diff options
Diffstat (limited to 'src/include/nodes/nodes.h')
| -rw-r--r-- | src/include/nodes/nodes.h | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h index b9e00bfddea..78dd917ecfa 100644 --- a/src/include/nodes/nodes.h +++ b/src/include/nodes/nodes.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.209 2008/08/22 00:16:04 tgl Exp $ + * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.210 2008/08/29 22:49:07 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -384,6 +384,23 @@ typedef struct Node * !WARNING!: Avoid using newNode directly. You should be using the * macro makeNode. eg. to create a Query node, use makeNode(Query) * + * Note: the size argument should always be a compile-time constant, so the + * apparent risk of multiple evaluation doesn't matter in practice. + */ +#ifdef __GNUC__ + +/* With GCC, we can use a compound statement within an expression */ +#define newNode(size, tag) \ +({ Node *_result; \ + AssertMacro((size) >= sizeof(Node)); /* need the tag, at least */ \ + _result = (Node *) palloc0fast(size); \ + _result->type = (tag); \ + _result; \ +}) + +#else + +/* * There is no way to dereference the palloc'ed pointer to assign the * tag, and also return the pointer itself, so we need a holder variable. * Fortunately, this macro isn't recursive so we just define @@ -399,6 +416,8 @@ extern PGDLLIMPORT Node *newNodeMacroHolder; newNodeMacroHolder \ ) +#endif /* __GNUC__ */ + #define makeNode(_type_) ((_type_ *) newNode(sizeof(_type_),T_##_type_)) #define NodeSetTag(nodeptr,t) (((Node*)(nodeptr))->type = (t)) |