Re: [PATCH 03/22] tools lib traceevent: Add traceevent_host_bigendian function

[Namhyung Kim <namhyung@kernel.org>]

Hi Steve,

On Sat, 23 Nov 2013 03:27:08 -0500, Steven Rostedt wrote:
> On Fri, 22 Nov 2013 23:22:52 +0900
> Namhyung Kim <namhyung@kernel.org> wrote:
>
>> 2013-11-21 (목), 12:01 +0100, Jiri Olsa:
>> > Adding traceevent_host_bigendian function to get host
>> > endianity. It's used in following patches.
>> 
>> [SNIP]
>> > +static inline int traceevent_host_bigendian(void)
>> > +{
>> > +	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4 };
>> > +	unsigned int *ptr;
>> > +
>> > +	ptr = (unsigned int *)str;
>> > +	return *ptr == 0x01020304;
>> 
>> Is it safe for every architecture supported - especially ones that
>> require stricter alignment?  I know many architectures/compilers align
>> stack but not sure doing this is safe for all architecture.
>
> Would you prefer this (I tested it on both a big and little endian)
>
> {
> 	unsigned char str[] = { 0x1, 0x2, 0x3, 0x4 };
> 	unsigned int val;
>
> 	memcpy(&val, str, 4);
> 	return val == 0x01020304;
> }

Yeah, looks good to me.

Thanks,
Namhyung