LabVIEW programming topics - Using arrays in ini files

Introduction

LabVIEW provides a convenient way to read single data elements from and to write single data elements to ini (config) files. However, for a series of similar data elements, e.g. an array, you should create some method of your own.

The presented method assumes you want to use the following type of data in your ini file:

[section]
key=value1, value2, value3, .., valuen

In other words all data elements of an array are stored as a single key.

These data elements may represent numerical values, booleans, or strings as in the following example:

[sample section]
boolean=TRUE,FALSE,TRUE,FALSE
double=1,2,3,4

Solution for reading the ini file

The general approach would be to read the entire entry behind key= as a string. Using the Spreadsheet String to Array function, with a comma as the delimiter, to convert this into an array of the desired type.

Solution for writing the ini file

The general approach would be to convert the data elements of an array to a spreadsheet string with the Array to Spreadsheet String function with a comma as the delimiter.

Implementation

This method requires a separate function for each data type. Fortunately LabVIEW offers a method to store all related funtions in a single library and a method to combine similar functions in a polymorphic function.

Sample program

The sample program shows how to read/write values from an array of doubles and an array of Booleans.

Downloads

ini file support - arrays.zip

which includes:

• ini - open file.vi
• ini - array.llb
• ini - read array.vi
• ini - write array.vi
• ini - test array.vi

Remarks

• The presented VIs were created with LabVIEW 8.5.1.
• The presented VIs works fine for Booleans, strings (without commas) and the following numerical values: double, single and both signed and unsigned integer.
• The function for the single format has been derived from the function for the double format. It can be used as an example for other derived formats.
• When you close an ini file that needs to be updated, don't forget to explicitely wire a TRUE constant to the Close Config Data function.
• There is no function for Path arrays.

Bart Boshuizen, 2011/02/28