[Global]: loading init

deps/curl/docs/examples/sendrecv.c

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+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 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
+ * are also available at https://curl.se/docs/copyright.html.
+ *
+ * You may opt to use, copy, modify, merge, publish, distribute and/or sell
+ * copies of the Software, and permit persons to whom the Software is
+ * furnished to do so, under the terms of the COPYING file.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ * SPDX-License-Identifier: curl
+ *
+ ***************************************************************************/
+/* <DESC>
+ * Demonstrate curl_easy_send() and curl_easy_recv() usage.
+ * </DESC>
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <curl/curl.h>
+
+/* Auxiliary function that waits on the socket. */
+static int wait_on_socket(curl_socket_t sockfd, int for_recv, long timeout_ms)
+{
+  struct timeval tv;
+  fd_set infd, outfd, errfd;
+  int res;
+
+  tv.tv_sec = timeout_ms / 1000;
+  tv.tv_usec = (int)(timeout_ms % 1000) * 1000;
+
+  FD_ZERO(&infd);
+  FD_ZERO(&outfd);
+  FD_ZERO(&errfd);
+
+/* Avoid this warning with pre-2020 Cygwin/MSYS releases:
+ * warning: conversion to 'long unsigned int' from 'curl_socket_t' {aka 'int'}
+ * may change the sign of the result [-Wsign-conversion]
+ */
+#if defined(__GNUC__) && defined(__CYGWIN__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsign-conversion"
+#endif
+  FD_SET(sockfd, &errfd); /* always check for error */
+
+  if(for_recv) {
+    FD_SET(sockfd, &infd);
+  }
+  else {
+    FD_SET(sockfd, &outfd);
+  }
+#if defined(__GNUC__) && defined(__CYGWIN__)
+#pragma GCC diagnostic pop
+#endif
+
+  /* select() returns the number of signalled sockets or -1 */
+  res = select((int)sockfd + 1, &infd, &outfd, &errfd, &tv);
+  return res;
+}
+
+int main(void)
+{
+  CURL *curl;
+  /* Minimalistic http request */
+  const char *request = "GET / HTTP/1.0\r\nHost: example.com\r\n\r\n";
+  size_t request_len = strlen(request);
+
+  /* A general note of caution here: if you are using curl_easy_recv() or
+     curl_easy_send() to implement HTTP or _any_ other protocol libcurl
+     supports "natively", you are doing it wrong and you should stop.
+
+     This example uses HTTP only to show how to use this API, it does not
+     suggest that writing an application doing this is sensible.
+  */
+
+  curl = curl_easy_init();
+  if(curl) {
+    CURLcode res;
+    curl_socket_t sockfd;
+    size_t nsent_total = 0;
+
+    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
+    /* Do not do the transfer - only connect to host */
+    curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1L);
+    res = curl_easy_perform(curl);
+
+    if(res != CURLE_OK) {
+      printf("Error: %s\n", curl_easy_strerror(res));
+      return 1;
+    }
+
+    /* Extract the socket from the curl handle - we will need it for
+       waiting. */
+    res = curl_easy_getinfo(curl, CURLINFO_ACTIVESOCKET, &sockfd);
+
+    if(res != CURLE_OK) {
+      printf("Error: %s\n", curl_easy_strerror(res));
+      return 1;
+    }
+
+    printf("Sending request.\n");
+
+    do {
+      /* Warning: This example program may loop indefinitely.
+       * A production-quality program must define a timeout and exit this loop
+       * as soon as the timeout has expired. */
+      size_t nsent;
+      do {
+        nsent = 0;
+        res = curl_easy_send(curl, request + nsent_total,
+            request_len - nsent_total, &nsent);
+        nsent_total += nsent;
+
+        if(res == CURLE_AGAIN && !wait_on_socket(sockfd, 0, 60000L)) {
+          printf("Error: timeout.\n");
+          return 1;
+        }
+      } while(res == CURLE_AGAIN);
+
+      if(res != CURLE_OK) {
+        printf("Error: %s\n", curl_easy_strerror(res));
+        return 1;
+      }
+
+      printf("Sent %lu bytes.\n", (unsigned long)nsent);
+
+    } while(nsent_total < request_len);
+
+    printf("Reading response.\n");
+
+    for(;;) {
+      /* Warning: This example program may loop indefinitely (see above). */
+      char buf[1024];
+      size_t nread;
+      do {
+        nread = 0;
+        res = curl_easy_recv(curl, buf, sizeof(buf), &nread);
+
+        if(res == CURLE_AGAIN && !wait_on_socket(sockfd, 1, 60000L)) {
+          printf("Error: timeout.\n");
+          return 1;
+        }
+      } while(res == CURLE_AGAIN);
+
+      if(res != CURLE_OK) {
+        printf("Error: %s\n", curl_easy_strerror(res));
+        break;
+      }
+
+      if(nread == 0) {
+        /* end of the response */
+        break;
+      }
+
+      printf("Received %lu bytes.\n", (unsigned long)nread);
+    }
+
+    /* always cleanup */
+    curl_easy_cleanup(curl);
+  }
+  return 0;
+}