postgres.git / summary / log / commit / refs

commit    c563d97c6bfd63e4d533bf01d0074d3a47e7a12c
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Thu Apr 28 15:50:58 2016 +0000

    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.


 src/include/postgres.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/include/postgres.h b/src/include/postgres.h
index 90cd3d55532..b34b93d8e4f 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


[parent: 0f54912837ec]