[Ffmpeg-devel] gcc4 support & MMX fixups (from Debian)

Pawel Sikora pluto
Thu Feb 2 10:36:02 CET 2006

On Thu, 2 Feb 2006, Michael Niedermayer wrote:

> Hi
> On Thu, Feb 02, 2006 at 09:41:37AM +0100, Pawe? Sikora wrote:
>>>> I suggest we should use a size_t type for params like *_stride
>>>> to avoid (on x86-64) unneeded 32<->64 conversions.
>>> no, size_t is unsigned, stride must be signed!
>> Right, I think off_t from sys/types.h is a good candidate.
>> It's signed, on x86-32 has 32 bits, on x86-64 has 64 bits.
> NO!
> -- Data Type: off_t
>     This is an arithmetic data type used to represent file sizes.  In
>     the GNU system, this is equivalent to `fpos_t' or `long int'.
>     If the source is compiled with `_FILE_OFFSET_BITS == 64' this type
>     is transparently replaced by `off64_t'.

Ok, last attempt  - ptrdiff_t.

C and C++ define a special type for pointer arithmetic, namely ptrdiff_t,
which is a typedef of a platform-specific signed integral type. You can
use a variable of type ptrdiff_t to store the result of subtracting and
adding pointers.

to_be || !to_be == 1, to_be | ~to_be == -1

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