C++ (Cpp) _Atomic_Compare_exchange_uint Examples

Example #1

File: close.c Project: gedare/rtems

int close(
  int  fd
)
{
  rtems_libio_t *iop;
  unsigned int   flags;
  int            rc;

  if ( (uint32_t) fd >= rtems_libio_number_iops ) {
    rtems_set_errno_and_return_minus_one( EBADF );
  }

  iop = rtems_libio_iop( fd );
  flags = rtems_libio_iop_flags( iop );

  while ( true ) {
    unsigned int desired;
    bool         success;

    if ( ( flags & LIBIO_FLAGS_OPEN ) == 0 ) {
      rtems_set_errno_and_return_minus_one( EBADF );
    }

    /* The expected flags */
    flags &= LIBIO_FLAGS_REFERENCE_INC - 1U;

    desired = flags & ~LIBIO_FLAGS_OPEN;
    success = _Atomic_Compare_exchange_uint(
      &iop->flags,
      &flags,
      desired,
      ATOMIC_ORDER_ACQ_REL,
      ATOMIC_ORDER_RELAXED
    );

    if ( success ) {
      break;
    }

    if ( ( flags & ~( LIBIO_FLAGS_REFERENCE_INC - 1U ) ) != 0 ) {
      rtems_set_errno_and_return_minus_one( EBUSY );
    }
  }

  rc = (*iop->pathinfo.handlers->close_h)( iop );

  rtems_libio_free( iop );

  return rc;
}

Example #2

File: init.c Project: Avanznow/rtems

static void test_simple_atomic_compare_exchange_body(test_context *ctx)
{
  unsigned int ei;
  unsigned int vi;
  uintptr_t ep;
  uintptr_t vp;
  unsigned long el;
  unsigned long vl;
  bool success;

  puts("=== atomic simple compare exchange test case ===");

  _Atomic_Store_uint(&ctx->uint_atomic, 1, ATOMIC_ORDER_RELAXED);
  ei = 2;
  success = _Atomic_Compare_exchange_uint(
    &ctx->uint_atomic,
    &ei,
    3,
    ATOMIC_ORDER_RELAXED,
    ATOMIC_ORDER_RELAXED
  );
  rtems_test_assert(!success);
  rtems_test_assert(ei == 1);
  success = _Atomic_Compare_exchange_uint(
    &ctx->uint_atomic,
    &ei,
    3,
    ATOMIC_ORDER_RELAXED,
    ATOMIC_ORDER_RELAXED
  );
  rtems_test_assert(success);
  vi = _Atomic_Load_uint(&ctx->uint_atomic, ATOMIC_ORDER_RELAXED);
  rtems_test_assert(vi == 3);

  _Atomic_Store_uintptr(&ctx->uintptr_atomic, 111, ATOMIC_ORDER_RELAXED);
  ep = 211;
  success = _Atomic_Compare_exchange_uintptr(
    &ctx->uintptr_atomic,
    &ep,
    311,
    ATOMIC_ORDER_RELAXED,
    ATOMIC_ORDER_RELAXED
  );
  rtems_test_assert(!success);
  rtems_test_assert(ep == 111);
  success = _Atomic_Compare_exchange_uintptr(
    &ctx->uintptr_atomic,
    &ep,
    311,
    ATOMIC_ORDER_RELAXED,
    ATOMIC_ORDER_RELAXED
  );
  rtems_test_assert(success);
  vp = _Atomic_Load_uintptr(&ctx->uintptr_atomic, ATOMIC_ORDER_RELAXED);
  rtems_test_assert(vp == 311);

  _Atomic_Store_ulong(&ctx->ulong_atomic, 10, ATOMIC_ORDER_RELAXED);
  el = 11;
  success = _Atomic_Compare_exchange_ulong(
    &ctx->ulong_atomic,
    &el,
    12,
    ATOMIC_ORDER_RELAXED,
    ATOMIC_ORDER_RELAXED
  );
  rtems_test_assert(!success);
  rtems_test_assert(el == 10);
  success = _Atomic_Compare_exchange_ulong(
    &ctx->ulong_atomic,
    &el,
    12,
    ATOMIC_ORDER_RELAXED,
    ATOMIC_ORDER_RELAXED
  );
  rtems_test_assert(success);
  vl = _Atomic_Load_ulong(&ctx->ulong_atomic, ATOMIC_ORDER_RELAXED);
  rtems_test_assert(vl == 12);
}