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Re: __typeof__ (const int)
On 2017-02-16 22:54 +0800, Xi Ruoyao wrote:
> According to the Standard, '32768' is a decimal literal, but '-32768'
> is not. It's an expression using unary '-' to the literal '32768'.
> Here '32768' has type int32_t. So the expression also has type
> int32_t despite the result can fit into an int16_t.
It's called 'literal' in C++ Standard. In C Standard it's just called
integer constant.
For example, in C99 6.4.4.1 the grammar of decimal-constant is:
decimal-constant:
nonzero-digit
decimal-constant digit
We can see a decimal constant must begin with a nonzero-digit,
'-' is not a nonzero-digit. So '-32768' is not a decimal-constant.
The description of 6.4.4.1 also said:
An integer constant begins with a digit.
--
Xi Ruoyao <ryxi@stu.xidian.edu.cn>
School of Aerospace Science and Technology, Xidian University