template <std::size_t num_devices>
void RegisterParallelDevice(
    TFE_Context* context, const char* device_name,
    const std::array<const char*, num_devices>& underlying_devices,
    TF_Status* status);

// Create and modify a variable placed on a parallel device which composes
// `first_device` and `second_device`.
void BasicTestsForTwoDevices(TFE_Context* context, const char* first_device,
                             const char* second_device);

// --------------------------------------------------------------------------
// The deprecated session API.  Please switch to the above instead of
// TF_ExtendGraph(). This deprecated API can be removed at any time without
// notice.

typedef struct TF_DeprecatedSession TF_DeprecatedSession;

TF_CAPI_EXPORT extern TF_DeprecatedSession* TF_NewDeprecatedSession(
    const TF_SessionOptions*, TF_Status* status);

#define TENSORFLOW_C_EAGER_C_API_H_

// C API extensions to experiment with eager execution of kernels.
// WARNING: Unlike tensorflow/c/c_api.h, the API here is not guaranteed to be
// stable and can change without notice.

#include "tensorflow/c/c_api.h"
#include "tensorflow/c/c_api_macros.h"

#ifdef __cplusplus
extern "C" {
#endif

typedef struct TFE_ContextOptions TFE_ContextOptions;

// Return a new options object.

    }
    TF_VLog(1, "GCS file block cache is %s.\n",
            (IsCacheEnabled() ? "enabled" : "disabled"));
  }

  ~RamFileBlockCache() {
    if (pruning_thread_) {
      stop_pruning_thread_.Notify();
      // Destroying pruning_thread_ will block until Prune() receives the above
      // notification and returns.
      pruning_thread_.reset();
    }
  }

// through custom device implementations).
//
// TODO(allenl): Currently these are black boxes, but we should have some way to
// inspect values. This would let people e.g. copy over most attributes and then
// modify some based on their values.

// A reference to an op's name -> attribute mapping
typedef struct TFE_OpAttrs TFE_OpAttrs;

// Fetch a reference to `op`'s attributes. The returned reference is only valid

/// `cleanup` functions (one for each data structure), the `init` function for
/// `TF_Filesystem` and the `new_*` methods of `TF_FilesystemOps` to initialize
/// the 3 types of files. In all other cases, there is no need to modify the
/// address of the opaque data pointer, hence the wrapper pointer is marked
/// `const`.
///
/// For consistency, the arguments on all these functions follow the same