From: Uwe Hermann <redacted>
Date: Sun, 21 Oct 2012 20:40:43 +0000 (+0200)
Subject: sr_init/sr_exit: Improve docs, add error checks.
X-Git-Tag: dsupstream~651
X-Git-Url: http://sigrok.org/gitweb/?p=libsigrok.git;a=commitdiff_plain;h=c46762a285d7c844a771f5c1f0ad2447a00906b3

sr_init/sr_exit: Improve docs, add error checks.
---

diff --git a/backend.c b/backend.c
index dd38f66e..eba03aaf 100644
--- a/backend.c
+++ b/backend.c
@@ -25,13 +25,27 @@
 /**
  * Initialize libsigrok.
  *
- * @return SR_OK upon success, a (negative) error code otherwise.
+ * This function must be called before any other libsigrok function.
+ *
+ * @param ctx Pointer to a libsigrok context struct pointer. Must not be NULL.
+ *            This will be a pointer to a newly allocated libsigrok context
+ *            object upon success, and is undefined upon errors.
+ *
+ * @return SR_OK upon success, a (negative) error code otherwise. Upon errors
+ *         the 'ctx' pointer is undefined and should not be used. Upon success,
+ *         the context will be free'd by sr_exit() as part of the libsigrok
+ *         shutdown.
  */
 SR_API int sr_init(struct sr_context **ctx)
 {
 	int ret = SR_ERR;
 	struct sr_context *context;
 
+	if (!ctx) {
+		sr_err("%s(): libsigrok context was NULL.", __func__);
+		return SR_ERR;
+	}
+
 	/* + 1 to handle when struct sr_context has no members. */
 	context = g_try_malloc0(sizeof(struct sr_context) + 1);
 
@@ -42,8 +56,8 @@ SR_API int sr_init(struct sr_context **ctx)
 
 #ifdef HAVE_LIBUSB_1_0
 	ret = libusb_init(&context->libusb_ctx);
-	if (LIBUSB_SUCCESS != ret) {
-		sr_err("libusb_init() returned %s\n", libusb_error_name(ret));
+	if (LIBUSB_SUCCESS == ret) {
+		sr_err("libusb_init() returned %s.\n", libusb_error_name(ret));
 		goto done;
 	}
 #endif
@@ -58,10 +72,17 @@ done:
 /**
  * Shutdown libsigrok.
  *
+ * @param ctx Pointer to a libsigrok context struct. Must not be NULL.
+ *
  * @return SR_OK upon success, a (negative) error code otherwise.
  */
 SR_API int sr_exit(struct sr_context *ctx)
 {
+	if (!ctx) {
+		sr_err("%s(): libsigrok context was NULL.", __func__);
+		return SR_ERR;
+	}
+
 	sr_hw_cleanup_all();
 
 #ifdef HAVE_LIBUSB_1_0