--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2011-10-08  Bruno Haible  <bruno@clisp.org>
+
+	New module 'sqrtf'.
+	* lib/math.in.h (sqrtf): New declaration.
+	* lib/sqrtf.c: New file.
+	* m4/sqrtf.m4: New file.
+	* m4/math_h.m4 (gl_MATH_H): Test whether sqrtf is declared.
+	(gl_MATH_H_DEFAULTS): Initialize GNULIB_SQRTF, HAVE_SQRTF.
+	* modules/math (Makefile.am): Substitute GNULIB_SQRTF, HAVE_SQRTF.
+	* modules/sqrtf: New file.
+	* tests/test-math-c++.cc: Check the declaration of sqrtf.
+	* doc/posix-functions/sqrtf.texi: Mention the new module.
+
 2011-10-08  Bruno Haible  <bruno@clisp.org>
 
 	Tests: Avoid link failures w.r.t. libintl.

--- a/doc/posix-functions/sqrtf.texi
+++ b/doc/posix-functions/sqrtf.texi
@@ -4,14 +4,10 @@
 
 POSIX specification:@* @url{http://www.opengroup.org/onlinepubs/9699919799/functions/sqrtf.html}
 
-Gnulib module: ---
+Gnulib module: sqrtf
 
 Portability problems fixed by Gnulib:
 @itemize
-@end itemize
-
-Portability problems not fixed by Gnulib:
-@itemize
 @item
 This function is missing on some platforms:
 Minix 3.1.8, AIX 5.1, Solaris 9.
@@ -19,3 +15,7 @@
 This function is only defined as a macro with arguments on some platforms:
 MSVC 9.
 @end itemize
+
+Portability problems not fixed by Gnulib:
+@itemize
+@end itemize

--- a/lib/math.in.h
+++ b/lib/math.in.h
@@ -600,6 +600,21 @@
 #endif
 
 
+#if @GNULIB_SQRTF@
+# if !@HAVE_SQRTF@
+#  undef sqrtf
+_GL_FUNCDECL_SYS (sqrtf, float, (float x));
+# endif
+_GL_CXXALIAS_SYS (sqrtf, float, (float x));
+_GL_CXXALIASWARN (sqrtf);
+#elif defined GNULIB_POSIXCHECK
+# undef sqrtf
+# if HAVE_RAW_DECL_SQRTF
+_GL_WARN_ON_USE (sqrtf, "sqrtf is unportable - "
+                 "use gnulib module sqrtf for portability");
+# endif
+#endif
+
 #if @GNULIB_SQRTL@
 # if !@HAVE_SQRTL@ || !@HAVE_DECL_SQRTL@
 _GL_FUNCDECL_SYS (sqrtl, long double, (long double x));

new file mode 100644
--- /dev/null
+++ b/lib/sqrtf.c
@@ -0,0 +1,26 @@
+/* Square root.
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <math.h>
+
+float
+sqrtf (float x)
+{
+  return (float) sqrt ((double) x);
+}

--- a/m4/math_h.m4
+++ b/m4/math_h.m4
@@ -1,4 +1,4 @@
-# math_h.m4 serial 31
+# math_h.m4 serial 32
 dnl Copyright (C) 2007-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -41,7 +41,7 @@
   gl_WARN_ON_USE_PREPARE([[#include <math.h>]],
     [acosl asinl atanl ceilf ceill cosl expl fabsf floorf floorl fmodf
      frexpf frexpl
-     ldexpf ldexpl logb logl modff round roundf roundl sinl sqrtl
+     ldexpf ldexpl logb logl modff round roundf roundl sinl sqrtf sqrtl
      tanl trunc truncf truncl])
 ])
 
@@ -88,6 +88,7 @@
   GNULIB_ROUNDL=0;   AC_SUBST([GNULIB_ROUNDL])
   GNULIB_SIGNBIT=0;  AC_SUBST([GNULIB_SIGNBIT])
   GNULIB_SINL=0;     AC_SUBST([GNULIB_SINL])
+  GNULIB_SQRTF=0;    AC_SUBST([GNULIB_SQRTF])
   GNULIB_SQRTL=0;    AC_SUBST([GNULIB_SQRTL])
   GNULIB_TANL=0;     AC_SUBST([GNULIB_TANL])
   GNULIB_TRUNC=0;    AC_SUBST([GNULIB_TRUNC])
@@ -109,6 +110,7 @@
   HAVE_LOGL=1;                 AC_SUBST([HAVE_LOGL])
   HAVE_MODFF=1;                AC_SUBST([HAVE_MODFF])
   HAVE_SINL=1;                 AC_SUBST([HAVE_SINL])
+  HAVE_SQRTF=1;                AC_SUBST([HAVE_SQRTF])
   HAVE_SQRTL=1;                AC_SUBST([HAVE_SQRTL])
   HAVE_TANL=1;                 AC_SUBST([HAVE_TANL])
   HAVE_DECL_ACOSL=1;           AC_SUBST([HAVE_DECL_ACOSL])

new file mode 100644
--- /dev/null
+++ b/m4/sqrtf.m4
@@ -0,0 +1,25 @@
+# sqrtf.m4 serial 1
+dnl Copyright (C) 2011 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_SQRTF],
+[
+  AC_REQUIRE([gl_MATH_H_DEFAULTS])
+  AC_REQUIRE([gl_FUNC_SQRT])
+
+  dnl Test whether sqrtf() exists. Assume that sqrtf(), if it exists, is
+  dnl defined in the same library as sqrt().
+  save_LIBS="$LIBS"
+  LIBS="$LIBS $SQRT_LIBM"
+  AC_CHECK_FUNCS([sqrtf])
+  LIBS="$save_LIBS"
+  if test $ac_cv_func_sqrtf = yes; then
+    SQRTF_LIBM="$SQRT_LIBM"
+  else
+    HAVE_SQRTF=0
+    SQRTF_LIBM="$SQRT_LIBM"
+  fi
+  AC_SUBST([SQRTF_LIBM])
+])

--- a/modules/math
+++ b/modules/math
@@ -60,6 +60,7 @@
 	      -e 's/@''GNULIB_ROUNDL''@/$(GNULIB_ROUNDL)/g' \
 	      -e 's/@''GNULIB_SIGNBIT''@/$(GNULIB_SIGNBIT)/g' \
 	      -e 's/@''GNULIB_SINL''@/$(GNULIB_SINL)/g' \
+	      -e 's/@''GNULIB_SQRTF''@/$(GNULIB_SQRTF)/g' \
 	      -e 's/@''GNULIB_SQRTL''@/$(GNULIB_SQRTL)/g' \
 	      -e 's/@''GNULIB_TANL''@/$(GNULIB_TANL)/g' \
 	      -e 's/@''GNULIB_TRUNC''@/$(GNULIB_TRUNC)/g' \
@@ -81,6 +82,7 @@
 	      -e 's|@''HAVE_LOGL''@|$(HAVE_LOGL)|g' \
 	      -e 's|@''HAVE_MODFF''@|$(HAVE_MODFF)|g' \
 	      -e 's|@''HAVE_SINL''@|$(HAVE_SINL)|g' \
+	      -e 's|@''HAVE_SQRTF''@|$(HAVE_SQRTF)|g' \
 	      -e 's|@''HAVE_SQRTL''@|$(HAVE_SQRTL)|g' \
 	      -e 's|@''HAVE_TANL''@|$(HAVE_TANL)|g' \
 	      -e 's|@''HAVE_DECL_ACOSL''@|$(HAVE_DECL_ACOSL)|g' \

new file mode 100644
--- /dev/null
+++ b/modules/sqrtf
@@ -0,0 +1,31 @@
+Description:
+sqrtf() function: square root.
+
+Files:
+lib/sqrtf.c
+m4/sqrtf.m4
+
+Depends-on:
+math
+sqrt            [test $HAVE_SQRTF = 0]
+
+configure.ac:
+gl_FUNC_SQRTF
+if test $HAVE_SQRTF = 0; then
+  AC_LIBOBJ([sqrtf])
+fi
+gl_MATH_MODULE_INDICATOR([sqrtf])
+
+Makefile.am:
+
+Include:
+<math.h>
+
+Link:
+$(SQRTF_LIBM)
+
+License:
+LGPL
+
+Maintainer:
+Bruno Haible

--- a/tests/test-math-c++.cc
+++ b/tests/test-math-c++.cc
@@ -72,6 +72,9 @@
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::rint, double, (double));
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::sin, double, (double));
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::sinh, double, (double));
+#if GNULIB_TEST_SQRTF
+SIGNATURE_CHECK (GNULIB_NAMESPACE::sqrtf, float, (float));
+#endif
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::sqrt, double, (double));
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::tan, double, (double));
 //SIGNATURE_CHECK (GNULIB_NAMESPACE::tanh, double, (double));