1 files changed, 52 insertions, 0 deletions
diff --git a/system/doc/tutorial/port_driver.c b/system/doc/tutorial/port_driver.c
new file mode 100644
index 0000000000..d428d08ff3
--- /dev/null
+++ b/system/doc/tutorial/port_driver.c
@@ -0,0 +1,52 @@
+/* port_driver.c */
+
+#include <stdio.h>
+#include "erl_driver.h"
+
+typedef struct {
+    ErlDrvPort port;
+} example_data;
+
+static ErlDrvData example_drv_start(ErlDrvPort port, char *buff)
+{
+    example_data* d = (example_data*)driver_alloc(sizeof(example_data));
+    d->port = port;
+    return (ErlDrvData)d;
+}
+
+static void example_drv_stop(ErlDrvData handle)
+{
+    driver_free((char*)handle);
+}
+
+static void example_drv_output(ErlDrvData handle, char *buff, int bufflen)
+{
+    example_data* d = (example_data*)handle;
+    char fn = buff[0], arg = buff[1], res;
+    if (fn == 1) {
+      res = foo(arg);
+    } else if (fn == 2) {
+      res = bar(arg);
+    }
+    driver_output(d->port, &res, 1);
+}
+
+ErlDrvEntry example_driver_entry = {
+    NULL,			/* F_PTR init, N/A */
+    example_drv_start,		/* L_PTR start, called when port is opened */
+    example_drv_stop,		/* F_PTR stop, called when port is closed */
+    example_drv_output,		/* F_PTR output, called when erlang has sent */
+    NULL,			/* F_PTR ready_input, called when input descriptor ready */
+    NULL,			/* F_PTR ready_output, called when output descriptor ready */
+    "example_drv",		/* char *driver_name, the argument to open_port */
+    NULL,			/* F_PTR finish, called when unloaded */
+    NULL,			/* F_PTR control, port_command callback */
+    NULL,			/* F_PTR timeout, reserved */
+    NULL			/* F_PTR outputv, reserved */
+};
+
+DRIVER_INIT(example_drv) /* must match name in driver_entry */
+{
+    return &example_driver_entry;
+}
+