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authorThomas Munro2022-12-22 04:14:23 +0000
committerThomas Munro2022-12-22 05:32:10 +0000
commit3f28bd7337d7c01820283fee51027a9dc9d2295f (patch)
tree504103a001fac55d82ea258352c1e9c5490f08fc
parent01be9d498fa4b836ec3dbf035b6743c8b8f34767 (diff)
Add work-around for VA_ARGS_NARGS() on MSVC.
The previous coding of VA_ARGS_NARGS() always returned 1 on Visual Studio, because it treats __VA_ARGS__ as a single token unless you jump through extra hoops. Newer compilers have an option to fix that. Add a comment about that so that we can remember to clean this up in the future when our minimum MSVC version advances. Author: Victor Spirin <[email protected]> Reviewed-by: Thomas Munro <[email protected]> Reviewed-by: Tom Lane <[email protected]> Reviewed-by: Michael Paquier <[email protected]> Discussion: https://postgr.es/m/f450fc57-a147-19d0-e50c-33571c52cc13%40postgrespro.ru
-rw-r--r--src/include/c.h20
1 files changed, 20 insertions, 0 deletions
diff --git a/src/include/c.h b/src/include/c.h
index bd6d8e5bf5..7567ef7888 100644
--- a/src/include/c.h
+++ b/src/include/c.h
@@ -324,7 +324,25 @@
* pretty trivial: VA_ARGS_NARGS_() returns its 64th argument, and we set up
* the call so that that is the appropriate one of the list of constants.
* This idea is due to Laurent Deniau.
+ *
+ * MSVC has an implementation of __VA_ARGS__ that doesn't conform to the
+ * standard unless you use the /Zc:preprocessor compiler flag, but that
+ * isn't available before Visual Studio 2019. For now, use a different
+ * definition that also works on older compilers.
*/
+#ifdef _MSC_VER
+#define EXPAND(args) args
+#define VA_ARGS_NARGS(...) \
+ VA_ARGS_NARGS_ EXPAND((__VA_ARGS__, \
+ 63,62,61,60, \
+ 59,58,57,56,55,54,53,52,51,50, \
+ 49,48,47,46,45,44,43,42,41,40, \
+ 39,38,37,36,35,34,33,32,31,30, \
+ 29,28,27,26,25,24,23,22,21,20, \
+ 19,18,17,16,15,14,13,12,11,10, \
+ 9, 8, 7, 6, 5, 4, 3, 2, 1, 0))
+#else
+
#define VA_ARGS_NARGS(...) \
VA_ARGS_NARGS_(__VA_ARGS__, \
63,62,61,60, \
@@ -334,6 +352,8 @@
29,28,27,26,25,24,23,22,21,20, \
19,18,17,16,15,14,13,12,11,10, \
9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+#endif
+
#define VA_ARGS_NARGS_( \
_01,_02,_03,_04,_05,_06,_07,_08,_09,_10, \
_11,_12,_13,_14,_15,_16,_17,_18,_19,_20, \