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Signedness of char and Unicode in C++0x

By : user3852207
Date : October 15 2020, 01:19 AM
To fix the issue you can do char will be the type used for UTF-8 because it's redefined to be sure it can be used with it:
code :

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Is the signedness of char an interface issue?

By : user2396224
Date : March 29 2020, 07:55 AM
To fix the issue you can do According to ISO/IEC 9899:TC3,
calling a function through an expression of incompatible type is undefined behaviour ( §9) compatible function types must have compatible parameter types ( §15) compatible pointer types must point to compatible types ( §2) char, signed char and unsigned char are different basic types (6.2.5 §14) and thus incompatible (6.2.7 §1), which is also explicitly mentioned in footnote 35 on page 35

Remove un-/signedness of char type

By : Adrian Ziemkowski
Date : March 29 2020, 07:55 AM
help you fix your problem The "sign-ness" of char is implementation defined. It doesn't have to be able to store negative numbers. In strict standardese, char even is never a signed integer type, even if it can store negative numbers on an implementation. Still, the class template is_signed will report true for char if it can store negative numbers, because that's a useful thing for it to do.
Anyway, the boost docs say the following about make_unsigned, making it look like you can use it for your purpose.

C cast and char signedness

By : Eytyixs
Date : March 29 2020, 07:55 AM
will help you So lately, I read on an issue regarding the three distinct types in C, char/unsigned char/signed char. The problem that I now encounter is not something I have experienced up till now (my program works correctly on all tested computers and only targets little-endian (basically all modern desktops and servers using Windows/Linux right?). I frequently reuse a char array I defined for holding a "string" (not a real string of course) as temporary variables. E.g. instead of adding another char to the stack I just reuse one of the members like array[0]. However, I based this tactic on the fact that a char would always be signed, until I read today that it actually depends on the implementation. What will happen if I now have a char and I assign a negative value to it? , The following code prints No:
code :
#include <stdio.h>

    unsigned char a;

    a = -1;

    if(a == -1)

    return 0;
`(int)a == -1`

The signedness of char in g++/gcc and its history

By : Sushant
Date : March 29 2020, 07:55 AM
To fix this issue I see no undefined behavior in your program. Negative array indices are not necessarily invalid, as long as the result of adding the index to the prefix refers to a valid memory location. (A negative array index is invalid (i.e., has undefined behavior) if the prefix is the name of an array object or a pointer to the 0th element of an array object, but that's not the case here.)
In this case, aptr points to element 256 of a 512-element array, so the valid indices go from -256 to +255 (+256 yields a valid address just past the end of the array, but it can't be dereferenced). Assuming CHAR_BIT==8, any of signed char, unsigned char, or plain char has a range that's a subset of the array's valid index range.
code :
aptr[0] = 0xFF;

Issues about the signedness of char

By : Angel
Date : March 29 2020, 07:55 AM
will help you 1) testing MSB: (x | 0x7F) != 0x7F (or reinterpret_cast(x) & 0x80)
2) reinterpret_cast(x) = 0xFF;
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