Hi, With the following code I get an Access Violation: unsigned char pattern[2] = { 2, 2}; GrLineOption linestyle = { 15, 1, 2, pattern }; GrCustomLine(-2, 0, 1, 0, &linestyle); I've followed the execution until the call to 'dashedsegment', but then I get a bit lost. What is clear is that when this function calls (*doseg), the variables 'start' and 'end' haven´t been initialized. Any help would be very wellcomed Thanks Josu Onandia jonandia@fagorautomation.es