Re: [Qemu-devel] [PATCH v2] HACKING: document #include order

[Markus Armbruster]

Stefan Hajnoczi <address@hidden> writes:

> It was not obvious to me why "qemu/osdep.h" must be the first #include.
> This documents the rationale and the overall #include order.
>
> Cc: Fam Zheng <address@hidden>
> Cc: Markus Armbruster <address@hidden>
> Cc: Eric Blake <address@hidden>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
>  HACKING | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/HACKING b/HACKING
> index 20a9101..4125c97 100644
> --- a/HACKING
> +++ b/HACKING
> @@ -1,10 +1,28 @@
>  1. Preprocessor
>  
> +1.1. Variadic macros
> +
>  For variadic macros, stick with this C99-like syntax:
>  
>  #define DPRINTF(fmt, ...)                                       \
>      do { printf("IRQ: " fmt, ## __VA_ARGS__); } while (0)
>  
> +1.2. Include directives
> +
> +Order include directives as follows:
> +
> +#include "qemu/osdep.h"  /* Always first... */
> +#include <...>           /* then system headers... */
> +#include "..."           /* and finally QEMU headers. */
> +
> +The "qemu/osdep.h" header contains preprocessor macros that affect the 
> behavior
> +of core system headers like <stdint.h>.  It must be the first include so that
> +core system headers included by external libraries get the preprocessor 
> macros
> +that QEMU depends on.
> +
> +Do not include "qemu/osdep.h" from header files since the .c file will have
> +already included it.
> +
>  2. C types
>  
>  It should be common sense to use the right type, but we have collected

Reviewed-by: Markus Armbruster <address@hidden>