1 files changed, 63 insertions, 0 deletions
diff --git a/src/port/pgsleep.c b/src/port/pgsleep.c
new file mode 100644
index 0000000..d6d5136
--- /dev/null
+++ b/src/port/pgsleep.c
@@ -0,0 +1,63 @@
+/*-------------------------------------------------------------------------
+ *
+ * pgsleep.c
+ *	   Portable delay handling.
+ *
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ *
+ * src/port/pgsleep.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "c.h"
+
+#include <unistd.h>
+#include <sys/time.h>
+#ifdef HAVE_SYS_SELECT_H
+#include <sys/select.h>
+#endif
+
+/*
+ * In a Windows backend, we don't use this implementation, but rather
+ * the signal-aware version in src/backend/port/win32/signal.c.
+ */
+#if defined(FRONTEND) || !defined(WIN32)
+
+/*
+ * pg_usleep --- delay the specified number of microseconds.
+ *
+ * NOTE: although the delay is specified in microseconds, the effective
+ * resolution is only 1/HZ, or 10 milliseconds, on most Unixen.  Expect
+ * the requested delay to be rounded up to the next resolution boundary.
+ *
+ * On machines where "long" is 32 bits, the maximum delay is ~2000 seconds.
+ *
+ * CAUTION: the behavior when a signal arrives during the sleep is platform
+ * dependent.  On most Unix-ish platforms, a signal does not terminate the
+ * sleep; but on some, it will (the Windows implementation also allows signals
+ * to terminate pg_usleep).  And there are platforms where not only does a
+ * signal not terminate the sleep, but it actually resets the timeout counter
+ * so that the sleep effectively starts over!  It is therefore rather hazardous
+ * to use this for long sleeps; a continuing stream of signal events could
+ * prevent the sleep from ever terminating.  Better practice for long sleeps
+ * is to use WaitLatch() with a timeout.
+ */
+void
+pg_usleep(long microsec)
+{
+	if (microsec > 0)
+	{
+#ifndef WIN32
+		struct timeval delay;
+
+		delay.tv_sec = microsec / 1000000L;
+		delay.tv_usec = microsec % 1000000L;
+		(void) select(0, NULL, NULL, NULL, &delay);
+#else
+		SleepEx((microsec < 500 ? 1 : (microsec + 500) / 1000), FALSE);
+#endif
+	}
+}
+
+#endif							/* defined(FRONTEND) || !defined(WIN32) */