Question

Can anyone explain why universal character literals (eg “\u00b1”) are being encoded into char strings as UTF-8? Why does the following print the plus/minus symbol?

#include <iostream>
#include <cstring>
int main()
{
  std::cout << "\u00b1" << std::endl;
  return 0;
}

Is this related to my current locale?

Answer 1

2.13.2. […]

5/ A universal-character-name is translated to the encoding, in
the execution character set, of the character named. If there is no
such encoding, the universal-character-name is translated to an
implementation defined encoding. [Note: in translation phase 1, a
universal-character-name is introduced whenever an actual extended
character is encountered in the source text. Therefore, all extended
characters are described in terms of universal-character-names.
However, the actual compiler implementation may use its own native
character set, so long as the same results are obtained. ]

and

2.2. […] The values of the members of the execution character sets
are implementation-defined, and any additional members are
locale-specific.

In short, the answer to your question is in your compiler documentation. However:

2.2. 2/ The character designated by the universal-character-name
\UNNNNNNNN is that character whose character short name in ISO/IEC
10646 is NNNNNNNN; the character designated by the
universal-character-name \uNNNN is that character whose character
short name in ISO/IEC 10646 is 0000NNNN. If the hexadecimal value for
a universal character name is less than 0x20 or in the range 0x7F-0x9F
(inclusive), or if the universal character name designates a character
in the basic source character set, then the program is illformed.

so you are guaranteed that the character you name is translated into an implementation defined encoding, possibly locale specific.