From 2999345d8f501d54dc19bc3f60f01c573910d565 Mon Sep 17 00:00:00 2001
From: Michael Gernoth <michael@gernoth.net>
Date: Mon, 7 Jun 2010 09:59:21 +0200
Subject: [PATCH] add struct for usbtmc header

---
 scope.c  |  6 ++++--
 usbtmc.c |  3 +--
 usbtmc.h | 19 +++++++++++++++++++
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/scope.c b/scope.c
index 3152243..806ba34 100644
--- a/scope.c
+++ b/scope.c
@@ -36,8 +36,10 @@ struct scope* initscope(void)
 
 	usbdev = usbtmc_initscope();
 
-	if (!usbdev)
-		return NULL;
+	if (!usbdev) {
+		printf("No scope found.\n");
+		exit(EXIT_FAILURE);
+	}
 
 	sc = calloc(1, sizeof(struct scope));
 	if (sc == NULL) {
diff --git a/usbtmc.c b/usbtmc.c
index 622ea80..32f83a8 100644
--- a/usbtmc.c
+++ b/usbtmc.c
@@ -126,8 +126,7 @@ usb_dev_handle* usbtmc_initscope(void) {
 	//Locate and open the scope
 	dev = usbtmc_find_scope();
 	if (!dev) {
-		printf("No scope found.\n");
-		exit(1);
+		return NULL;
 	}
 	usbtmc_claim(dev);
 	//The following code isn't really necessary, the program works
diff --git a/usbtmc.h b/usbtmc.h
index 1ac3005..bae36da 100644
--- a/usbtmc.h
+++ b/usbtmc.h
@@ -1,3 +1,22 @@
+struct usbtmc_header {
+	unsigned char MsgID;
+	unsigned char bTag;
+	unsigned char bTagInverse;
+	unsigned char Reserved3;
+	uint32_t TransferSize;
+	unsigned char bmTransferAttributes;
+	unsigned char TermChar; /* Only in REQUEST_DEV_DEP_MSG_IN */
+	unsigned char Reverved10;
+	unsigned char Reverved11;
+} __attribute__ ((__packed__));
+
+#define USBTMC_DEV_DEP_MSG_OUT		0x1
+#define USBTMC_REQUEST_DEV_DEP_MSG_IN	0x2
+#define USBTMC_DEV_DEP_MSG_IN		0x2
+
+#define USBTMC_TRANSFERATTRIB_EOM	(1<<0)
+#define USBTMC_TRANSFERATTRIB_TERMCHAR	(1<<1)
+
 int usbtmc_sendscpi(struct usb_dev_handle *dev, char* cmd, unsigned char *resp, int resplen);
 struct usb_dev_handle* usbtmc_initscope(void);
 void usbtmc_close(struct usb_dev_handle *sc);
-- 
2.39.2