Example of stream functions.

+/* GNU mailutils - a suite of utilities for electronic mail
+   Copyright (C) 1999, 2000, 2001 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 2, 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, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* This is an example program to illustrate the use of stream functions.
+   It connects to a remote HTTP server and prints the contents of its
+   index page */
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/select.h>
+
+#include <mailutils/mailutils.h>
+
+const char *wbuf = "GET / HTTP/1.0\r\n\r\n";
+char rbuf[1024];
+
+int
+main ()
+{
+  int ret, off = 0, fd;
+  stream_t stream;
+  size_t nb;
+  fd_set fds;
+
+  ret = tcp_stream_create (&stream, "www.gnu.org", 80, MU_STREAM_NONBLOCK);
+  if (ret != 0)
+    {
+      mu_error ( "tcp_stream_create: %s\n", mu_errstring (ret));
+      exit (EXIT_FAILURE);
+    }
+
+connect_again:
+  ret = stream_open (stream);
+  if (ret != 0)
+    {
+      if (ret == EAGAIN)
+        {
+          ret = stream_get_fd (stream, &fd);
+          if (ret != 0)
+            {
+              mu_error ( "stream_get_fd: %s\n", mu_errstring (ret));
+              exit (EXIT_FAILURE);
+            }
+          FD_ZERO (&fds);
+          FD_SET (fd, &fds);
+          select (fd + 1, NULL, &fds, NULL, NULL);
+          goto connect_again;
+        }
+      mu_error ( "stream_open: %s\n", mu_errstring (ret));
+      exit (EXIT_FAILURE);
+    }
+
+  ret = stream_get_fd (stream, &fd);
+  if (ret != 0)
+    {
+      mu_error ( "stream_get_fd: %s\n", mu_errstring (ret));
+      exit (EXIT_FAILURE);
+    }
+
+write_again:
+  ret = stream_write (stream, wbuf + off, strlen (wbuf), 0, &nb);
+  if (ret != 0)
+    {
+      if (ret == EAGAIN)
+        {
+          FD_ZERO (&fds);
+          FD_SET (fd, &fds);
+          select (fd + 1, NULL, &fds, NULL, NULL);
+          off += nb;
+          goto write_again;
+        }
+      mu_error ( "stream_write: %s\n", mu_errstring (ret));
+      exit (EXIT_FAILURE);
+    }
+
+  if (nb != strlen (wbuf))
+    {
+      mu_error ( "stream_write: %s\n", "nb != wbuf length");
+      exit (EXIT_FAILURE);
+    }
+
+  do
+    {
+      ret = stream_read (stream, rbuf, sizeof (rbuf), 0, &nb);
+      if (ret != 0)
+        {
+          if (ret == EAGAIN)
+            {
+              FD_ZERO (&fds);
+              FD_SET (fd, &fds);
+              select (fd + 1, &fds, NULL, NULL, NULL);
+            }
+          else
+            {
+              mu_error ( "stream_read: %s\n", mu_errstring (ret));
+              exit (EXIT_FAILURE);
+            }
+        }
+      write (2, rbuf, nb);
+    }
+  while (nb || ret == EAGAIN);
+
+  ret = stream_close (stream);
+  if (ret != 0)
+    {
+      mu_error ( "stream_close: %s\n", mu_errstring (ret));
+      exit (EXIT_FAILURE);
+    }
+
+  stream_destroy (&stream, NULL);
+  exit (EXIT_SUCCESS);
+}