IV. BCMath Arbitrary Precision Mathematics Functions

介紹

For arbitrary precision mathematics PHP offers the Binary Calculator which supports numbers of any size and precision, represented as strings.

需求

Since PHP 4.0.4, libbcmath is bundled with PHP. You don't need any external libraries for this extension.

安裝

In PHP 4, these functions are only available if PHP was configured with --enable-bcmath. In PHP 3, these functions are only available if PHP was NOT configured with --disable-bcmath.

The windows version of PHP has built in support for this extension. You do not need to load any additional extension in order to use these functions.

執行時期組態

php.ini中的設定會影響這些函數的行為。

表格 1. BC math configuration options

NameDefaultChangeable
bcmath.scale0PHP_INI_ALL
For further details and definition of the PHP_INI_* constants see ini_set().

Here is a short explanation of the configuration directives.

bcmath.scale integer

Number of decimal digits for all bcmath functions.

資源類型

這個延伸沒有定義任何資源。

預先定義常數

這個延伸沒有定義任何常數。

內容目錄
bcadd -- Add two arbitrary precision numbers
bccomp -- Compare two arbitrary precision numbers
bcdiv -- Divide two arbitrary precision numbers
bcmod --  Get modulus of an arbitrary precision number
bcmul -- Multiply two arbitrary precision number
bcpow --  Raise an arbitrary precision number to another
bcpowmod --  Raise an arbitrary precision number to another, reduced by a specified modulus.
bcscale --  Set default scale parameter for all bc math functions
bcsqrt --  Get the square root of an arbitrary precision number
bcsub --  Subtract one arbitrary precision number from another