// that provides the filesystem functionality. However, the POSIX filesystem
// needs to be statically registered in some tests and utilities for building
// the API files at the time of creating the pip package. Hence, we need to
// expose this function so that this filesystem can be statically registered
// when needed.
void TF_InitPlugin(TF_FilesystemPluginInfo* info);

// Returns the number of TF_Functions registered in `g`.
TF_CAPI_EXPORT extern int TF_GraphNumFunctions(TF_Graph* g);

// Fills in `funcs` with the TF_Function* registered in `g`.
// `funcs` must point to an array of TF_Function* of length at least
// `max_func`. In usual usage, max_func should be set to the result of
// TF_GraphNumFunctions(g). In this case, all the functions registered in

// devices, so executing tf.functions which contain operations placed on the
// custom devices will fail.
//
// `device_name` must not name an existing physical or custom device. It must
// follow the format:
//
//    /job:<name>/replica:<replica>/task:<task>/device:<type>:<device_num>
//
// If the device is successfully registered, `status` is set to TF_OK. Otherwise

  // Returns whether `device_name` is registered as a custom device.
  virtual bool IsCustomDevice(const string& device_name) = 0;

  // Register a custom device. It will return error is the device name is
  // already registered.
  // TODO(tfrt-devs): Remove this method. Let caller register it directly into
  // CustomDeviceOpHandler.

// call.
TF_AbstractFunction* TF_FinalizeFunction(TF_ExecutionContext* ctx,
                                         TF_OutputList*, TF_Status*);

void TF_DeleteAbstractFunction(TF_AbstractFunction*);

// Register the function with the given context. This is particularly useful for
// making a function available to an eager context.
void TF_ExecutionContextRegisterFunction(TF_ExecutionContext*,

// gradients.
//
// `ZerosLike` is not expected to be called and returns a nullptr. The creation
// of default zeros grads is handled by the `DefaultGradientFunction` registered
// for each op.
// TODO(srbs): We need to define `ZerosLike` here to keep the compiler happy.
// Figure out a way to avoid this.
// TODO(srbs): Should ZerosLike check-fail instead of returning nullptr?

  // adding inputs and finally executing (immediately or lazily as in tracing)
  // it in this context.
  virtual AbstractOperation* CreateOperation() = 0;

  // Registers a function with this context, after this the function is
  // available to be called/referenced by its name in this context.
  virtual Status RegisterFunction(AbstractFunction*) = 0;

                                                     const char* name,
                                                     TF_Status* status);

// Checks whether a function is registered under `name`.
TF_CAPI_EXPORT unsigned char TFE_ContextHasFunction(TFE_Context* ctx,
                                                    const char* name);

TF_CAPI_EXPORT extern void
TF_ImportGraphDefOptionsSetValidateColocationConstraints(
    TF_ImportGraphDefOptions* opts, unsigned char enable);

// Load the library specified by library_filename and register the pluggable
// device and related kernels present in that library. This function is not
// supported on embedded on mobile and embedded platforms and will fail if
// called.
//

  ///
  /// A filesystem is registered for a specific scheme and all of the methods
  /// should work with URIs. Hence, each filesystem needs to be able to
  /// translate from an URI to a path on the filesystem. For example, this
  /// function could translate `fs:///path/to/a/file` into `/path/to/a/file`, if
  /// implemented by a filesystem registered to handle the `fs://` scheme.
  ///