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This manual documents @command{bc}, an arbitrary precision calculator language.
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This manual is part of GNU @command{bc}.@*
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Copyright (C) 1991, 1992, 1993, 1994, 1997 Free Software Foundation, Inc.
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59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
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Copyright (C) 1991, 1992, 1993, 1994, 1997, 2003, 2006 Free Software Foundation, Inc.
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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Permission is granted to make and distribute verbatim copies of
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this manual provided the copyright notice and this permission notice
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are preserved on all copies.
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Permission is granted to process this file through TeX and print the
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results, provided the printed document carries copying permission
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notice identical to this one except for the removal of this paragraph
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(this paragraph not being relevant to the printed manual).
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Permission is granted to copy and distribute modified versions of this
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manual under the conditions for verbatim copying, provided that the entire
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Parameters are numbers or arrays (an extension). In the function definition,
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zero or more parameters are defined by listing their names separated by
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commas. Numbers are only call by value parameters. Arrays are only
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call by variable. Arrays are specified in the parameter definition by
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commas. All parameters are call by value parameters.
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Arrays are specified in the parameter definition by
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the notation "@var{name}@code{[ ]}". In the function call, actual parameters
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are full expressions for number parameters. The same notation is used
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for passing arrays as for defining array parameters. The named array is
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passed by variable to the function. Since function definitions are dynamic,
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passed by value to the function. Since function definitions are dynamic,
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parameter numbers and types are checked when a function is called. Any
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mismatch in number or types of parameters will cause a runtime error.
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A runtime error will also occur for the call to an undefined function.
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standard function @code{read}, which will always use the current value
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of @var{ibase} for conversion of numbers.
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As an extension, the format of the definition has been slightly relaxed.
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The standard requires the opening brace be on the same line as the
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@code{define} keyword and all other parts must be on following lines.
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This version of @command{bc} will allow any number of newlines before and
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after the opening brace of the function. For example, the following
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definitions are legal.
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Several extensions have been added to functions. First, the format of
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the definition has been slightly relaxed. The standard requires the
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opening brace be on the same line as the @code{define} keyword and all
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other parts must be on following lines. This version of @command{bc}
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will allow any number of newlines before and after the opening brace of
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the function. For example, the following definitions are legal.
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define d (n) @{ return (2*n); @}
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@{ return (2*n); @}
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Functions may be defined as @code{void}. A void
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funtion returns no value and thus may not be used in any place that needs
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a value. A void function does not produce any output when called by itself
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on an input line. The key word @code{void} is placed between the key word
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@code{define} and the function name. For example, consider the following
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define py (y) @{ print "--->", y, "<---", "\n"; @}
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define void px (x) @{ print "--->", x, "<---", "\n"; @}
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Since @code{py} is not a void function, the call of @code{py(1)} prints
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the desired output and then prints a second line that is the value of
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the function. Since the value of a function that is not given an
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explicit return statement is zero, the zero is printed. For @code{px(1)},
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no zero is printed because the function is a void function.
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Also, call by variable for arrays was added. To declare a
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call by variable array, the declaration of the array parameter in the
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function definition looks like "@code{*}@var{name}@code{[]}". The call
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to the function remains the same as call by value arrays.
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@node Math Library Functions, , Functions, Functions
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@section Math Library Functions
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@item l (@var{x})
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The natural logarithm of @var{x}.
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@item @var{e} (@var{x})
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The exponential function of raising @var{e} to the value @var{x}.
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@item @var{j} (@var{n,x})
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The bessel function of integer order @var{n} of @var{x}.
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The Bessel function of integer order @var{n} of @var{x}.
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@node Examples, Readline and Libedit Options, Functions, Top
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@node Readline and Libedit Options, GNU @command{bc} and Other Implementations, Examples, Top
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@node Readline and Libedit Options, Comparison with Other Implementations, Examples, Top
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@chapter Readline and Libedit Options
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GNU @command{bc} can be compiled (via a configure option) to use the GNU
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@command{history} and BSD @command{libedit} libraries. One can not
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enable both @command{readline} and @command{libedit} at the same time.
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@node GNU @command{bc} and Other Implementations, Limits, Readline and Libedit Options, Top
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@chapter GNU @command{bc} and Other Implementations
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@node Comparison with Other Implementations, Limits, Readline and Libedit Options, Top
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@chapter Comparison with Other Implementations
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This version of @command{bc} was implemented from the POSIX P1003.2/D11
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draft and contains several differences and extensions relative to the
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@node Limits, Environment Variables, GNU @command{bc} and Other Implementations, Top
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@node Limits, Environment Variables, Comparison with Other Implementations, Top
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The following are the limits currently in place for this @command{bc}
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@item BC_ENV_ARGS
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This is another mechanism to get arguments to @command{bc}. The format
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is the same as the command line arguments. These arguments are
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processed first, so any files listed in the environent arguments are
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processed first, so any files listed in the environment arguments are
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processed before any command line argument files. This allows the user
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to set up "standard" options and files to be processed at every
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invocation of @command{bc}. The files in the environment variables
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wants defined every time @command{bc} is run.
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@item BC_LINE_LENGTH
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This should be an integer specifing the number of characters in an
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This should be an integer specifying the number of characters in an
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output line for numbers. This includes the backslash and newline
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characters for long numbers.
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characters for long numbers. As an extension, the value of zero disables the
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multi-line feature. Any other value of this variable that is less than
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3 sets the line length to 70.
added
removed
doc/bc.texi
