1 files changed, 38 insertions, 0 deletions
diff --git a/m4/printf-frexp.m4 b/m4/printf-frexp.m4
new file mode 100644
index 0000000..2ffa1d7
--- /dev/null
+++ b/m4/printf-frexp.m4
@@ -0,0 +1,38 @@
+# printf-frexp.m4 serial 5
+dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Check how to define printf_frexp() without linking with libm.
+
+AC_DEFUN([gl_FUNC_PRINTF_FREXP],
+[
+  AC_REQUIRE([gl_CHECK_FREXP_NO_LIBM])
+  if test $gl_cv_func_frexp_no_libm = yes; then
+    gl_FUNC_FREXP_WORKS
+    case "$gl_cv_func_frexp_works" in
+      *yes)
+        AC_DEFINE([HAVE_FREXP_IN_LIBC], [1],
+          [Define if the frexp function is available in libc.])
+        ;;
+    esac
+  fi
+
+  AC_CACHE_CHECK([whether ldexp can be used without linking with libm],
+    [gl_cv_func_ldexp_no_libm],
+    [
+      AC_LINK_IFELSE(
+        [AC_LANG_PROGRAM(
+           [[#include <math.h>
+             double x;
+             int y;]],
+           [[return ldexp (x, y) < 1;]])],
+        [gl_cv_func_ldexp_no_libm=yes],
+        [gl_cv_func_ldexp_no_libm=no])
+    ])
+  if test $gl_cv_func_ldexp_no_libm = yes; then
+    AC_DEFINE([HAVE_LDEXP_IN_LIBC], [1],
+      [Define if the ldexp function is available in libc.])
+  fi
+])