From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 15 Nov 2011 22:03:15 +0000 (-0500)
Subject: Document LGPL TRACEPOINT_CREATE_PROBES restrictions
X-Git-Tag: v1.9.1~96
X-Git-Url: https://git.lttng.org/?a=commitdiff_plain;h=1909f468edb241b4dc84d8327efa3a3e3bc319da;p=lttng-ust.git

Document LGPL TRACEPOINT_CREATE_PROBES restrictions

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/include/lttng/tracepoint-event.h b/include/lttng/tracepoint-event.h
index e7ea461b..b47bf6a7 100644
--- a/include/lttng/tracepoint-event.h
+++ b/include/lttng/tracepoint-event.h
@@ -35,6 +35,19 @@
  *       #define TRACEPOINT_INCLUDE_PATH .
  *     combined with -Ipath_to_header as compiler argument to allow
  *     searching for a header within your project build tree.
+ *
+ * Note considering licensing:
+ *
+ * Including the tracepoint-event.h header without the
+ * TRACEPOINT_CREATE_PROBES macro defined is fine within any application
+ * source code, even for non-LGPL-compatible applications.
+ *
+ * However, TRACEPOINT_CREATE_PROBES should only be defined within
+ * LGPL-compatible C files. This means that the tracepoint probe object
+ * should be relinkable when distributed, either by providing it as a
+ * dynamically linkable shared object (.so library), or by providing the
+ * build scripts and object files required to relink the object if
+ * statically linked.
  */
 
 #ifdef __cplusplus
diff --git a/tests/demo/tp.c b/tests/demo/tp.c
index d3c7d536..9f774990 100644
--- a/tests/demo/tp.c
+++ b/tests/demo/tp.c
@@ -18,5 +18,9 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+/*
+ * Note: TRACEPOINT_CREATE_PROBES can only be defined within LGPL C
+ * files. See comment in lttng/tracepoint-event.h for detail.
+ */
 #define TRACEPOINT_CREATE_PROBES
 #include "ust_tests_demo.h"
diff --git a/tests/hello/tp.c b/tests/hello/tp.c
index 509f5a49..01adef16 100644
--- a/tests/hello/tp.c
+++ b/tests/hello/tp.c
@@ -18,5 +18,9 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+/*
+ * Note: TRACEPOINT_CREATE_PROBES can only be defined within LGPL C
+ * files. See comment in lttng/tracepoint-event.h for detail.
+ */
 #define TRACEPOINT_CREATE_PROBES
 #include "ust_tests_hello.h"