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commit    675ddc4d704f4cde0bc72244263a9efbb0d32cb8
Author:   Peter Eisentraut <peter@eisentraut.org>
Date:     Fri Sep 12 06:13:05 2025 +0000

    Improve pgbench definition of yyscan_t
    
    It was defining yyscan_t as a macro while the rest of the code uses a
    typedef with #ifdef guards around it.  The latter is also what the
    flex generated code uses.  So it seems best to make it look like those
    other places for consistency.
    
    The old way also had a potential for conflict if some code included
    multiple headers providing yyscan_t.  exprscan.l includes
    
        #include "fe_utils/psqlscan_int.h"
        #include "pgbench.h"
    
    and fe_utils/psqlscan_int.h contains
    
        #ifndef YY_TYPEDEF_YY_SCANNER_T
        #define YY_TYPEDEF_YY_SCANNER_T
        typedef void *yyscan_t;
        #endif
    
    which was then followed by pgbench.h
    
        #define yyscan_t  void *
    
    and then the generated code in exprscan.c
    
        #ifndef YY_TYPEDEF_YY_SCANNER_T
        #define YY_TYPEDEF_YY_SCANNER_T
        typedef void* yyscan_t;
        #endif
    
    This works, but if the #ifdef guard in psqlscan_int.h is removed, this
    fails.
    
    We want to move toward allowing repeat typedefs, per C11, but for that
    we need to make sure they are all the same.
    
    Reviewed-by: Chao Li <li.evan.chao@gmail.com>
    Discussion: https://www.postgresql.org/message-id/flat/10d32190-f31b-40a5-b177-11db55597355@eisentraut.org


 src/bin/pgbench/pgbench.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/bin/pgbench/pgbench.h b/src/bin/pgbench/pgbench.h
index e053c9e2eb6..f8b7b497d1e 100644
--- a/src/bin/pgbench/pgbench.h
+++ b/src/bin/pgbench/pgbench.h
@@ -16,11 +16,14 @@
 /*
  * This file is included outside exprscan.l, in places where we can't see
  * flex's definition of typedef yyscan_t.  Fortunately, it's documented as
- * being "void *", so we can use a macro to keep the function declarations
+ * being "void *", so we can use typedef to keep the function declarations
  * here looking like the definitions in exprscan.l.  exprparse.y and
  * pgbench.c also use this to be able to declare things as "yyscan_t".
  */
-#define yyscan_t  void *
+#ifndef YY_TYPEDEF_YY_SCANNER_T
+#define YY_TYPEDEF_YY_SCANNER_T
+typedef void *yyscan_t;
+#endif
 
 /*
  * Likewise, we can't see exprparse.y's definition of union YYSTYPE here,


[parent: 2aac62be8cbb]