@acer I'm using Maple 18 on OSX 10.10.4. I'm not very familiar with the GUI, but I believe I'm using a Worksheet.
As the function goes through its steps, it has short printf statements to print current progress. Each printf is a single line of text. In the command line interface, it works fine, and whenever the printf statement is reached the output appears in the terminal. In the GUI, (as Carl Love stated) the output doesn't appear either execution is finished (or sometimes, a block of 100 or so lines will appear all at once in the middle of execution). What I would like is for each line to appear as each printf is called.
I don't want to use a component because I'd like the same version to work in both CLI and GUI interfaces. I can't come up with a simple example that exhibits this issue, but I've experienced this issue with completely unrelated programs, so it's not specific to this implementation.