如何转换的32位整数到64位的值在C [英] How To Convert a 32-bit Integer into a 64 bit value In C

问题描述

我收到编译错误在项目code，其中的情况如下：

I am getting compilation error in a Project Code where the situation is as follows:

typedef unsigned int U32bit;
typedef unsigned long long U64bit;

U32bit      var;
U64bit      var2;

var = function();  /* Function returns a 32-bit value, which is stored in var */

var2 = 100*var1;   /* 100*var1 is very Big & can be stored only in U64bit variable */

For the Above Line: var2 = 100*var1

我收到以下编译错误在Solaris上：

I am getting the following Compilation Error on Solaris:

"conversion to non-scalar type requested"

我也曾尝试类型转换：

I have also tried typecasting:

var2 = (U64bit) 100*var1;

这也给出了同样的错误。

This also gives the same error.

推荐答案

标准的固定宽度整数类型 uint32_t的和 uint64_t中，尝试这些。那么该类型的常量可以用定义UINT64_C（100）。

The standard fixed-width integer types in C are uint32_t and uint64_t, try with these. Then a constant of that type can be defined with UINT64_C(100).

要拥有这些类型的，你可能必须添加

To have these types you might have to add

#include <stdint.h>

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