Re: isinf

[Hiroshi Fujishima <hiroshi.fujishima@gmail.com>]

Andreas Schwab <schwab@suse.de> writes:

> Why not just use AC_HAVE_FUNCS(isinf)?  IIUC this is part of a configure
> script, although whether it is autoconf generated is not clear so far.

Though I don't know the why, rrdtool-1.2.10/configure.ac has the
following macro.

dnl HP-UX 11.00 does not have finite but does have isfinite as a macro so we need
dnl actual code to check if this works
AC_CHECK_FUNCS(fpclassify, ,
  [AC_MSG_CHECKING(for fpclassify with <math.h>)
    AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <math.h>]], [[float f = 0.0; fpclassify(f)]])],[AC_MSG_RESULT(yes)
      AC_DEFINE(HAVE_FPCLASSIFY)],[AC_MSG_RESULT(no)])])
AC_CHECK_FUNCS(finite, ,
  [AC_CHECK_FUNCS(isfinite, ,
    [AC_MSG_CHECKING(for isfinite with <math.h>)
    AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <math.h>]], [[float f = 0.0; isfinite(f)]])],[AC_MSG_RESULT(yes)
      AC_DEFINE(HAVE_ISFINITE)],[AC_MSG_RESULT(no)])])])
AC_CHECK_FUNCS(isinf, ,
  [AC_MSG_CHECKING(for isinf with <math.h>)
    AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <math.h>]], [[float f = 0.0; int x = isinf(f)]])],[AC_MSG_RESULT(yes)
      AC_DEFINE(HAVE_ISINF)],[AC_MSG_RESULT(no)])])

-- 
Hiroshi Fujishima