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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: how cast works?
Date: Thu, 08 Aug 2024 12:39:14 -0700
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Thiago Adams <thiago.adams@gmail.com> writes:
> On 07/08/2024 17:08, Keith Thompson wrote:
>> Thiago Adams <thiago.adams@gmail.com> writes:
>>> How cast works?
>>> Does it changes the memory?
>>> For instance, from "unsigned int" to "signed char".
>>> Is it just like discarding bytes or something else?
>
> I also curious about how bool works.
>
> Values converted to bool became 0 or 1.
> When this conversion happens, at read or write? Both?

I don't know what you mean by that.

A conversion takes a value of some type and yields a value of some
(other) type.  If the target type is bool, the result is false (0) if
the operand is equal to zero, true (1) otherwise.

A cast is simply an explicit conversion.  Explict and implicit
conversions do the same thing.  (Some conversions can only be done
explicitly.)

A converted value does not "become" 0 or 1; the conversion *yields*
0 or 1.  The value of (bool)42 is 1, but 42 is still 42.

> How much does it cost?

It depends on what code the compiler generates; the language doesn't
address that.  It could be free if the result isn't used and the
compiler optimizes it away.

[...]

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */