hmemcpy is a krnl386 function, that is, a function that resides in the 16 bit portion of the windows (9x) kernel. you don't have it under nt or 2k since the underlying system architecture is made up of pure 32 bit code in such OS's. as for what function does the same, i've heard alot of rambling about memcpy (or was it memcopy?) having a roughly similar role, but i couldnt tell. i havent been cracking for ages, and i've done even less cracking under nt, so i'm not really the one who'll answer this question. the functons that will not work are simply the ones exported by 16 bit modules (kernel, user, gdi, etc) in the 9x core. the 'common' winapi functions will be alright to break on. a good chance if you approach cracking under nt/2k is given by taken into account ntoskrnl and every other module peculiar to those systems. as a rule of thumb, what's not pointed out as being "obsolete" in your win32 api reference, is likely to be a possible breakpoint, independently from the platform.

hope that helps a bit,