소개
These functions allow you to work with arbitrary-length integers
using the GNU MP library.
These functions have been added in PHP 4.0.4.
Note:
Most GMP functions accept GMP number arguments. These are shown in this
documentation as GMP objects; however note that PHP
5.5 and earlier represented GMP numbers as resources. Most
of these functions will also accept numeric and string arguments, so long
as it is possible to convert the latter to a number. Also, if there is a
faster function that can operate on integer arguments, it would be used
instead of the slower function when the supplied arguments are integers.
This is done transparently, so the bottom line is that you can use
integers in every function that expects GMP number. See also the
gmp_init() function.
Note:
From PHP 5.6 onwards, you can use
arithmetic,
bitwise and
comparison operators
with the GMP objects returned from
gmp_init() and other GMP functions.
Warning
If you want to explicitly specify a large integer,
specify it as a string. If you don't do that, PHP will
interpret the integer-literal first, possibly resulting
in loss of precision, even before GMP
comes into play.
Note:
This extension is available on Windows platforms since PHP 5.1.0.