trace: Document function pattern prefixes

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>

diff --git a/src/utils/os_unix.c b/src/utils/os_unix.c
index 39f00943b705260df5bb90ade81c75ca34229b67..0935482569404465212961d914c0176d00c5c651 100644 (file)
--- a/src/utils/os_unix.c
+++ b/src/utils/os_unix.c
@@ -570,6 +570,11 @@ int testing_test_fail(bool is_alloc)
 
        pos = wpa_trace_fail_func[is_alloc];
 
+       /* The prefixes mean:
+        * - '=': The function needs to be next in the backtrace
+        * - '?': The function is optionally present in the backtrace
+        */
+
        match = 0;
        while (i < res) {
                int allow_skip = 1;