examples: add simple callbacl example

examples/Makefile.am

@@ -571,6 +571,19 @@ spmv_dw_block_spmv_SOURCES =			\
 	spmv/matrix_market/mmio.c
 endif
 
+####################
+# Callback example #
+####################
+
+check_PROGRAMS +=				\
+	callback/callback
+
+examplebin_PROGRAMS +=				\
+	callback/callback
+
+callback_callback_SOURCES =	\
+	callback/callback.c
+
 #######################
 # Incrementer example #
 #######################

examples/callback/callback.c

@@ -0,0 +1,70 @@
+/* StarPU --- Runtime system for heterogeneous multicore architectures.
+ *
+ * Copyright (C) 2009, 2010  Université de Bordeaux 1
+ * Copyright (C) 2010, 2011  Centre National de la Recherche Scientifique
+ *
+ * StarPU is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at
+ * your option) any later version.
+ *
+ * StarPU is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * See the GNU Lesser General Public License in COPYING.LGPL for more details.
+ */
+
+#include <starpu.h>
+#include <pthread.h>
+#include <sys/time.h>
+
+starpu_data_handle handle;
+
+void cpu_codelet(void *descr[], __attribute__ ((unused)) void *_args)
+{
+	int *val = (int *)STARPU_VARIABLE_GET_PTR(descr[0]);
+
+	*val += 1;
+}
+
+starpu_codelet cl =
+{
+	.where = STARPU_CPU,
+	.cpu_func = cpu_codelet,
+	.nbuffers = 1
+};
+
+void callback_func(void *callback_arg)
+{
+	struct starpu_task *task = starpu_task_create();
+	task->cl = &cl;
+	task->buffers[0].handle = handle;
+	task->buffers[0].mode = STARPU_RW;
+	starpu_task_submit(task);
+}
+
+int main(int argc, char **argv)
+{
+	int v=40;
+
+	starpu_init(NULL);
+	starpu_variable_data_register(&handle, 0, (uintptr_t)&v, sizeof(int));
+
+	struct starpu_task *task = starpu_task_create();
+	task->cl = &cl;
+	task->callback_func = callback_func;
+	task->callback_arg = NULL;
+	task->buffers[0].handle = handle;
+	task->buffers[0].mode = STARPU_RW;
+
+	starpu_task_submit(task);
+
+	starpu_task_wait_for_all();
+
+	fprintf(stderr, "v -> %d\n", v);
+
+	starpu_shutdown();
+
+	return 0;
+}