Class

IOException

Description

Raised when an IO error occurs in classes that perform file or stream operations, including BinaryStream, FolderItem, PDFDocument, SerialConnection, SpecialFolder, TextInputStream, and TextOutputStream.

Properties

Name	Type	Read-Only	Shared
ErrorNumber	Integer
Message	String

Methods

Name	Parameters	Returns
Constructor	message As String = "", errorNumber As Integer = 0
Stack		String()
StackFrames		StackFrame()

Property descriptions

IOException.ErrorNumber

ErrorNumber As Integer

Used to contain an error number that describes the runtime error.

IOException.Message

Message As String

Used to contain descriptive text to display when the runtime exception is encountered.

Method descriptions

IOException.Constructor

Constructor(message As String = "", errorNumber As Integer = 0)

Note

Constructors are special methods called when you create an object with the New keyword and pass in the parameters above.

Used to raise your own RuntimeException with a message and optional error number.

IOException.Stack

Stack As String()

Returns a String array that contains a list of all of the methods in the stack from the main entrypoint to the point at which the exception was invoked.

The stack contains all the method names up and including the current method name.

This feature only works if the IncludeFunctionNames property on the App object is selected in the Shared Build Settings.

In addition to your own method calls, you will also see framework method calls, but these may not always be completely accurate due to insufficient symbols for the OS to resolve.

IOException.StackFrames

StackFrames As StackFrame()

Returns an array containing the stack when the exception was first raised.

Notes

An IOException can be raised by any class that performs file or stream operations. This includes BinaryStream, FolderItem, PDFDocument, SerialConnection, SpecialFolder, TextInputStream, and TextOutputStream. Always wrap IO operations in a Try/Catch block to handle these errors gracefully.

Error codes

The ErrorNumber property of an IOException may be set to an OS error code.

macOS

The OS Status web site can help track down error code meanings.

In addition, you can use the macerror command in Terminal to find a description of an error.

For example:

macerror -49 displays: Mac OS error -49 (opWrErr): file already open with write permission

Windows

Windows error codes are available at MSDN.

Linux

Error Codes for Linux can be found here.

Sample code

The following example catches an IOException if it occurs.

Var f As FolderItem = FolderItem.ShowSaveFileDialog(FileTypes1.Text, "Create Example.txt")

If f <> Nil Then
  Var t As TextOutputStream = TextOutputStream.Create(f)  ' this line could raise an IOException.
  t.WriteLine(TextField1.Text)
  t.Close
End If

Exception err As IOException
  MessageBox("An error occurred while attempting to create/save the file.")

Compatibility

Project Types	All
Operating Systems	All