--- a/doc/functions/floor.texi
+++ b/doc/functions/floor.texi
@@ -4,7 +4,7 @@
 
 POSIX specification: @url{http://www.opengroup.org/susv3xsh/floor.html}
 
-Gnulib module: ---
+Gnulib module: floor
 
 Portability problems fixed by Gnulib:
 @itemize

new file mode 100644
--- /dev/null
+++ b/m4/floor.m4
@@ -0,0 +1,36 @@
+# floor.m4 serial 1
+dnl Copyright (C) 2007 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.
+
+AC_DEFUN([gl_FUNC_FLOOR],
+[
+  dnl Test whether floor() can be used without libm.
+  FLOOR_LIBM=?
+  AC_TRY_LINK([
+     #ifndef __NO_MATH_INLINES
+     # define __NO_MATH_INLINES 1 /* for glibc */
+     #endif
+     #include <math.h>
+     double x;],
+    [x = floor(x);],
+    [FLOOR_LIBM=])
+  if test "$FLOOR_LIBM" = "?"; then
+    save_LIBS="$LIBS"
+    LIBS="$LIBS -lm"
+    AC_TRY_LINK([
+       #ifndef __NO_MATH_INLINES
+       # define __NO_MATH_INLINES 1 /* for glibc */
+       #endif
+       #include <math.h>
+       double x;],
+      [x = floor(x);],
+      [FLOOR_LIBM="-lm"])
+    LIBS="$save_LIBS"
+  fi
+  if test "$FLOOR_LIBM" = "?"; then
+    FLOOR_LIBM=
+  fi
+  AC_SUBST([FLOOR_LIBM])
+])

new file mode 100644
--- /dev/null
+++ b/modules/floor
@@ -0,0 +1,26 @@
+Description:
+floor() function: round towards negative infinity.
+
+Files:
+m4/floor.m4
+
+Depends-on:
+math
+
+configure.ac:
+gl_FUNC_FLOOR
+
+Makefile.am:
+
+Include:
+<math.h>
+
+Link:
+$(FLOOR_LIBM)
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible
+