I've got a line of code that calls a function, specifying some arguments and a keyword. This line works in IDL 5.4 for Windows, but gives a syntax error in IDL 6.0 for Linux. Strangely, it generally seems to happen when the number of non-optional arguments is higher. For instance: foo(a, MY_KEYWORD=my_keyword) bar(a, b, c, d, MY_KEYWORD=my_keyword) This code works perfectly in IDL 5.4 for Windows. However, in IDL 6.0 for Linux, the second line gives a syntax error while the first line goes through without issue. I believe the problem is related to the keyword specification because removing it makes the syntax error go away immediately. Thank you in advance for any insight anyone can provide. -Ben