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Re: type behavior of sys/endian.h
On Jul 25, 2009, at 9:41 PM, David Holland wrote:
On Wed, Jul 22, 2009 at 01:12:42AM +0200, Joerg Sonnenberger wrote:
Or maybe they should be made inline functions instead so they don't
fail silently if passed pointers.
So we have two approach:
(1) Cast the value directly.
(2) Use inline functions.
When doing (2), fxp(4) doesn't compile as the follow construct
a gcc warning:
with mask being some signed small constant. This even happens if
unsigned or already of the correct width.
le16toh(~1) -> nothing
le16toh(~1U) -> "large integer implicitly truncated to unsigned
le16toh(~32767) -> nothing
le16toh(~32767U) -> "large integer implicitly truncated to unsigned
le16toh(~32769) -> "large integer implicitly truncated to unsigned
le16toh(~32769U) -> "large integer implicitly truncated to unsigned
This makes no sense, and I think gcc must be doing something wrong
internally, more than just printing a not-quite-relevant message. But
everything involving shorts is aggravating, so maybe not.
This make perfect sense to me. The two values without a warning
convert from int to short with no loss of representation. All the
other have value outside -32768..32767 and thus must be truncated to
The warning happens when N != (short) N or N != (unsigned short) N
depending on whether N is unsigned.
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