Filter: use only single lower bit of filter return value

[lttng-ust.git] / liblttng-ust / lttng-filter-interpreter.c

diff --git a/liblttng-ust/lttng-filter-interpreter.c b/liblttng-ust/lttng-filter-interpreter.c
index e6e96dbff9a9bf53cdb346b68cd63a9b4728d457..690ebde9eece5e1dbb4695e067f014d895bf8a73 100644 (file)
--- a/liblttng-ust/lttng-filter-interpreter.c
+++ b/liblttng-ust/lttng-filter-interpreter.c
@@ -105,7 +105,7 @@ int stack_strcmp(struct estack *stack, int top, const char *cmp_type)
        return diff;
 }
 
-int lttng_filter_false(void *filter_data,
+uint64_t lttng_filter_false(void *filter_data,
                const char *filter_stack_data)
 {
        return 0;
@@ -157,7 +157,12 @@ LABEL_##name
 
 #endif
 
-int lttng_filter_interpret_bytecode(void *filter_data,
+/*
+ * Return 0 (discard), or raise the 0x1 flag (log event).
+ * Currently, other flags are kept for future extensions and have no
+ * effect.
+ */
+uint64_t lttng_filter_interpret_bytecode(void *filter_data,
                const char *filter_stack_data)
 {
        struct bytecode_runtime *bytecode = filter_data;
@@ -279,6 +284,7 @@ int lttng_filter_interpret_bytecode(void *filter_data,
                        goto end;
 
                OP(FILTER_OP_RETURN):
+                       /* LTTNG_FILTER_DISCARD  or LTTNG_FILTER_RECORD_FLAG */
                        retval = !!estack_ax_v;
                        ret = 0;
                        goto end;