Function SQLGetEnvAttr 

pub unsafe extern "system" fn SQLGetEnvAttr(
    environment_handle: HEnv,
    attribute: EnvironmentAttribute,
    value_ptr: Pointer,
    buffer_length: i32,
    string_length: *mut i32,
) -> SqlReturn

Gets attributes that govern aspects of environments

Returns

SUCCESS, SUCCESS_WITH_INFO, ERROR, or INVALID_HANDLE