From: Thierry Reding <[email protected]>
The code previously tried to compute the offset of a field in the
valuator by subtracting the address of the valuator from the _value_ of
the field (rather than the field's address). The correct way to do it
would have been (note the &'s):
assert(((void *) &v->axisVal - (void *) v) % sizeof(double) == 0);
assert(((void *) &v->axes - (void *) v) % sizeof(double) == 0);
That's essentially what the offsetof() macro does. Using offsetof() has
the added benefit of not using void pointer arithmetic and therefore
silencing a warning on some compilers.
Signed-off-by: Thierry Reding <[email protected]>
---
test/input.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/test/input.c b/test/input.c
index 5813e6dc987b..9b5db89919f5 100644
--- a/test/input.c
+++ b/test/input.c
@@ -1390,8 +1390,8 @@ dix_valuator_alloc(void)
assert(v->numAxes == num_axes);
#if !defined(__i386__) && !defined(__m68k__) && !defined(__sh__)
/* must be double-aligned on 64 bit */
- assert(((void *) v->axisVal - (void *) v) % sizeof(double) == 0);
- assert(((void *) v->axes - (void *) v) % sizeof(double) == 0);
+ assert(offsetof(struct _ValuatorClassRec, axisVal) % sizeof(double) ==
0);
+ assert(offsetof(struct _ValuatorClassRec, axes) % sizeof(double) == 0);
#endif
num_axes++;
}
--
1.8.4.2
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