无符号 __int128 文字 GCC

Question

我有一个函数foo(unsigned __int128)。如何将 unsigned __int128 类型的文字传递给函数？我的尝试：

   foo(0xFFFFFFFFFFFFFF23FFFFF); //Truncated (expected)
   foo(0xFFFFFFFFFFFFFFF01FFFu); //Truncated (expected)
   foo(0xFFFFFFFFFFFFFFF23FFFFull); //Truncated
   foo((unsigned __int128)0xFF45FFFFFFFFFFFFFFFFFull); //Truncated

如您所见，所有这些都被截断了。我如何向 GCC 发出信号，即文字是 unsigned __int128?

编辑： gcc 手册说：

There is no support in GCC for expressing an integer constant of type __int128 for targets with long long integer less than 128 bits wide

这是否意味着我无法编写类型为（无符号）__int128 的文字？

有其他选择吗？

Answer 1

来自https://gcc.gnu.org/onlinedocs/gcc/_005f_005fint128.html

6.9 128-bit Integers

As an extension the integer scalar type __int128 is supported for targets which have an integer mode wide enough to hold 128 bits. Simply write __int128 for a signed 128-bit integer, or unsigned __int128 for an unsigned 128-bit integer. There is no support in GCC for expressing an integer constant of type __int128 for targets with long long integer less than 128 bits wide.

所以，不，你不能有一个文字 128 位常量

无符号 __int128 文字 GCC

Unsigned __int128 literal GCC

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gcc

int128