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authorTom Lane2016-04-28 15:50:58 +0000
committerTom Lane2016-04-28 15:51:26 +0000
commita6c6789c46843988f8eef4afc462311f41bd6e27 (patch)
tree6d0a9d51f7d8f55f2cdb2e0643f507d6307ca5d1
parentcbff4b7085d779759e0e287ec3534d3da9ce72ab (diff)
Adjust DatumGetBool macro, this time for sure.
Commit 23a41573c attempted to fix the DatumGetBool macro to ignore bits in a Datum that are to the left of the actual bool value. But it did that by casting the Datum to bool; and on compilers that use C99 semantics for bool, that ends up being a whole-word test, not a 1-byte test. This seems to be the true explanation for contrib/seg failing in VS2015. To fix, use GET_1_BYTE() explicitly. I think in the previous patch, I'd had some idea of not having to commit to bool being exactly 1 byte wide, but regardless of what the compiler's bool is, boolean columns and Datums are certainly 1 byte wide. The previous fix was (eventually) back-patched into all active versions, so do likewise with this one.
-rw-r--r--src/include/postgres.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/src/include/postgres.h b/src/include/postgres.h
index d14440951e4..7de7ff2fad2 100644
--- a/src/include/postgres.h
+++ b/src/include/postgres.h
@@ -326,7 +326,7 @@ typedef Datum *DatumPtr;
* the left of the width of bool, per comment above.
*/
-#define DatumGetBool(X) ((bool) (((bool) (X)) != 0))
+#define DatumGetBool(X) ((bool) (GET_1_BYTE(X) != 0))
/*
* BoolGetDatum