Open/Create/Replace File (G Dataflow)

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Last Modified: February 28, 2020

Obtains a reference to a file.

Programming Patterns

Opening, Processing, and Closing Files

Inputs/Outputs
Compatibility

prompt

Custom message in the title bar of the file dialog box that appears when you do not wire a value to the input path.

file path

Absolute path to the file you want to open. If you do not wire a value to path, this node displays a dialog box from which you can select a file or folder. If you specify an empty or relative path, this node returns an error

operation

Action that this node is allowed to perform on the specified file.

Name	Description
open	Opens an existing file.
replace	Replaces an existing file by opening the file and setting its end of file to 0.
create	Creates a new file.
open or create	Opens an existing file or creates a new file if one does not exist.
replace or create	Creates a new file or replaces a file if it exists. This node replaces a file by opening the file and setting its end of file to 0.
replace or create with confirmation	Creates a new file or replaces a file if it exists and you give permission. This node replaces a file by opening the file and setting its end of file to 0.

Default: open

access

Allowable ways to access the returned file.

Name	Description
read/write	Allows you to read or write to the returned file.
read-only	Allows you to read from the returned file.
write-only	Allows you to write to the returned file.

Default: read/write

error in

Error conditions that occur before this node runs.

The node responds to this input according to standard error behavior.

Standard Error Behavior

Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

error in does not contain an error	error in contains an error

If no error occurred before the node runs, the node begins execution normally. If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.	If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Default: No error

disable buffering

A Boolean that specifies whether the file opens without buffering, which, for large amounts of data, may increase the rate of data transfer to the file.

True	The file opens without buffering.
False	The file opens with buffering.

Default: False

refnum out

Reference to the open file.

If the file cannot be opened, the value of this output is Not A Refnum.

cancelled?

A Boolean value that indicates whether the user cancelled the dialog box that appears if no input file was wired to this node.

True	The dialog box was cancelled.
False	The dialog box was not cancelled, or the dialog box did not appear.

error out

The node produces this output according to standard error behavior.

This node can return the following error codes.

7	The user attempted to open or replace a file that cannot be found.
10	The user attempted to create a file that already exists.
43	The user cancelled the dialog box.

Note

This is not a comprehensive list of errors this node can return.

Standard Error Behavior

error in does not contain an error	error in contains an error

If no error occurred before the node runs, the node begins execution normally. If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.	If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

Where This Node Can Run:

Desktop OS: Windows

FPGA: All devices (only within an optimized FPGA VI)

Web Server: Not supported in VIs that run in a web application

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