1 files changed, 76 insertions, 0 deletions
diff --git a/lib/usleep.c b/lib/usleep.c
new file mode 100644
index 0000000..08a2251
--- /dev/null
+++ b/lib/usleep.c
@@ -0,0 +1,76 @@
+/* Pausing execution of the current thread.
+   Copyright (C) 2009-2023 Free Software Foundation, Inc.
+   Written by Eric Blake <ebb9@byu.net>, 2009.
+
+   This file is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as
+   published by the Free Software Foundation; either version 2.1 of the
+   License, or (at your option) any later version.
+
+   This file 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* This file is _intentionally_ light-weight.  Rather than using
+   select or nanosleep, both of which drag in external libraries on
+   some platforms, this merely rounds up to the nearest second if
+   usleep() does not exist.  If sub-second resolution is important,
+   then use a more powerful interface to begin with.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <unistd.h>
+
+#include <errno.h>
+
+#if defined _WIN32 && ! defined __CYGWIN__
+# define WIN32_LEAN_AND_MEAN  /* avoid including junk */
+# include <windows.h>
+#endif
+
+#ifndef HAVE_USLEEP
+# define HAVE_USLEEP 0
+#endif
+
+/* Sleep for MICRO microseconds, which can be greater than 1 second.
+   Return -1 and set errno to EINVAL on range error (about 4295
+   seconds), or 0 on success.  Interaction with SIGALARM is
+   unspecified.  */
+
+int
+usleep (useconds_t micro)
+#undef usleep
+{
+#if defined _WIN32 && ! defined __CYGWIN__
+  unsigned int milliseconds = micro / 1000;
+  if (sizeof milliseconds < sizeof micro && micro / 1000 != milliseconds)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+  if (micro % 1000)
+    milliseconds++;
+  Sleep (milliseconds);
+  return 0;
+#else
+  unsigned int seconds = micro / 1000000;
+  if (sizeof seconds < sizeof micro && micro / 1000000 != seconds)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+  if (!HAVE_USLEEP && micro % 1000000)
+    seconds++;
+  while ((seconds = sleep (seconds)) != 0);
+
+# if !HAVE_USLEEP
+#  define usleep(x) 0
+# endif
+  return usleep (micro % 1000000);
+#endif
+}