PHP_INT_SIZE返回4,但是我的操作系统是64位 [英] PHP_INT_SIZE returns 4 But my Operating System Is 64 bit
问题描述
我的操作系统是Windows 7和64位.
现在,我运行以下代码:
My operating System is windows 7 and 64bit.
Now I run following code:
echo PHP_INT_SIZE;//prints 4
echo PHP_INT_MAX;//prints 2147483647
但是我认为应该是8
和(2^63-1)//^ represents power
谁能解释我为什么会这样?
Can anyone explain me why this happen?
推荐答案
整数大小始终取决于编译器/解释器/平台(这也适用于其他语言).
对于Windows上的PHP,即使硬件和PHP均为64位,它也根本不支持64位整数
Integer size are always compiler/interpreter/platform dependent (this applies for other languages too).
In the case of PHP on Windows it does not support 64-bit integers at all, even if both the hardware and PHP are 64-bit
在Windows x86_64上,PHP_INT_MAX为2147483647.这是因为在基础c代码中,long是32位.
On windows x86_64, PHP_INT_MAX is 2147483647. This is because in the underlying c-code, a long is 32 bit.
x86_64上的Linux使用64位长,因此PHP_INT_MAX将为9223372036854775807.
Linux on x86_64 uses a 64bit long so PHP_INT_MAX is going to be 9223372036854775807.
如果您需要更高的精度,可以使用 GMP 或 BCMath 扩展名.
If you need a bigger precision you could use either GMP or BCMath extension.
提示:除非您确切需要代码将在哪个php版本/平台上运行,否则永远不要假设类型可以处理的最大值.
Tip: never make assumptions on the max value a type will be able to handle unless you need exactly on which php version/platform the code will run.
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