> > > Patch #5 and beyond: Further optimization work. > > > > As one of the next steps I'd like to make this feature available > > to user-defined sprintf-like functions decorated with attribute > > format. To do that, I'm thinking of adding either a fourth > > (optional) argument to attribute format printf indicating which > > of the function arguments is the destination buffer (to compute > > its size), or perhaps a new attribute under its own name. I'm > > actually leaning toward latter since I think it could be used > > in other contexts as well. I welcome comments and suggestions > > on this idea. > Whichever we think will be easier to use and thus encourage folks to > annotate their code properly :-)
So, sort of related I've been thinking about writing C++ string building classes some lately. Where you'd have a fixed length buffer and a pointer to the next buffer (so a degenerate rope with only one side of the tree). One use case for such a thing is building up strings of assembly to output in gcc. however one somewhat awkward bit is that we often format assembly with printf, which isn't really great for this use case, because you need to deal with the case the current buffer only has space for part of the string you are formatting. So it would be nice to have something like an interuptable printf that tells you where in the string it stopped formatting, and allows you to continue from there with a new buffer. It also seems worth noting that in C++11 you can actually write a printf that is typesafe without the format attributes for example Tom has one here https://github.com/tromey/typesafe-printf. I'm not sure putting such a thing in libc for C++ programs is a great idea because of compile time costs, but its tempting. Trev
