The term "all-purpose flour" is applied to two totally different types of flour depending on whether it is purchased in the U.S. or Canada. (forgive me, all those who hail from outside North America, I know nothing about your flour)*.

Canadian "all-purpose flour" will produce good results in a breadmaker, whereas American "all-purpose flour" will produce poor results. Americans must use bread flour in their breads, and cake flours in their cakes, because their "all-purpose flours" is not nearly as fine as Canadian flour.

Canada has a lot of wheat, and we create a lot of flour. Our all-purpose flour is exactly the same as our bread flours and our cake flours. We only give them these names as a marketing tactic. American bread flour is actually different from American all-purpose flour, because they don't have nearly as much nice flour to choose from, since Canada has sent them all of our crappy flour. Sorry.

*BlueDragon says: bread flour is called 'strong flour' in the UK, then there's 'flour' which is your all-purpose flour, and you can sometimes buy 'cake flour'.