|
Date: Tue, 10 Oct 2017 16:56:54 -0400 From: Rich Felker <dalias@...c.org> To: musl@...ts.openwall.com Subject: Re: [PATCH] stdio: implement fopencookie(3) On Tue, Oct 10, 2017 at 08:51:17PM +0200, Jens Gustedt wrote: > Hello William, > > On Tue, 10 Oct 2017 18:03:56 +0000 William Pitcock > <nenolod@...eferenced.org> wrote: > > > The fopencookie(3) function allows the programmer to create a custom > > stdio implementation, using four hook functions which operate on a > > "cookie" data type. > > I know it is not your fault, but the naming conventions in this new > interface are realy bad design. > > > +typedef struct { > > + ssize_t (*read)(void *cookie, char *buf, size_t size); > > + ssize_t (*write)(void *cookie, const char *buf, size_t size); > > + int (*seek)(void *cookie, off_t *offset, int whence); > > + int (*close)(void *cookie); > > +} cookie_io_functions_t; > > > +FILE *fopencookie(void *cookie, const char *mode, cookie_io_functions_t io_funcs); > > The members may clash with macro names. E.g an implementation would be > allowed to overload "close" with a macro. This is not possible if the > implementation would want to use this interface here at the same time. > > User code could legitimately want to use a macro "seek" for its own > purpose. > > Could you at least avoid to use user-space names as function > parameters? Here you should just omit cookie, buf, size, offset, > whence, mode and io_funcs. I think in musl parameters in prototypes > usually don't have names. If you think that we should have them (they > sort of document the interface) you should put them into a reserved > namespace with leading underscore or so, or at least prefix them with > cookie_ I agree with most of the principles here (esp. how bad the public interface of this function is), but there's not a whole lot that can be done. Your one request is reasonable and in fact mandatory for musl header policy: we do not use parameter named at all in prototypes. So it should read just: FILE *fopencookie(void *, const char *, cookie_io_functions_t); Also note that while standard functions in POSIX can additionally be defined as function-like macros, they can't be object-like macros, so (*read), etc. are safe due to the parentheses. Rich
Powered by blists - more mailing lists
Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.