Yes, alas, the short answer is NO.
The long answer is: Canon FD lenses *can* be used on Pentax dSLRs, but only with severe limitations or much delicate work. They're almost never worth the trouble.
___________________________________
As
jeztastic pointed out, the
flange-focal-distance aka
register is longer for Pentax than Canon FD. That means that, even if a Pentax mount were put on a C/FD lens, the lens would not be able to focus to infinity. So to be usable, an optical adapter is necessary. This acts as a short teleconverter -- the lens becomes longer, slower, and loses some IQ. If the lens was special before, it won't be afterwards.
A C/FD lens could be used for close or macro work, where infinity doesn't matter, but that's rather limiting, and there are mechanical interface problems; the aperture mechanism has a difficult design. That's why we don't see (m)any non-optical FD-PK adapters sold on eBay.
Another way to handle the register difference is to shorten the C/FD lens by about 3.5mm: chop-off the base of the lens. Unfortunately, most Canon lenses have rather important mechanisms and optics down there. Some third-party FD-mount lenses *could* be chopped, but only by someone with machine-shop tools and skills. I've modified other types of lenses; I won't go near FDs.
The other possible way is to reverse the lens and use it only for macro work. There are still problems with working the aperture. (Many folks consider the C/FD mount as among the worst ever designed.) Rather than reverse and/or adapt Canon lenses, I just sold what I had.
___________________________________
So, there are many good reasons for switching to Pentax, but C/FD compatibility ain't one of them.