--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/curl/docs/examples/threaded-ssl.c	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,166 @@
+/***************************************************************************
+ *                                  _   _ ____  _
+ *  Project                     ___| | | |  _ \| |
+ *                             / __| | | | |_) | |
+ *                            | (__| |_| |  _ <| |___
+ *                             \___|\___/|_| \_\_____|
+ *
+ * Copyright (C) 1998 - 2017, 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.haxx.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.
+ *
+ ***************************************************************************/
+/* <DESC>
+ * Show the required mutex callback setups for GnuTLS and OpenSSL when using
+ * libcurl multi-threaded.
+ * </DESC>
+ */
+/* A multi-threaded example that uses pthreads and fetches 4 remote files at
+ * once over HTTPS. The lock callbacks and stuff assume OpenSSL <1.1 or GnuTLS
+ * (libgcrypt) so far.
+ *
+ * OpenSSL docs for this:
+ *   https://www.openssl.org/docs/man1.0.2/man3/CRYPTO_num_locks.html
+ * gcrypt docs for this:
+ *   https://gnupg.org/documentation/manuals/gcrypt/Multi_002dThreading.html
+ */
+
+#define USE_OPENSSL /* or USE_GNUTLS accordingly */
+
+#include <stdio.h>
+#include <pthread.h>
+#include <curl/curl.h>
+
+#define NUMT 4
+
+/* we have this global to let the callback get easy access to it */
+static pthread_mutex_t *lockarray;
+
+#ifdef USE_OPENSSL
+#include <openssl/crypto.h>
+static void lock_callback(int mode, int type, char *file, int line)
+{
+  (void)file;
+  (void)line;
+  if(mode & CRYPTO_LOCK) {
+    pthread_mutex_lock(&(lockarray[type]));
+  }
+  else {
+    pthread_mutex_unlock(&(lockarray[type]));
+  }
+}
+
+static unsigned long thread_id(void)
+{
+  unsigned long ret;
+
+  ret = (unsigned long)pthread_self();
+  return ret;
+}
+
+static void init_locks(void)
+{
+  int i;
+
+  lockarray = (pthread_mutex_t *)OPENSSL_malloc(CRYPTO_num_locks() *
+                                                sizeof(pthread_mutex_t));
+  for(i = 0; i<CRYPTO_num_locks(); i++) {
+    pthread_mutex_init(&(lockarray[i]), NULL);
+  }
+
+  CRYPTO_set_id_callback((unsigned long (*)())thread_id);
+  CRYPTO_set_locking_callback((void (*)())lock_callback);
+}
+
+static void kill_locks(void)
+{
+  int i;
+
+  CRYPTO_set_locking_callback(NULL);
+  for(i = 0; i<CRYPTO_num_locks(); i++)
+    pthread_mutex_destroy(&(lockarray[i]));
+
+  OPENSSL_free(lockarray);
+}
+#endif
+
+#ifdef USE_GNUTLS
+#include <gcrypt.h>
+#include <errno.h>
+
+GCRY_THREAD_OPTION_PTHREAD_IMPL;
+
+void init_locks(void)
+{
+  gcry_control(GCRYCTL_SET_THREAD_CBS);
+}
+
+#define kill_locks()
+#endif
+
+/* List of URLs to fetch.*/
+const char * const urls[]= {
+  "https://www.example.com/",
+  "https://www2.example.com/",
+  "https://www3.example.com/",
+  "https://www4.example.com/",
+};
+
+static void *pull_one_url(void *url)
+{
+  CURL *curl;
+
+  curl = curl_easy_init();
+  curl_easy_setopt(curl, CURLOPT_URL, url);
+  /* this example doesn't verify the server's certificate, which means we
+     might be downloading stuff from an impostor */
+  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYPEER, 0L);
+  curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
+  curl_easy_perform(curl); /* ignores error */
+  curl_easy_cleanup(curl);
+
+  return NULL;
+}
+
+int main(int argc, char **argv)
+{
+  pthread_t tid[NUMT];
+  int i;
+  (void)argc; /* we don't use any arguments in this example */
+  (void)argv;
+
+  /* Must initialize libcurl before any threads are started */
+  curl_global_init(CURL_GLOBAL_ALL);
+
+  init_locks();
+
+  for(i = 0; i< NUMT; i++) {
+    int error = pthread_create(&tid[i],
+                               NULL, /* default attributes please */
+                               pull_one_url,
+                               (void *)urls[i]);
+    if(0 != error)
+      fprintf(stderr, "Couldn't run thread number %d, errno %d\n", i, error);
+    else
+      fprintf(stderr, "Thread %d, gets %s\n", i, urls[i]);
+  }
+
+  /* now wait for all threads to terminate */
+  for(i = 0; i< NUMT; i++) {
+    pthread_join(tid[i], NULL);
+    fprintf(stderr, "Thread %d terminated\n", i);
+  }
+
+  kill_locks();
+
+  return 0;
+}