X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=m4%2Fcopysignf.m4;h=293bf456132ecf0aeb727aeb87b46ca031980055;hb=4f044de87e05bee61005c48bb93f3bb9a4b76461;hp=4f2825cb4326411c180cbc6e1999876db644b60a;hpb=bf6909e5ca400414ed0730b7f64e48d04993936e;p=gnulib.git

diff --git a/m4/copysignf.m4 b/m4/copysignf.m4
index 4f2825cb4..293bf4561 100644
--- a/m4/copysignf.m4
+++ b/m4/copysignf.m4
@@ -1,4 +1,4 @@
-# copysignf.m4 serial 2
+# copysignf.m4 serial 3
 dnl Copyright (C) 2011-2012 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -12,10 +12,22 @@ AC_DEFUN([gl_FUNC_COPYSIGNF],
   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
 
   dnl Determine COPYSIGNF_LIBM.
-  gl_MATHFUNC([copysignf], [float], [(float, float)])
-  if test $gl_cv_func_copysignf_no_libm = no \
-     && test $gl_cv_func_copysignf_in_libm = no; then
+  gl_MATHFUNC([copysignf], [float], [(float, float)],
+    [extern
+     #ifdef __cplusplus
+     "C"
+     #endif
+     float copysignf (float, float);
+    ])
+  if test $gl_cv_func_copysignf_no_libm = yes \
+     || test $gl_cv_func_copysignf_in_libm = yes; then
+    HAVE_COPYSIGNF=1
+    dnl Also check whether it's declared.
+    dnl IRIX 6.5 has copysignf() in libm but doesn't declare it in <math.h>.
+    AC_CHECK_DECL([copysignf], , [HAVE_DECL_COPYSIGNF=0], [[#include <math.h>]])
+  else
     HAVE_COPYSIGNF=0
+    HAVE_DECL_COPYSIGNF=0
     COPYSIGNF_LIBM=
   fi
   AC_SUBST([COPYSIGNF_LIBM])