Re: [PATCH 4/7] xdiff: make fields of xrecord_t Rust friendly

From: Collin Funk <collin.funk1@gmail.com>
Date: Jul 28, 2025, 20:00 UTC
Message-ID: <87ecu0nl0q.fsf@gmail.com>
In-Reply-To: <CAH=ZcbCnEpBokM9rxmmkeM9GT948n7+RipXODHLfPssuwJuVCw@mail.gmail.com>

Ezekiel Newren <ezekielnewren@gmail.com> writes:

> Rust defines char as 32 bits. C treats char as signed 8 bits. What git
> really means by char* is treat everything like a byte string, and u8
> is how raw bytes are handled in Rust.

Minor correction, but the C standard leaves the signedness of 'char' up to the implementation. Portable code must be written to assume a plain 'char' can be signed or unsigned.

Using the test program below:

    #include <stdio.h>
    #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
    int
    main (void)
    {
      printf ("%d\n", TYPE_SIGNED (char));
      return 0;
    }

On GNU/Linux x86_64:

    $ ./a.out 
    1

On GNU/Linux aarch64:

    $ ./a.out 
    0

Collin

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