Open File

Opens an existing file for reading or writing. You cannot use this function to create or replace files.

datalog type can be any data type. Wire a cluster matching the record data type and cluster order to this input when opening datalog files. If you wire it, LabVIEW assumes the specified file is a datalog file whose records are of the specified data type, in which case refnum is a datalog file refnum. In this case, the function returns an error if the format of the file does not match the format for a datalog file whose records are of the specified data type. The default is to assume the specified file is a byte stream file, in which case refnum is a byte stream file refnum.
file path is the full path of the file you want to open.
open mode specifies whether this function opens the file for both reading and writing data, for reading only, or for writing only.

0May both read and write to file (default).
1May only read from file.
2May only write to file. Does not truncate (remove all data from) the file. Under any non-Macintosh platform, this mode acts like mode 0.
3May only write to file. Truncates the file.
deny mode specifies the degree to which other users can operate on the file simultaneously.

0Deny both read and write to the file by other users.
1Permit read but deny write to the file by other users.
2Permit both read and write to the file by other users (default).
error in describes error conditions that occur before this VI or function runs. The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurs before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code. Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
status is TRUE (X) if an error occurred before this VI or function ran or FALSE (checkmark) to indicate a warning or that no error occurred before this VI or function ran. The default is FALSE.
code is the error or warning code. The default is 0. If status is TRUE, code is a non-zero error code. If status is FALSE, code is 0 or a warning code.
source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning. The default is an empty string.
refnum is the file refnum associated with the opened file. If file path does not refer to an existing file, or if it refers to an existing file that you cannot open with the specified open mode and deny mode, this function sets refnum to Not A Refnum.
error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces. Right-click the error out indicator on the front panel and select Explain Error from the shortcut menu for more information about the error.
status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.
code is the error or warning code. If status is TRUE, code is a non-zero error code. If status is FALSE, code is 0 or a warning code.
source describes the origin of the error or warning and is, in most cases, the name of the VI or function that produced the error or warning.