Subject: Re: [PATCH v2 3/6] bswap.h: Define GIT_LITTLE_ENDIAN on msvc as little endian

From: Junio C Hamano <[email-masked]>
Date: Thu, 12 Jun 2025 13:11:27 -0700

Sebastian Andrzej Siewior <[email-masked]> writes:

> The Microsoft Visual C++ (MSVC) compiler (as of Visual Studio 2022
> version 17.13.6) does not define __BYTE_ORDER__ and its C-library does
> not define __BYTE_ORDER. The compiler is supported only an arm64 and x86
> which are all little endian.

"an arm" -> "on arm"?  Just sanity checking before making local
typofix while queueing.

> Define GIT_BYTE_ORDER on msvc as little endian to avoid further checks.
>
> Signed-off-by: Sebastian Andrzej Siewior <[email-masked]>
> ---
>  compat/bswap.h | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/compat/bswap.h b/compat/bswap.h
> index 0a457542dd76a..fd604d9f7b74b 100644
> --- a/compat/bswap.h
> +++ b/compat/bswap.h
> @@ -81,6 +81,10 @@ static inline uint64_t git_bswap64(uint64_t x)
>  #define bswap32(x) _byteswap_ulong(x)
>  #define bswap64(x) _byteswap_uint64(x)
>  
> +#define GIT_LITTLE_ENDIAN 1234
> +#define GIT_BIG_ENDIAN 4321
> +#define GIT_BYTE_ORDER GIT_LITTLE_ENDIAN
> +
>  #endif
>  
>  #if defined(bswap32)
> @@ -122,7 +126,7 @@ static inline uint64_t git_bswap64(uint64_t x)
>  # define GIT_LITTLE_ENDIAN __ORDER_LITTLE_ENDIAN__
>  # define GIT_BIG_ENDIAN __ORDER_BIG_ENDIAN__
>  
> -#else
> +#elif !defined(GIT_BYTE_ORDER)
>  
>  # define GIT_BIG_ENDIAN 4321
>  # define GIT_LITTLE_ENDIAN 1234