ListRemoveDuplicates

[altronics]

I create a List using:

static ListType List_Session = 0;

List_Session = ListCreate (sizeof(char[20]));

Then I load this list with strings named as such:

SESSION T1

SESSION T3

SESSION Q1

SESSION Q1

Some of the names are duplicated which I am trying to use ListRemoveDuplicates (List_Session , 0); to remove them, but it is not working.  I am not sure, but I think the issue is with the compare fucntion that is being used.  0 just uses the memcmp() by default and I believe I need to pass CStringCompare() or similar funtion in its place, but I cannot figure out how and I cannot find an example of using ListRemoveDuplicates and CStringCompare. 

Any help on how to format and pass the correct arguements would be appreciated.

[Caseyw]

Hello,

I would be glad to help you with this issue. You can write a simple comparison function to use within the ListRemoveDuplicates function that uses strncmp. I have included an example below:

int CVICALLBACK MyCompareFunction(void * item1,void * item2)
{
 
  int MyInt;
  MyInt = strncmp(item1,item2,100);
  return MyInt;

}

This should work great. As a side note, you will want to make sure that your character arrays contain enough characters to represent a NUL at the end of each string.

I hope this helps!

Casey Weltzin

Applications Engineer

National Instruments

[altronics]

Would I then call this fuction as such:  ListRemoveDuplicates (List_Session , MyCompareFunction(item1,item2));  and  how would I initialize item1 and item2?  Would one call to ListRemoveDuplicates go thru the entire list or would I need to increment item1 and item2 and call repeatedly?

[Caseyw]

Hello,

Your call to the ListRemoveDuplicates function should resemble the following:

ListRemoveDuplicates(MyList,strncmp);

The ListRemoveDuplicates function will automatically call your comparison function (in this case strncmp) for each combination of list items, so you only need to call it once. I hope this answers your questions, please let me know if you need any more help. Have a great morning!

Regards,

Casey Weltzin

Applications Engineer

National Instruments