On Fri, Apr 20, 2012 at 3:54 PM, Petr Baudis <pa...@ucw.cz> wrote: > On Fri, Apr 20, 2012 at 01:11:34PM -0700, H.J. Lu wrote: >> On Fri, Apr 20, 2012 at 12:50 PM, Roland McGrath <rol...@hack.frob.com> >> wrote: >> > Please provide an example that illustrates why you think you need this. >> > >> >> Currently we use weak undefined symbol, foo, to do >> >> if (&foo != 0) >> foo is defined. >> else >> foo isn't defined. >> >> We want is to define foo as a secondary symbol so that >> we can always use foo without checking. If there is a primary >> one in a .o file and .so file, we will get the primary one, >> otherwise, we will use the secondary one. > > This is still a very general example. Does this concern a particular > software package?
We have a compiler optimization feature which requires a backup definition just in case that the primary one doesn't exist in an archive or a DSO. > Couldn't you use IFUNC to perform the if-statement above and supply > the proper function? No. -- H.J.
