optional: Add LTTNG_OPTIONAL_INIT_VALUE

[lttng-tools.git] / src / common / optional.h

diff --git a/src/common/optional.h b/src/common/optional.h
index 05f6054dade7c0a8fecbf20b5ef0bb5de1023807..ca7d1f043d21bdef1b9ad8dc716452ee49fe7858 100644 (file)
--- a/src/common/optional.h
+++ b/src/common/optional.h
@@ -62,18 +62,34 @@
  * wrapped optional types. It is meant to be used with PODs.
  */
 #define LTTNG_OPTIONAL_GET(optional)                   \
  * wrapped optional types. It is meant to be used with PODs.
  */
 #define LTTNG_OPTIONAL_GET(optional)                   \

-        ({                                             \
+       ({                                              \

                assert((optional).is_set);              \
                (optional).value;                       \
        })
 
 /*
                assert((optional).is_set);              \
                (optional).value;                       \
        })
 
 /*

- * Initialize an optional field.
+ * This macro is available as a 'convenience' to allow sites that assume
+ * an optional value is set to assert() that it is set when fecthing the
+ * underlying value's address.
+ */
+#define LTTNG_OPTIONAL_GET_PTR(optional)                       \
+       ({                                              \
+               assert((optional).is_set);              \
+               &(optional).value;                      \
+       })
+
+/*
+ * Initialize an optional field as unset.

  *
  * The wrapped field is set to the value it would gave if it had static storage
  * duration.
  */
  *
  * The wrapped field is set to the value it would gave if it had static storage
  * duration.
  */

-#define LTTNG_OPTIONAL_INIT { .is_set = 0 }
+#define LTTNG_OPTIONAL_INIT_UNSET { .is_set = 0 }
+
+/*
+ * Initialize an optional field as 'set' with a given value.
+ */
+#define LTTNG_OPTIONAL_INIT_VALUE(val) { .value = val, .is_set = 1 }

 
 /* Set the value of an optional field. */
 #define LTTNG_OPTIONAL_SET(field_ptr, val)     \
 
 /* Set the value of an optional field. */
 #define LTTNG_OPTIONAL_SET(field_ptr, val)     \