X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=backend.c;h=4823044efce580dbc9d7a116f1eb46e63a84a389;hb=e90cf076aa6854ad3f312179a121bafc4c6e9a22;hp=c94483f96be3d3e0ddfda4f17a28d3ae7d0a6e9b;hpb=b8072700c1bc7d13ba004fd897668b56cec4ac62;p=libsigrok.git

diff --git a/backend.c b/backend.c
index c94483f9..4823044e 100644
--- a/backend.c
+++ b/backend.c
@@ -19,19 +19,125 @@
  */
 
 #include <glib.h>
+#include "config.h" /* Needed for HAVE_LIBUSB_1_0 and others. */
 #include "libsigrok.h"
 #include "libsigrok-internal.h"
 
+/**
+ * @mainpage libsigrok API
+ *
+ * @section sec_intro Introduction
+ *
+ * The <a href="http://sigrok.org">sigrok</a> project aims at creating a
+ * portable, cross-platform, Free/Libre/Open-Source signal analysis software
+ * suite that supports various device types (such as logic analyzers,
+ * oscilloscopes, multimeters, and more).
+ *
+ * <a href="http://sigrok.org/wiki/Libsigrok">libsigrok</a> is a shared
+ * library written in C which provides the basic API for talking to
+ * <a href="http://sigrok.org/wiki/Supported_hardware">supported hardware</a>
+ * and reading/writing the acquired data into various
+ * <a href="http://sigrok.org/wiki/Input_output_formats">input/output
+ * file formats</a>.
+ *
+ * @section sec_api API reference
+ *
+ * See the "Modules" page for an introduction to various libsigrok
+ * related topics and the detailed API documentation of the respective
+ * functions.
+ *
+ * You can also browse the API documentation by file, or review all
+ * data structures.
+ *
+ * @section sec_mailinglists Mailing lists
+ *
+ * There are two mailing lists for sigrok/libsigrok: <a href="https://lists.sourceforge.net/lists/listinfo/sigrok-devel">sigrok-devel</a> and <a href="https://lists.sourceforge.net/lists/listinfo/sigrok-commits">sigrok-commits</a>.
+ *
+ * @section sec_irc IRC
+ *
+ * You can find the sigrok developers in the
+ * <a href="irc://chat.freenode.net/sigrok">\#sigrok</a>
+ * IRC channel on Freenode.
+ *
+ * @section sec_website Website
+ *
+ * <a href="http://sigrok.org/wiki/Libsigrok">sigrok.org/wiki/Libsigrok</a>
+ */
+
+/**
+ * @file
+ *
+ * Initializing and shutting down libsigrok.
+ */
+
+/**
+ * @defgroup grp_init Initialization
+ *
+ * Initializing and shutting down libsigrok.
+ *
+ * Before using any of the libsigrok functionality, sr_init() must
+ * be called to initialize the library, which will return a struct sr_context
+ * when the initialization was successful.
+ *
+ * When libsigrok functionality is no longer needed, sr_exit() should be
+ * called, which will (among other things) free the struct sr_context.
+ *
+ * Example for a minimal program using libsigrok:
+ *
+ * @code{.c}
+ *   #include <stdio.h>
+ *   #include <libsigrok/libsigrok.h>
+ *
+ *   int main(int argc, char **argv)
+ *   {
+ *   	int ret;
+ *   	struct sr_context *sr_ctx;
+ *
+ *   	if ((ret = sr_init(&sr_ctx)) != SR_OK) {
+ *   		printf("Error initializing libsigrok (%s): %s.",
+ *   		       sr_strerror_name(ret), sr_strerror(ret));
+ *   		return 1;
+ *   	}
+ *
+ *   	// Use libsigrok functions here...
+ *
+ *   	if ((ret = sr_exit(sr_ctx)) != SR_OK) {
+ *   		printf("Error shutting down libsigrok (%s): %s.",
+ *   		       sr_strerror_name(ret), sr_strerror(ret));
+ *   		return 1;
+ *   	}
+ *
+ *   	return 0;
+ *   }
+ * @endcode
+ *
+ * @{
+ */
+
 /**
  * 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);
 
@@ -40,6 +146,14 @@ SR_API int sr_init(struct sr_context **ctx)
 		goto done;
 	}
 
+#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));
+		goto done;
+	}
+#endif
+
 	*ctx = context;
 	ret = SR_OK;
 
@@ -50,13 +164,26 @@ 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
+	libusb_exit(ctx->libusb_ctx);
+#endif
+
 	g_free(ctx);
 
 	return SR_OK;
 }
+
+/** @} */