Hi , It would be nice if you could add the explanation in the FAQ at the kernelnewbies.org website . More info here http://mail.nl.linux.org/kernelnewbies/2003-11/msg00014.html Cheers ! --- Jan Hudec <bulb@xxxxxx> wrote: > On Mon, Jan 03, 2005 at 10:46:49 -0800, Om wrote: > > Michael R. Hines wrote: > > > > > >The ones with underscores usually have matching > functions withOUT > > >underscores. They are meant to be private calls. > > > > > >The ones without underscores usually call the one > with underscores, and > > >these are the ones that actually do the work. > > > > > >The kernel will sometimes call the underscore'd > functions directly > > >because it knows what it's doing....... > > > > > >But while programming, we should generally call > the ones without them. > > Yes, unless we know what we do ;-) > > for example, lets take arch/i386/lib/usercopy.c : > copy_to_user(). This > > function performs some checks (access_ok()) on the > passed parameter and > > then call the actual function that implements the > functionlity > > include/asm/uaccess.h:__copy_to_user(). The > implementation might use > > other functions as well. > > > > If the target area is already checked for > access_ok, then the caller > > call skip the call copy_to_user() and make a call > directly to > > __copy_to_user(). This will save some time/code > size. > > > > I am not familiar with functions with single > underscore starting. But > > the idea is same. > > In fact I believe it's not. While __ means something > like "bare bones > version to use if you are sure you have made all > sanity-checks and hold > all the locks", _ rather means "this function isn't > here". Symbols > starting with one _ are traditionaly used for > library symbols, that > should have been static, but for some techical > reason can't. I believe > it's the same in kernel. > > ------------------------------------------------------------------------------- > Jan 'Bulb' Hudec <bulb@xxxxxx> > > ATTACHMENT part 2 application/pgp-signature name=signature.asc __________________________________ Do you Yahoo!? Yahoo! Mail - 250MB free storage. Do more. Manage less. http://info.mail.yahoo.com/mail_250 -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
