Linux Device Drivers 3 examples

1 files changed, 44 insertions, 0 deletions

diff --git a/misc-progs/nbtest.c b/misc-progs/nbtest.c
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--- /dev/null
+++ b/misc-progs/nbtest.c
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+/*
+ * nbtest.c: read and write in non-blocking mode
+ * This should run with any Unix
+ *
+ * Copyright (C) 2001 Alessandro Rubini and Jonathan Corbet
+ * Copyright (C) 2001 O'Reilly & Associates
+ *
+ * The source code in this file can be freely used, adapted,
+ * and redistributed in source or binary form, so long as an
+ * acknowledgment appears in derived source files.  The citation
+ * should list that the code comes from the book "Linux Device
+ * Drivers" by Alessandro Rubini and Jonathan Corbet, published
+ * by O'Reilly & Associates.   No warranty is attached;
+ * we cannot take responsibility for errors or fitness for use.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <errno.h>
+
+char buffer[4096];
+
+int main(int argc, char **argv)
+{
+	int delay = 1, n, m = 0;
+
+	if (argc > 1)
+		delay=atoi(argv[1]);
+	fcntl(0, F_SETFL, fcntl(0,F_GETFL) | O_NONBLOCK); /* stdin */
+	fcntl(1, F_SETFL, fcntl(1,F_GETFL) | O_NONBLOCK); /* stdout */
+
+	while (1) {
+		n = read(0, buffer, 4096);
+		if (n >= 0)
+			m = write(1, buffer, n);
+		if ((n < 0 || m < 0) && (errno != EAGAIN))
+			break;
+		sleep(delay);
+	}
+	perror(n < 0 ? "stdin" : "stdout");
+	exit(1);
+}