Upon success, @code{@var{attr}->size} contains the size of the structure
version used by the kernel. Fields with offsets greater or equal to
-@code{@var{attr}->size} are not updated by the kernel. To obtain
-predictable values for unknown fields, use @code{memset} to set
-all @var{size} bytes to zero prior to calling @code{sched_getattr}.
+@code{@var{attr}->size} may not be overwritten by the kernel. To obtain
+predictable values for unknown fields, use @code{memset} to set all
+@var{size} bytes to zero prior to calling @code{sched_getattr}.
On failure, @code{sched_getattr} returns @math{-1} and sets @code{errno}.
If @code{errno} is @code{E2BIG}, this means that the buffer is not large
unsigned char padding[4096];
} u;
-static void
-check_unused (void)
-{
- TEST_VERIFY (u.attr.size < sizeof (u));
- for (unsigned int i = u.attr.size; i < sizeof (u); ++i)
- TEST_COMPARE (u.padding[i], 0xcc);
-}
-
static int
do_test (void)
{
/* Compiler barrier to bypass write access attribute. */
volatile unsigned int size = sizeof (u);
TEST_COMPARE (sched_getattr (0, (struct sched_attr *) &u, size, 0), 0);
- check_unused ();
TEST_COMPARE (sched_setattr (0, &u.attr, 0), 0); /* Apply unchanged. */
/* Try to switch to the SCHED_OTHER policy. */
memset (&u, 0xcc, sizeof (u));
TEST_COMPARE (sched_getattr (0, (struct sched_attr *) &u, size, 0), 0);
TEST_COMPARE (u.attr.sched_policy, SCHED_OTHER);
- check_unused ();
/* Raise the niceless level to 19 and observe its effect. */
TEST_COMPARE (nice (19), 19);
TEST_COMPARE (sched_getattr (0, &u.attr, sizeof (u.attr), 0), 0);
TEST_COMPARE (u.attr.sched_policy, SCHED_OTHER);
TEST_COMPARE (u.attr.sched_nice, 19);
- check_unused ();
/* Invalid buffer arguments result in EINVAL (not EFAULT). */
{