On 03/20/2012 10:01 AM, Tristan Gingold wrote:
I am starting to build fortran for VMS.
The first serious issue was with libgfortran/configure. It checks for several
math functions, but directly in libm using AC_CHECK_LIB.
But there is on such things as libm on VMS systems (thus requiring to define MATH_LIBRARY
as ""). Therefore all these tests fail,
resulting in a failure during libgfortran build.
I think the best way to test for the math function is to use AC_CHECK_DECLS as
hinted by the autoconf manual
(cf the AC_CHECK_DECLS example in
AC_CHECK_DECLS([j0], , , [[#include<math.h>]])
AC_CHECK_DECLS([[basename(char *)], [dirname(char *)]])
but I am not an autoconf expert.
I think that this change makes the AIX specific check for __clog obsolete, but
I haven't removed it.
With this change I was able to cross build libgfortran for VMS (ia64 and alpha).
I have also bootstrapped gcc for x86_64-darwin, without fortran regressions.
Ok for trunk ?
What you are doing here is to replace checks, which check for presence
of a symbol in a library (e.g. cos in libm.*) by checks for presence of
a symbol's declaration inside of a header.
This is something entirely different (This also reflects in
AC_CHECK_DECL by default providing HAVE_DECL_XXX defines).
Also note that it's not uncommon to have declarations inside of headers,
which are not present inside of a library.