From: Michael Gernoth <michael@gernoth.net>
Date: Sun, 7 Jul 2013 20:04:56 +0000 (+0200)
Subject: add and export function to send only a null frame
X-Git-Tag: v0.100~76
X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/hmcfgusb/commitdiff_plain/2a6eaefc7786a666d27c52a8e9bb0c1c4aeb2843

add and export function to send only a null frame
---

diff --git a/hmcfgusb.c b/hmcfgusb.c
index 1ba9b24..ce8c595 100644
--- a/hmcfgusb.c
+++ b/hmcfgusb.c
@@ -140,6 +140,20 @@ static libusb_device_handle *hmcfgusb_find() {
 	return NULL;
 }
 
+int hmcfgusb_send_null_frame(struct hmcfgusb_dev *usbdev)
+{
+	int err;
+	int cnt;
+
+	err = libusb_interrupt_transfer(usbdev->usb_devh, EP_OUT, NULL, 0, &cnt, USB_TIMEOUT);
+	if (err) {
+		fprintf(stderr, "Can't send data: %s\n", usb_strerror(err));
+		return 0;
+	}
+
+	return 1;
+}
+
 int hmcfgusb_send(struct hmcfgusb_dev *usbdev, unsigned char* send_data, int len, int done)
 {
 	int err;
@@ -159,9 +173,7 @@ int hmcfgusb_send(struct hmcfgusb_dev *usbdev, unsigned char* send_data, int len
 	}
 
 	if (done) {
-		err = libusb_interrupt_transfer(usbdev->usb_devh, EP_OUT, send_data, 0, &cnt, USB_TIMEOUT);
-		if (err) {
-			fprintf(stderr, "Can't send data: %s\n", usb_strerror(err));
+		if (!hmcfgusb_send_null_frame(usbdev)) {
 			return 0;
 		}
 	}
diff --git a/hmcfgusb.h b/hmcfgusb.h
index 8a0751a..e50f831 100644
--- a/hmcfgusb.h
+++ b/hmcfgusb.h
@@ -32,6 +32,7 @@ struct hmcfgusb_dev {
 };
 
 int hmcfgusb_send(struct hmcfgusb_dev *usbdev, unsigned char* send_data, int len, int done);
+int hmcfgusb_send_null_frame(struct hmcfgusb_dev *usbdev);
 struct hmcfgusb_dev *hmcfgusb_init(hmcfgusb_cb_fn cb, void *data);
 int hmcfgusb_add_pfd(struct hmcfgusb_dev *dev, int fd, short events);
 int hmcfgusb_poll(struct hmcfgusb_dev *dev, int timeout);