On Fri, Dec 21, 2018 at 11:40 AM Steven Rostedt <rost...@goodmis.org> wrote: > > OK, what about if we just use strlen() and say that this macro is not > safe for parameters with side effects.
I think gcc follows simple assignments just fine, and does the optimized strlen() for them too. So why not just do #define have_prefix(str,prefix) ({ \ const char *__pfx = prefix; \ size_t __pfxlen = strlen(__pfx); \ strncmp(str, __pfx, __pfxlen) ? 0 : __pfxlen); }) and be done with it safely? The above is ENTIRELY untested. Linus