How Do we access a file from local drive in hololens

gbhatt

Hello,
I have a C++ holographic app and in the code I want to read a file from my local file system and extract some data from it. I am not able to use fopen()/_aceess() etc functions successfully. Is there a way I can use open() on my file?
My program is an OpenGL program and I am using Angle to convert openGl to DirectX.
In universal windows app I found out that we have to use FilePicker object and StorageClass etc in order to access the file but all examples are with xaml and my program is just c++ project and I don't want to use xaml too.
Any suggestions?

Thanks a lot.

Dwight_Goins_EE_MVP

Hi gbhatt,

I have a simple example here: In the Recording Audio Demo. It's based on the UWP samples modified for Holographic api. It records sound from the HL microphone, and save it to an Audio .wav file in one of the Known folders

Here's a quick snippet of code:

        KnownFolders::CameraRoll->CreateFileAsync( AUDIO_FILE_NAME, CreationCollisionOption::GenerateUniqueName )).then(        
                [this]( StorageFile^ file )        
            {        
                if (nullptr == file)        
                {        
                    ThrowIfFailed( E_INVALIDARG );        
                }

                return file->OpenAsync( FileAccessMode::ReadWrite );        
            })

Note: you case use the
KnownFolders::CameraRoll->OpenFileAsync(...)

To Open a file asynchronously. Also keep in mind you have to make sure you give access in your package.manifest file as well.

gbhatt

Actually I am using Hololens Emulator to run my program. My understanding is that if I want to access any file in hololens It should be in OneDrive( can I do fopen() in a file stored in onedrive? ). But how to test that with the emulator. Is there a location from where I can access the file using emulator? I tried keeping file in /Appdata/local/ but fopen() returns null.

Dwight_Goins_EE_MVP

Hi gbhatt,

I have a simple example here: In the Recording Audio Demo. It's based on the UWP samples modified for Holographic api. It records sound from the HL microphone, and save it to an Audio .wav file in one of the Known folders

Here's a quick snippet of code:

        KnownFolders::CameraRoll->CreateFileAsync( AUDIO_FILE_NAME, CreationCollisionOption::GenerateUniqueName )).then(        
                [this]( StorageFile^ file )        
            {        
                if (nullptr == file)        
                {        
                    ThrowIfFailed( E_INVALIDARG );        
                }

                return file->OpenAsync( FileAccessMode::ReadWrite );        
            })

Note: you case use the
KnownFolders::CameraRoll->OpenFileAsync(...)

To Open a file asynchronously. Also keep in mind you have to make sure you give access in your package.manifest file as well.