Imported Upstream version 7.44.0

[platform/upstream/curl.git] / docs / examples / multi-double.c

diff --git a/docs/examples/multi-double.c b/docs/examples/multi-double.c
index 91422e6..d652e7c 100644 (file)
--- a/docs/examples/multi-double.c
+++ b/docs/examples/multi-double.c
@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -19,6 +19,10 @@
  * KIND, either express or implied.
  *
  ***************************************************************************/
+/* <DESC>
+ * multi interface code doing two parallel HTTP transfers
+ * </DESC>
+ */
 #include <stdio.h>
 #include <string.h>
 
@@ -62,6 +66,7 @@ int main(void)
   do {
     struct timeval timeout;
     int rc; /* select() return code */
+    CURLMcode mc; /* curl_multi_fdset() return code */
 
     fd_set fdread;
     fd_set fdwrite;
@@ -88,15 +93,35 @@ int main(void)
     }
 
     /* get file descriptors from the transfers */
-    curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
+    mc = curl_multi_fdset(multi_handle, &fdread, &fdwrite, &fdexcep, &maxfd);
 
-    /* In a real-world program you OF COURSE check the return code of the
-       function calls.  On success, the value of maxfd is guaranteed to be
-       greater or equal than -1.  We call select(maxfd + 1, ...), specially in
-       case of (maxfd == -1), we call select(0, ...), which is basically equal
-       to sleep. */
+    if(mc != CURLM_OK)
+    {
+      fprintf(stderr, "curl_multi_fdset() failed, code %d.\n", mc);
+      break;
+    }
 
-    rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
+    /* On success the value of maxfd is guaranteed to be >= -1. We call
+       select(maxfd + 1, ...); specially in case of (maxfd == -1) there are
+       no fds ready yet so we call select(0, ...) --or Sleep() on Windows--
+       to sleep 100ms, which is the minimum suggested value in the
+       curl_multi_fdset() doc. */
+
+    if(maxfd == -1) {
+#ifdef _WIN32
+      Sleep(100);
+      rc = 0;
+#else
+      /* Portable sleep for platforms other than Windows. */
+      struct timeval wait = { 0, 100 * 1000 }; /* 100ms */
+      rc = select(0, NULL, NULL, NULL, &wait);
+#endif
+    }
+    else {
+      /* Note that on some platforms 'timeout' may be modified by select().
+         If you need access to the original value save a copy beforehand. */
+      rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
+    }
 
     switch(rc) {
     case -1: