Write Event

Fires when the OS needs to write data to an open file.

Syntax

• C#
• VB.NET

public event OnWriteHandler OnWrite;

public delegate void OnWriteHandler(object sender, FuseWriteEventArgs e);

public class FuseWriteEventArgs : EventArgs {
  public string Path { get; }
  public int FileContext { get; }
  public bool WritePage { get; }
  public long Offset { get; }
  public IntPtr Buffer { get; }
  public long Size { get; }
  public int Result { get; set; }
}

Public Event OnWrite As OnWriteHandler

Public Delegate Sub OnWriteHandler(sender As Object, e As FuseWriteEventArgs)

Public Class FuseWriteEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As Integer
  Public ReadOnly Property WritePage As Boolean
  Public ReadOnly Property Offset As Long
  Public ReadOnly Property Buffer As IntPtr
  Public ReadOnly Property Size As Long
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs to write data to the already-open file, identified by either Path or FileContext.

To handle this event properly, applications should write Size bytes of data from the memory region pointed to by Buffer to the specified file. Writing must begin at the specified Offset in the file and all of the provided data is expected to be written.

Please refer to the Buffer Parameters topic for more information on how to work with memory buffer event parameters.

The WritePage parameter will be set to a non-zero value when writing is performed by the cache manager or another system component. If this is the case, FileContext may not match the value that would be passed in the case of a non-buffered write by a user-mode process.

When writing is complete, applications must set Result to the actual number of bytes written to the file.

If the event cannot be handled in a "successful" manner for some reason (e.g., a resource isn't available, security checks failed, etc.), set it to a negative error code value (e.g. -ENOENT to indicate that the file does not exist) to report an appropriate error. Please refer to the Error Reporting and Handling topic for more information.