On Thu, 2008-03-06 at 11:55 +0100, Johannes Schindelin wrote: > Hi, > > On Thu, 6 Mar 2008, Reece Dunn wrote: > > > On 06/03/2008, Mike Hommey <mh@xxxxxxxxxxxx> wrote: > > > On Thu, Mar 06, 2008 at 02:14:43AM +0100, Johannes Schindelin wrote: > > > > > > > > The most common use of addf() was to init a strbuf and addf() right > > > > away. Since it is so common, it makes sense to have a function > > > > strbuf_initf() to wrap both calls into one. > > > > > > > > Unfortunately, C (and cpp) has no way to make this easy without > > > > code duplication, as we need to va_init() in strbuf_addf() possibly > > > > a few times. So the code for addf() is copied. Fortunately, the > > > > code is pretty short, so not too much had to be copied as-is. > > > > > > > > > The problem with code duplication is not about code size, but more > > > about not forgetting to fix bugs in all incarnations of the duplicated > > > code. > > > > > > Is it so ugly to use a macro ? > > > > Why not have a strbuf_vaddf and strbuf_vinitf that take a va_arg as a > > parameter. This would mean that you don't have code duplication, and it > > is flexible enough if you want to add more customisations in the future. > > No macro needed. This is what the printf/scanf family of functions do. > > The problem is that we have to restart va_list() if the buffer was too > small. I think we've spent more time debating va_copy than it would take for somebody to just lift the implementation and checks from something like glib. But the recent patch for vsnprintf[1] doesn't actually fix the problem of reusing va_args in the general case; the va_list argument, ap, is undefined after the vsnprintf() call, yet it calls it in a loop. Just bite the bullet and pull in va_copy. Of course, I'm just adding to the debate here and not sending patches :/ > So your suggestion is out, unless you suggest to implement the whole > printf mechanism... which I hope you're not. It's not a terrible idea, honestly. There are several mature vsnprintf implementations out there under friendly licenses. We could just stick it in compat/. It's the only way to do reliable, cross platform vsnprintf, in my experience. And the issue with %I64u vs %llu could be handle by implementing both, as Wayne Davison suggests. Kristian [1] Message-Id: 200803051646.13343.michal.rokos@xxxxxxxxxxx from Michal Rokos -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
