http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47032
--- Comment #9 from Steve Kargl <sgk at troutmask dot apl.washington.edu> 2011-02-08 20:49:04 UTC --- On Tue, Feb 08, 2011 at 08:43:33PM +0000, pogma at gcc dot gnu.org wrote: > --- Comment #8 from Peter O'Gorman <pogma at gcc dot gnu.org> 2011-02-08 > 20:43:18 UTC --- > (In reply to comment #7) > > (In reply to comment #3) > > > libgfortran/configure.ac has lines of the form (note I wrapped the line) > > > > > > AC_CHECK_LIB([m],[copysignl],[AC_DEFINE([HAVE_COPYSIGNL],[1],\ > > > [libm includes copysignl])]) > > > > > > So, configure is already checking if libm contains the > > > the "long double functions". The problem appears to be > > > that AC_CHECK_LIB is a compile only test, and these tests > > > appear to pass on AIX. > > > > AC_CHECK_LIB uses a link test, not a compile test. > > As far as I can tell the problem is that the configure tests for long double > functions don't #include <math.h>, changing the AC_CHECK_LIB to AC_LINK_IFELSE > that #includes math.h and uses the symbol should give correct results. > So, for the AC_CHECK_LIB line above, what does the AC_LINK_IFELSE patch look like.
