NvAPI Status Values All NvAPI functions return one of these codes.

Enumerator:

NVAPI_OK	Success. Request is completed.
NVAPI_ERROR	Generic error.
NVAPI_LIBRARY_NOT_FOUND	NVAPI support library cannot be loaded.
NVAPI_NO_IMPLEMENTATION	not implemented in current driver installation
NVAPI_API_NOT_INTIALIZED	NvAPI_Initialize has not been called (successfully).
NVAPI_INVALID_ARGUMENT	The argument/parameter value is not valid or NULL.
NVAPI_NVIDIA_DEVICE_NOT_FOUND	No NVIDIA display driver, or NVIDIA GPU driving a display, was found.
NVAPI_END_ENUMERATION	No more items to enumerate.
NVAPI_INVALID_HANDLE	Invalid handle.
NVAPI_INCOMPATIBLE_STRUCT_VERSION	An argument's structure version is not supported.
NVAPI_HANDLE_INVALIDATED	The handle is no longer valid (likely due to GPU or display re-configuration).
NVAPI_OPENGL_CONTEXT_NOT_CURRENT	No NVIDIA OpenGL context is current (but needs to be).
NVAPI_NO_GL_EXPERT	OpenGL Expert is not supported by the current drivers.
NVAPI_INSTRUMENTATION_DISABLED	OpenGL Expert is supported, but driver instrumentation is currently disabled.
NVAPI_EXPECTED_LOGICAL_GPU_HANDLE	Expected a logical GPU handle for one or more parameters.
NVAPI_EXPECTED_PHYSICAL_GPU_HANDLE	Expected a physical GPU handle for one or more parameters.
NVAPI_EXPECTED_DISPLAY_HANDLE	Expected an NV display handle for one or more parameters.
NVAPI_INVALID_COMBINATION	The combination of parameters is not valid.
NVAPI_NOT_SUPPORTED	Requested feature is not supported in the selected GPU.
NVAPI_PORTID_NOT_FOUND	No port ID was found for the I2C transaction.
NVAPI_EXPECTED_UNATTACHED_DISPLAY_HANDLE	Expected an unattached display handle as one of the input parameters.
NVAPI_INVALID_PERF_LEVEL	Invalid perf level.
NVAPI_DEVICE_BUSY	Device is busy; request not fulfilled.
NVAPI_NV_PERSIST_FILE_NOT_FOUND	NV persist file is not found.
NVAPI_PERSIST_DATA_NOT_FOUND	NV persist data is not found.
NVAPI_EXPECTED_TV_DISPLAY	Expected a TV output display.
NVAPI_EXPECTED_TV_DISPLAY_ON_DCONNECTOR	Expected a TV output on the D Connector - HDTV_EIAJ4120.
NVAPI_NO_ACTIVE_SLI_TOPOLOGY	SLI is not active on this device.
NVAPI_SLI_RENDERING_MODE_NOTALLOWED	Setup of SLI rendering mode is not possible right now.
NVAPI_EXPECTED_DIGITAL_FLAT_PANEL	Expected a digital flat panel.
NVAPI_ARGUMENT_EXCEED_MAX_SIZE	Argument exceeds the expected size.
NVAPI_DEVICE_SWITCHING_NOT_ALLOWED	Inhibit is ON due to one of the flags in NV_GPU_DISPLAY_CHANGE_INHIBIT or SLI active.
NVAPI_TESTING_CLOCKS_NOT_SUPPORTED	Testing of clocks is not supported.
NVAPI_UNKNOWN_UNDERSCAN_CONFIG	The specified underscan config is from an unknown source (e.g. INF).
NVAPI_TIMEOUT_RECONFIGURING_GPU_TOPO	Timeout while reconfiguring GPUs.
NVAPI_DATA_NOT_FOUND	Requested data was not found.
NVAPI_EXPECTED_ANALOG_DISPLAY	Expected an analog display.
NVAPI_NO_VIDLINK	No SLI video bridge is present.
NVAPI_REQUIRES_REBOOT	NVAPI requires a reboot for the settings to take effect.
NVAPI_INVALID_HYBRID_MODE	The function is not supported with the current Hybrid mode.
NVAPI_MIXED_TARGET_TYPES	The target types are not all the same.
NVAPI_SYSWOW64_NOT_SUPPORTED	The function is not supported from 32-bit on a 64-bit system.
NVAPI_IMPLICIT_SET_GPU_TOPOLOGY_CHANGE_NOT_ALLOWED	There is no implicit GPU topology active. Use NVAPI_SetHybridMode to change topology.
NVAPI_REQUEST_USER_TO_CLOSE_NON_MIGRATABLE_APPS	Prompt the user to close all non-migratable applications.
NVAPI_OUT_OF_MEMORY	Could not allocate sufficient memory to complete the call.
NVAPI_WAS_STILL_DRAWING	The previous operation that is transferring information to or from this surface is incomplete.
NVAPI_FILE_NOT_FOUND	The file was not found.
NVAPI_TOO_MANY_UNIQUE_STATE_OBJECTS	There are too many unique instances of a particular type of state object.
NVAPI_INVALID_CALL	The method call is invalid. For example, a method's parameter may not be a valid pointer.
NVAPI_D3D10_1_LIBRARY_NOT_FOUND	d3d10_1.dll cannot be loaded.
NVAPI_FUNCTION_NOT_FOUND	Couldn't find the function in the loaded DLL.