that result is \f[B]0\f[R], push an empty string; otherwise, push a +one\-character string where the character is the result of the mod +interpreted as an ASCII character. +.PP +If it is a string, then a new string is made. +If the original string is empty, the new string is empty. +If it is not, then the first character of the original string is used to +create the new string as a one\-character string. +The new string is then pushed onto the stack. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]x\f[R] +Pops a value off of the top of the stack. +.RS +.PP +If it is a number, it is pushed back onto the stack. +.PP +If it is a string, it is executed as a macro. +.PP +This behavior is the norm whenever a macro is executed, whether by this +command or by the conditional execution commands below. +.RE +.TP +\f[B]>\f[R]\f[I]r\f[R] +Pops two values off of the stack that must be numbers and compares them. +If the first value is greater than the second, then the contents of +register \f[I]r\f[R] are executed. +.RS +.PP +For example, \f[B]0 1>a\f[R] will execute the contents of register +\f[B]a\f[R], and \f[B]1 0>a\f[R] will not. +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.RE +.TP +\f[B]>\f[R]\f[I]r\f[R]\f[B]e\f[R]\f[I]s\f[R] +Like the above, but will execute register \f[I]s\f[R] if the comparison +fails. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]!>\f[R]\f[I]r\f[R] +Pops two values off of the stack that must be numbers and compares them. +If the first value is not greater than the second (less than or equal +to), then the contents of register \f[I]r\f[R] are executed. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.RE +.TP +\f[B]!>\f[R]\f[I]r\f[R]\f[B]e\f[R]\f[I]s\f[R] +Like the above, but will execute register \f[I]s\f[R] if the comparison +fails. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]<\f[R]\f[I]r\f[R] +Pops two values off of the stack that must be numbers and compares them. +If the first value is less than the second, then the contents of +register \f[I]r\f[R] are executed. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.RE +.TP +\f[B]<\f[R]\f[I]r\f[R]\f[B]e\f[R]\f[I]s\f[R] +Like the above, but will execute register \f[I]s\f[R] if the comparison +fails. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]!<\f[R]\f[I]r\f[R] +Pops two values off of the stack that must be numbers and compares them. +If the first value is not less than the second (greater than or equal +to), then the contents of register \f[I]r\f[R] are executed. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.RE +.TP +\f[B]!<\f[R]\f[I]r\f[R]\f[B]e\f[R]\f[I]s\f[R] +Like the above, but will execute register \f[I]s\f[R] if the comparison +fails. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]=\f[R]\f[I]r\f[R] +Pops two values off of the stack that must be numbers and compares them. +If the first value is equal to the second, then the contents of register +\f[I]r\f[R] are executed. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.RE +.TP +\f[B]=\f[R]\f[I]r\f[R]\f[B]e\f[R]\f[I]s\f[R] +Like the above, but will execute register \f[I]s\f[R] if the comparison +fails. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]!=\f[R]\f[I]r\f[R] +Pops two values off of the stack that must be numbers and compares them. +If the first value is not equal to the second, then the contents of +register \f[I]r\f[R] are executed. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.RE +.TP +\f[B]!=\f[R]\f[I]r\f[R]\f[B]e\f[R]\f[I]s\f[R] +Like the above, but will execute register \f[I]s\f[R] if the comparison +fails. +.RS +.PP +If either or both of the values are not numbers, dc(1) will raise an +error and reset (see the \f[B]RESET\f[R] section). +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]?\f[R] +Reads a line from the \f[B]stdin\f[R] and executes it. +This is to allow macros to request input from users. +.TP +\f[B]q\f[R] +During execution of a macro, this exits the execution of that macro and +the execution of the macro that executed it. +If there are no macros, or only one macro executing, dc(1) exits. +.TP +\f[B]Q\f[R] +Pops a value from the stack which must be non\-negative and is used the +number of macro executions to pop off of the execution stack. +If the number of levels to pop is greater than the number of executing +macros, dc(1) exits. +.TP +\f[B],\f[R] +Pushes the depth of the execution stack onto the stack. +The execution stack is the stack of string executions. +The number that is pushed onto the stack is exactly as many as is needed +to make dc(1) exit with the \f[B]Q\f[R] command, so the sequence +\f[B],Q\f[R] will make dc(1) exit. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.SS Status +These commands query status of the stack or its top value. +.TP +\f[B]Z\f[R] +Pops a value off of the stack. +.RS +.PP +If it is a number, calculates the number of significant decimal digits +it has and pushes the result. +It will push \f[B]1\f[R] if the argument is \f[B]0\f[R] with no decimal +places. +.PP +If it is a string, pushes the number of characters the string has. +.RE +.TP +\f[B]X\f[R] +Pops a value off of the stack. +.RS +.PP +If it is a number, pushes the \f[I]scale\f[R] of the value onto the +stack. +.PP +If it is a string, pushes \f[B]0\f[R]. +.RE +.TP +\f[B]u\f[R] +Pops one value off of the stack. +If the value is a number, this pushes \f[B]1\f[R] onto the stack. +Otherwise (if it is a string), it pushes \f[B]0\f[R]. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]t\f[R] +Pops one value off of the stack. +If the value is a string, this pushes \f[B]1\f[R] onto the stack. +Otherwise (if it is a number), it pushes \f[B]0\f[R]. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.TP +\f[B]z\f[R] +Pushes the current depth of the stack (before execution of this command) +onto the stack. +.TP +\f[B]y\f[R]\f[I]r\f[R] +Pushes the current stack depth of the register \f[I]r\f[R] onto the main +stack. +.RS +.PP +Because each register has a depth of \f[B]1\f[R] (with the value +\f[B]0\f[R] in the top item) when dc(1) starts, dc(1) requires that each +register\[cq]s stack must always have at least one item; dc(1) will give +an error and reset otherwise (see the \f[B]RESET\f[R] section). +This means that this command will never push \f[B]0\f[R]. +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.SS Arrays +These commands manipulate arrays. +.TP +\f[B]:\f[R]\f[I]r\f[R] +Pops the top two values off of the stack. +The second value will be stored in the array \f[I]r\f[R] (see the +\f[B]REGISTERS\f[R] section), indexed by the first value. +.TP +\f[B];\f[R]\f[I]r\f[R] +Pops the value on top of the stack and uses it as an index into the +array \f[I]r\f[R]. +The selected value is then pushed onto the stack. +.TP +\f[B]Y\f[R]\f[I]r\f[R] +Pushes the length of the array \f[I]r\f[R] onto the stack. +.RS +.PP +This is a \f[B]non\-portable extension\f[R]. +.RE +.SS Global Settings +These commands retrieve global settings. +These are the only commands that require multiple specific characters, +and all of them begin with the letter \f[B]g\f[R]. +Only the characters below are allowed after the character \f[B]g\f[R]; +any other character produces a parse error (see the \f[B]ERRORS\f[R] +section). +.TP +\f[B]gl\f[R] +Pushes the line length set by \f[B]DC_LINE_LENGTH\f[R] (see the +\f[B]ENVIRONMENT VARIABLES\f[R] section) onto the stack. +.TP +\f[B]gx\f[R] +Pushes \f[B]1\f[R] onto the stack if extended register mode is on, +\f[B]0\f[R] otherwise. +See the \f[I]Extended Register Mode\f[R] subsection of the +\f[B]REGISTERS\f[R] section for more information. +.TP +\f[B]gz\f[R] +Pushes \f[B]0\f[R] onto the stack if the leading zero setting has not +been enabled with the \f[B]\-z\f[R] or \f[B]\-\-leading\-zeroes\f[R] +options (see the \f[B]OPTIONS\f[R] section), non\-zero otherwise. +.SH REGISTERS +Registers are names that can store strings, numbers, and arrays. +(Number/string registers do not interfere with array registers.) +.PP +Each register is also its own stack, so the current register value is +the top of the stack for the register. +All registers, when first referenced, have one value (\f[B]0\f[R]) in +their stack, and it is a runtime error to attempt to pop that item off +of the register stack. +.PP +In non\-extended register mode, a register name is just the single +character that follows any command that needs a register name. +The only exceptions are: a newline (\f[B]`\[rs]n'\f[R]) and a left +bracket (\f[B]`['\f[R]); it is a parse error for a newline or a left +bracket to be used as a register name. +.SS Extended Register Mode +Unlike most other dc(1) implentations, this dc(1) provides nearly +unlimited amounts of registers, if extended register mode is enabled. +.PP +If extended register mode is enabled (\f[B]\-x\f[R] or +\f[B]\-\-extended\-register\f[R] command\-line arguments are given), +then normal single character registers are used \f[I]unless\f[R] the +character immediately following a command that needs a register name is +a space (according to \f[B]isspace()\f[R]) and not a newline +(\f[B]`\[rs]n'\f[R]). +.PP +In that case, the register name is found according to the regex +\f[B][a\-z][a\-z0\-9_]*\f[R] (like bc(1) identifiers), and it is a parse +error if the next non\-space characters do not match that regex. +.SH RESET +When dc(1) encounters an error or a signal that it has a non\-default +handler for, it resets. +This means that several things happen. +.PP +First, any macros that are executing are stopped and popped off the +execution stack. +The behavior is not unlike that of exceptions in programming languages. +Then the execution point is set so that any code waiting to execute +(after all macros returned) is skipped. +.PP +However, the stack of values is \f[I]not\f[R] cleared; in interactive +mode, users can inspect the stack and manipulate it. +.PP +Thus, when dc(1) resets, it skips any remaining code waiting to be +executed. +Then, if it is interactive mode, and the error was not a fatal error +(see the \f[B]EXIT STATUS\f[R] section), it asks for more input; +otherwise, it exits with the appropriate return code. +.SH PERFORMANCE +Most dc(1) implementations use \f[B]char\f[R] types to calculate the +value of \f[B]1\f[R] decimal digit at a time, but that can be slow. +This dc(1) does something different. +.PP +It uses large integers to calculate more than \f[B]1\f[R] decimal digit +at a time. +If built in a environment where \f[B]DC_LONG_BIT\f[R] (see the +\f[B]LIMITS\f[R] section) is \f[B]64\f[R], then each integer has +\f[B]9\f[R] decimal digits. +If built in an environment where \f[B]DC_LONG_BIT\f[R] is \f[B]32\f[R] +then each integer has \f[B]4\f[R] decimal digits. +This value (the number of decimal digits per large integer) is called +\f[B]DC_BASE_DIGS\f[R]. +.PP +In addition, this dc(1) uses an even larger integer for overflow +checking. +This integer type depends on the value of \f[B]DC_LONG_BIT\f[R], but is +always at least twice as large as the integer type used to store digits. +.SH LIMITS +The following are the limits on dc(1): +.TP +\f[B]DC_LONG_BIT\f[R] +The number of bits in the \f[B]long\f[R] type in the environment where +dc(1) was built. +This determines how many decimal digits can be stored in a single large +integer (see the \f[B]PERFORMANCE\f[R] section). +.TP +\f[B]DC_BASE_DIGS\f[R] +The number of decimal digits per large integer (see the +\f[B]PERFORMANCE\f[R] section). +Depends on \f[B]DC_LONG_BIT\f[R]. +.TP +\f[B]DC_BASE_POW\f[R] +The max decimal number that each large integer can store (see +\f[B]DC_BASE_DIGS\f[R]) plus \f[B]1\f[R]. +Depends on \f[B]DC_BASE_DIGS\f[R]. +.TP +\f[B]DC_OVERFLOW_MAX\f[R] +The max number that the overflow type (see the \f[B]PERFORMANCE\f[R] +section) can hold. +Depends on \f[B]DC_LONG_BIT\f[R]. +.TP +\f[B]DC_BASE_MAX\f[R] +The maximum output base. +Set at \f[B]DC_BASE_POW\f[R]. +.TP +\f[B]DC_DIM_MAX\f[R] +The maximum size of arrays. +Set at \f[B]SIZE_MAX\-1\f[R]. +.TP +\f[B]DC_SCALE_MAX\f[R] +The maximum \f[B]scale\f[R]. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. +.TP +\f[B]DC_STRING_MAX\f[R] +The maximum length of strings. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. +.TP +\f[B]DC_NAME_MAX\f[R] +The maximum length of identifiers. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. +.TP +\f[B]DC_NUM_MAX\f[R] +The maximum length of a number (in decimal digits), which includes +digits after the decimal point. +Set at \f[B]DC_OVERFLOW_MAX\-1\f[R]. +.TP +\f[B]DC_RAND_MAX\f[R] +The maximum integer (inclusive) returned by the \f[B]\[cq]\f[R] command, +if dc(1). +Set at \f[B]2\[ha]DC_LONG_BIT\-1\f[R]. +.TP +Exponent +The maximum allowable exponent (positive or negative). +Set at \f[B]DC_OVERFLOW_MAX\f[R]. +.TP +Number of vars +The maximum number of vars/arrays. +Set at \f[B]SIZE_MAX\-1\f[R]. +.PP +These limits are meant to be effectively non\-existent; the limits are +so large (at least on 64\-bit machines) that there should not be any +point at which they become a problem. +In fact, memory should be exhausted before these limits should be hit. +.SH ENVIRONMENT VARIABLES +As \f[B]non\-portable extensions\f[R], dc(1) recognizes the following +environment variables: +.TP +\f[B]DC_ENV_ARGS\f[R] +This is another way to give command\-line arguments to dc(1). +They should be in the same format as all other command\-line arguments. +These are always processed first, so any files given in +\f[B]DC_ENV_ARGS\f[R] will be processed before arguments and files given +on the command\-line. +This gives the user the ability to set up \[lq]standard\[rq] options and +files to be used at every invocation. +The most useful thing for such files to contain would be useful +functions that the user might want every time dc(1) runs. +Another use would be to use the \f[B]\-e\f[R] option to set +\f[B]scale\f[R] to a value other than \f[B]0\f[R]. +.RS +.PP +The code that parses \f[B]DC_ENV_ARGS\f[R] will correctly handle quoted +arguments, but it does not understand escape sequences. +For example, the string \f[B]\[lq]/home/gavin/some dc file.dc\[rq]\f[R] +will be correctly parsed, but the string \f[B]\[lq]/home/gavin/some +\[dq]dc\[dq] file.dc\[rq]\f[R] will include the backslashes. +.PP +The quote parsing will handle either kind of quotes, \f[B]\[cq]\f[R] or +\f[B]\[lq]\f[R]. +Thus, if you have a file with any number of single quotes in the name, +you can use double quotes as the outside quotes, as in \f[B]\[lq]some +`dc' file.dc\[rq]\f[R], and vice versa if you have a file with double +quotes. +However, handling a file with both kinds of quotes in +\f[B]DC_ENV_ARGS\f[R] is not supported due to the complexity of the +parsing, though such files are still supported on the command\-line +where the parsing is done by the shell. +.RE +.TP +\f[B]DC_LINE_LENGTH\f[R] +If this environment variable exists and contains an integer that is +greater than \f[B]1\f[R] and is less than \f[B]UINT16_MAX\f[R] +(\f[B]2\[ha]16\-1\f[R]), dc(1) will output lines to that length, +including the backslash newline combo. +The default line length is \f[B]70\f[R]. +.RS +.PP +The special value of \f[B]0\f[R] will disable line length checking and +print numbers without regard to line length and without backslashes and +newlines. +.RE +.TP +\f[B]DC_SIGINT_RESET\f[R] +If dc(1) is not in interactive mode (see the \f[B]INTERACTIVE MODE\f[R] +section), then this environment variable has no effect because dc(1) +exits on \f[B]SIGINT\f[R] when not in interactive mode. +.RS +.PP +However, when dc(1) is in interactive mode, then if this environment +variable exists and contains an integer, a non\-zero value makes dc(1) +reset on \f[B]SIGINT\f[R], rather than exit, and zero makes dc(1) exit. +If this environment variable exists and is \f[I]not\f[R] an integer, +then dc(1) will exit on \f[B]SIGINT\f[R]. +.PP +This environment variable overrides the default, which can be queried +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.RE +.TP +\f[B]DC_TTY_MODE\f[R] +If TTY mode is \f[I]not\f[R] available (see the \f[B]TTY MODE\f[R] +section), then this environment variable has no effect. +.RS +.PP +However, when TTY mode is available, then if this environment variable +exists and contains an integer, then a non\-zero value makes dc(1) use +TTY mode, and zero makes dc(1) not use TTY mode. +.PP +This environment variable overrides the default, which can be queried +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.RE +.TP +\f[B]DC_PROMPT\f[R] +If TTY mode is \f[I]not\f[R] available (see the \f[B]TTY MODE\f[R] +section), then this environment variable has no effect. +.RS +.PP +However, when TTY mode is available, then if this environment variable +exists and contains an integer, a non\-zero value makes dc(1) use a +prompt, and zero or a non\-integer makes dc(1) not use a prompt. +If this environment variable does not exist and \f[B]DC_TTY_MODE\f[R] +does, then the value of the \f[B]DC_TTY_MODE\f[R] environment variable +is used. +.PP +This environment variable and the \f[B]DC_TTY_MODE\f[R] environment +variable override the default, which can be queried with the +\f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.RE +.TP +\f[B]DC_EXPR_EXIT\f[R] +If any expressions or expression files are given on the command\-line +with \f[B]\-e\f[R], \f[B]\-\-expression\f[R], \f[B]\-f\f[R], or +\f[B]\-\-file\f[R], then if this environment variable exists and +contains an integer, a non\-zero value makes dc(1) exit after executing +the expressions and expression files, and a zero value makes dc(1) not +exit. +.RS +.PP +This environment variable overrides the default, which can be queried +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.RE +.TP +\f[B]DC_DIGIT_CLAMP\f[R] +When parsing numbers and if this environment variable exists and +contains an integer, a non\-zero value makes dc(1) clamp digits that are +greater than or equal to the current \f[B]ibase\f[R] so that all such +digits are considered equal to the \f[B]ibase\f[R] minus 1, and a zero +value disables such clamping so that those digits are always equal to +their value, which is multiplied by the power of the \f[B]ibase\f[R]. +.RS +.PP +This never applies to single\-digit numbers, as per the bc(1) standard +(see the \f[B]STANDARDS\f[R] section). +.PP +This environment variable overrides the default, which can be queried +with the \f[B]\-h\f[R] or \f[B]\-\-help\f[R] options. +.RE +.SH EXIT STATUS +dc(1) returns the following exit statuses: +.TP +\f[B]0\f[R] +No error. +.TP +\f[B]1\f[R] +A math error occurred. +This follows standard practice of using \f[B]1\f[R] for expected errors, +since math errors will happen in the process of normal execution. +.RS +.PP +Math errors include divide by \f[B]0\f[R], taking the square root of a +negative number, using a negative number as a bound for the +pseudo\-random number generator, attempting to convert a negative number +to a hardware integer, overflow when converting a number to a hardware +integer, overflow when calculating the size of a number, and attempting +to use a non\-integer where an integer is required. +.PP +Converting to a hardware integer happens for the second operand of the +power (\f[B]\[ha]\f[R]), places (\f[B]\[at]\f[R]), left shift +(\f[B]H\f[R]), and right shift (\f[B]h\f[R]) operators. +.RE +.TP +\f[B]2\f[R] +A parse error occurred. +.RS +.PP +Parse errors include unexpected \f[B]EOF\f[R], using an invalid +character, failing to find the end of a string or comment, and using a +token where it is invalid. +.RE +.TP +\f[B]3\f[R] +A runtime error occurred. +.RS +.PP +Runtime errors include assigning an invalid number to any global +(\f[B]ibase\f[R], \f[B]obase\f[R], or \f[B]scale\f[R]), giving a bad +expression to a \f[B]read()\f[R] call, calling \f[B]read()\f[R] inside +of a \f[B]read()\f[R] call, type errors (including attempting to execute +a number), and attempting an operation when the stack has too few +elements. +.RE +.TP +\f[B]4\f[R] +A fatal error occurred. +.RS +.PP +Fatal errors include memory allocation errors, I/O errors, failing to +open files, attempting to use files that do not have only ASCII +characters (dc(1) only accepts ASCII characters), attempting to open a +directory as a file, and giving invalid command\-line options. +.RE +.PP +The exit status \f[B]4\f[R] is special; when a fatal error occurs, dc(1) +always exits and returns \f[B]4\f[R], no matter what mode dc(1) is in. +.PP +The other statuses will only be returned when dc(1) is not in +interactive mode (see the \f[B]INTERACTIVE MODE\f[R] section), since +dc(1) resets its state (see the \f[B]RESET\f[R] section) and accepts +more input when one of those errors occurs in interactive mode. +This is also the case when interactive mode is forced by the +\f[B]\-i\f[R] flag or \f[B]\-\-interactive\f[R] option. +.PP +These exit statuses allow dc(1) to be used in shell scripting with error +checking, and its normal behavior can be forced by using the +\f[B]\-i\f[R] flag or \f[B]\-\-interactive\f[R] option. +.SH INTERACTIVE MODE +Like bc(1), dc(1) has an interactive mode and a non\-interactive mode. +Interactive mode is turned on automatically when both \f[B]stdin\f[R] +and \f[B]stdout\f[R] are hooked to a terminal, but the \f[B]\-i\f[R] +flag and \f[B]\-\-interactive\f[R] option can turn it on in other +situations. +.PP +In interactive mode, dc(1) attempts to recover from errors (see the +\f[B]RESET\f[R] section), and in normal execution, flushes +\f[B]stdout\f[R] as soon as execution is done for the current input. +dc(1) may also reset on \f[B]SIGINT\f[R] instead of exit, depending on +the contents of, or default for, the \f[B]DC_SIGINT_RESET\f[R] +environment variable (see the \f[B]ENVIRONMENT VARIABLES\f[R] section). +.SH TTY MODE +If \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are all +connected to a TTY, then \[lq]TTY mode\[rq] is considered to be +available, and thus, dc(1) can turn on TTY mode, subject to some +settings. +.PP +If there is the environment variable \f[B]DC_TTY_MODE\f[R] in the +environment (see the \f[B]ENVIRONMENT VARIABLES\f[R] section), then if +that environment variable contains a non\-zero integer, dc(1) will turn +on TTY mode when \f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] +are all connected to a TTY. +If the \f[B]DC_TTY_MODE\f[R] environment variable exists but is +\f[I]not\f[R] a non\-zero integer, then dc(1) will not turn TTY mode on. +.PP +If the environment variable \f[B]DC_TTY_MODE\f[R] does \f[I]not\f[R] +exist, the default setting is used. +The default setting can be queried with the \f[B]\-h\f[R] or +\f[B]\-\-help\f[R] options. +.PP +TTY mode is different from interactive mode because interactive mode is +required in the bc(1) specification (see the \f[B]STANDARDS\f[R] +section), and interactive mode requires only \f[B]stdin\f[R] and +\f[B]stdout\f[R] to be connected to a terminal. +.SS Command\-Line History +Command\-line history is only enabled if TTY mode is, i.e., that +\f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are connected to +a TTY and the \f[B]DC_TTY_MODE\f[R] environment variable (see the +\f[B]ENVIRONMENT VARIABLES\f[R] section) and its default do not disable +TTY mode. +See the \f[B]COMMAND LINE HISTORY\f[R] section for more information. +.SS Prompt +If TTY mode is available, then a prompt can be enabled. +Like TTY mode itself, it can be turned on or off with an environment +variable: \f[B]DC_PROMPT\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] +section). +.PP +If the environment variable \f[B]DC_PROMPT\f[R] exists and is a +non\-zero integer, then the prompt is turned on when \f[B]stdin\f[R], +\f[B]stdout\f[R], and \f[B]stderr\f[R] are connected to a TTY and the +\f[B]\-P\f[R] and \f[B]\-\-no\-prompt\f[R] options were not used. +The read prompt will be turned on under the same conditions, except that +the \f[B]\-R\f[R] and \f[B]\-\-no\-read\-prompt\f[R] options must also +not be used. +.PP +However, if \f[B]DC_PROMPT\f[R] does not exist, the prompt can be +enabled or disabled with the \f[B]DC_TTY_MODE\f[R] environment variable, +the \f[B]\-P\f[R] and \f[B]\-\-no\-prompt\f[R] options, and the +\f[B]\-R\f[R] and \f[B]\-\-no\-read\-prompt\f[R] options. +See the \f[B]ENVIRONMENT VARIABLES\f[R] and \f[B]OPTIONS\f[R] sections +for more details. +.SH SIGNAL HANDLING +Sending a \f[B]SIGINT\f[R] will cause dc(1) to do one of two things. +.PP +If dc(1) is not in interactive mode (see the \f[B]INTERACTIVE MODE\f[R] +section), or the \f[B]DC_SIGINT_RESET\f[R] environment variable (see the +\f[B]ENVIRONMENT VARIABLES\f[R] section), or its default, is either not +an integer or it is zero, dc(1) will exit. +.PP +However, if dc(1) is in interactive mode, and the +\f[B]DC_SIGINT_RESET\f[R] or its default is an integer and non\-zero, +then dc(1) will stop executing the current input and reset (see the +\f[B]RESET\f[R] section) upon receiving a \f[B]SIGINT\f[R]. +.PP +Note that \[lq]current input\[rq] can mean one of two things. +If dc(1) is processing input from \f[B]stdin\f[R] in interactive mode, +it will ask for more input. +If dc(1) is processing input from a file in interactive mode, it will +stop processing the file and start processing the next file, if one +exists, or ask for input from \f[B]stdin\f[R] if no other file exists. +.PP +This means that if a \f[B]SIGINT\f[R] is sent to dc(1) as it is +executing a file, it can seem as though dc(1) did not respond to the +signal since it will immediately start executing the next file. +This is by design; most files that users execute when interacting with +dc(1) have function definitions, which are quick to parse. +If a file takes a long time to execute, there may be a bug in that file. +The rest of the files could still be executed without problem, allowing +the user to continue. +.PP +\f[B]SIGTERM\f[R] and \f[B]SIGQUIT\f[R] cause dc(1) to clean up and +exit, and it uses the default handler for all other signals. +The one exception is \f[B]SIGHUP\f[R]; in that case, and only when dc(1) +is in TTY mode (see the \f[B]TTY MODE\f[R] section), a \f[B]SIGHUP\f[R] +will cause dc(1) to clean up and exit. +.SH COMMAND LINE HISTORY +dc(1) supports interactive command\-line editing. +.PP +If dc(1) can be in TTY mode (see the \f[B]TTY MODE\f[R] section), +history can be enabled. +This means that command\-line history can only be enabled when +\f[B]stdin\f[R], \f[B]stdout\f[R], and \f[B]stderr\f[R] are all +connected to a TTY. +.PP +Like TTY mode itself, it can be turned on or off with the environment +variable \f[B]DC_TTY_MODE\f[R] (see the \f[B]ENVIRONMENT VARIABLES\f[R] +section). +.PP +\f[B]Note\f[R]: tabs are converted to 8 spaces. +.SH LOCALES +This dc(1) ships with support for adding error messages for different +locales and thus, supports \f[B]LC_MESSAGES\f[R]. +.SH SEE ALSO +bc(1) +.SH STANDARDS +The dc(1) utility operators and some behavior are compliant with the +operators in the IEEE Std 1003.1\-2017 (\[lq]POSIX.1\-2017\[rq]) bc(1) +specification at +https://pubs.opengroup.org/onlinepubs/9699919799/utilities/bc.html . +.SH BUGS +None are known. +Report bugs at https://github.com/gavinhoward/bc . +.SH AUTHOR +Gavin D. Howard \c +.MT gavin@gavinhoward.com +.ME \c +\ and contributors. |