Restore lib_sprintf(). It was removed because I thought was not used. But I was wrong; there is logic in drivers/syslog that depends on lib_sprintf().

This commits reverts a part of commit c271151d57.  That commit also removed lib_sscanf() which really is not needed.

include/nuttx/streams.h

@@ -442,6 +442,17 @@ int lib_noflush(FAR struct lib_outstream_s *stream);
 
 int lib_snoflush(FAR struct lib_sostream_s *this);
 
+/****************************************************************************
+ * Name: lib_sprintf
+ *
+ * Description:
+ *  Stream-oriented implementation of sprintf.  Used only by the SYSLOG.
+ *
+ ****************************************************************************/
+
+int lib_sprintf(FAR struct lib_outstream_s *obj,
+                FAR const IPTR char *fmt, ...);
+
 /****************************************************************************
  * Name: lib_vsprintf
  *

libs/libc/stdio/Make.defs

@@ -1,7 +1,7 @@
 ############################################################################
 # libs/libc/stdio/Make.defs
 #
-#   Copyright (C) 2011-2014 Gregory Nutt. All rights reserved.
+#   Copyright (C) 2011-2014, 2019 Gregory Nutt. All rights reserved.
 #   Author: Gregory Nutt <gnutt@nuttx.org>
 #
 # Redistribution and use in source and binary forms, with or without
@@ -37,8 +37,8 @@
 # This first group of C files do not depend on having C streams.
 
 CSRCS += lib_fileno.c lib_printf.c lib_sprintf.c lib_asprintf.c
-CSRCS += lib_snprintf.c lib_vsprintf.c lib_vasprintf.c lib_vsnprintf.c
+CSRCS += lib_snprintf.c lib_libsprintf.c lib_vsprintf.c lib_vasprintf.c
-CSRCS += lib_dprintf.c lib_vdprintf.c
+CSRCS += lib_vsnprintf.c lib_dprintf.c lib_vdprintf.c
 CSRCS += lib_meminstream.c lib_memoutstream.c lib_memsistream.c
 CSRCS += lib_memsostream.c lib_lowoutstream.c
 CSRCS += lib_zeroinstream.c lib_nullinstream.c lib_nulloutstream.c

libs/libc/stdio/lib_libsprintf.c

@@ -0,0 +1,63 @@
+/****************************************************************************
+ * libs/libc/stdio/lib_libsprintf.c
+ *
+ *   Copyright (C) 2007-2009, 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdio.h>
+#include "libc.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: lib_sprintf
+ ****************************************************************************/
+
+int lib_sprintf(FAR struct lib_outstream_s *obj, FAR const IPTR char *fmt,
+                ...)
+{
+  va_list ap;
+  int     n;
+
+  /* Let lib_vsprintf do the real work */
+
+  va_start(ap, fmt);
+  n = lib_vsprintf(obj, fmt, ap);
+  va_end(ap);
+  return n;
+}