libc/stdoutstream: restore the output method to fputc()

keep the default behavior for stdoutstream since the character
needs to flush every output

Signed-off-by: chao.an <anchao@xiaomi.com>

libs/libc/stdio/lib_rawsostream.c

@@ -46,9 +46,9 @@ static int rawoutstream_puts(FAR struct lib_outstream_s *this,
   FAR struct lib_rawoutstream_s *rthis =
                                 (FAR struct lib_rawoutstream_s *)this;
   int nwritten = 0;
-  int ret;
+  int ret = 0;
 
-  while (1)
+  while (nwritten != len)
     {
       ret = _NX_WRITE(rthis->fd, (FAR const char *)buf + nwritten,
                       len - nwritten);

libs/libc/stdio/lib_stdoutstream.c

@@ -32,49 +32,36 @@
  * Private Functions
  ****************************************************************************/
 
-/****************************************************************************
- * Name: stdoutstream_puts
- ****************************************************************************/
-
-static int stdoutstream_puts(FAR struct lib_outstream_s *this,
-                             FAR const void *buf, int len)
-{
-  FAR struct lib_stdoutstream_s *sthis =
-                               (FAR struct lib_stdoutstream_s *)this;
-  int nwritten = 0;
-  int ret;
-
-  DEBUGASSERT(this && sthis->stream);
-
-  while (1)
-    {
-      ret = fwrite((FAR char *)buf + nwritten,
-                    len - nwritten, 1, sthis->stream);
-      if (ret <= 0)
-        {
-          if (_NX_GETERRNO(ret) == EINTR)
-            {
-              continue;
-            }
-
-          break;
-        }
-
-      this->nput += ret;
-      nwritten   += ret;
-    }
-
-  return nwritten > 0 ? nwritten : ret;
-}
-
 /****************************************************************************
  * Name: stdoutstream_putc
  ****************************************************************************/
 
 static void stdoutstream_putc(FAR struct lib_outstream_s *this, int ch)
 {
-  char tmp = ch;
+  FAR struct lib_stdoutstream_s *sthis =
-  (void)stdoutstream_puts(this, &tmp, 1);
+                               (FAR struct lib_stdoutstream_s *)this;
+  int result;
+
+  DEBUGASSERT(this && sthis->stream);
+
+  /* Loop until the character is successfully transferred or an irrecoverable
+   * error occurs.
+   */
+
+  do
+    {
+      result = fputc(ch, sthis->stream);
+      if (result != EOF)
+        {
+          this->nput++;
+          return;
+        }
+
+      /* EINTR (meaning that fputc was interrupted by a signal) is the only
+       * recoverable error.
+       */
+    }
+  while (get_errno() == EINTR);
 }
 
 /****************************************************************************
@@ -119,7 +106,6 @@ void lib_stdoutstream(FAR struct lib_stdoutstream_s *outstream,
   /* Select the put operation */
 
   outstream->public.put = stdoutstream_putc;
-  outstream->public.puts = stdoutstream_puts;
 
   /* Select the correct flush operation.  This flush is only called when
    * a newline is encountered in the output stream.  However, we do not