On 2013-01-08 20:27, Stefano Lattarini wrote: > On 01/08/2013 04:29 PM, Eric Blake wrote: >> On 01/08/2013 08:15 AM, Stefano Lattarini wrote: >>> In addition, AM_PROG_CC_C_O is not required by >>> projects that don't care about catering to inferior compilers. >> >> How much speed penalty and configure bloat are we talking about by >> allowing projects to omit the use of this macro if they don't care about >> inferior compilers? >> > Almost zero bloat. The code simply re-uses a cache variable set by > AC_PROG_CC, and, *for losing compilers only*, plays some dirty but > inexpensive tricks with $CC redefinition.
Not quite, the cache variable is from AC_PROG_CC_C_O which is is not invoked by AC_PROG_CC, at least I don't think so? AM_PROG_CC_C_O requires AC_PROG_CC_C_O so it costs a couple of extra compile tests. Not that I'm complaining if those tests are always performed though, just trying to keep the arguments honest... (but again, I haven't actually checked if AC_PROG_CC triggers AC_PROG_CC_C_O) Cheers, Peter
