Silence MSVC warnings about redefinition of isnan

adunstan · adunstan · commit d5d7f7f3b78e · 2018-11-18T12:36:31.000-05:00
Some versions of perl.h define isnan when the compiler is MSVC. To avoid warnings about this, undefine the symbol before including perl.h and re-add the definition afterwards if it wasn't recreated. Discussion: https://postgr.es/m/caf0568e-3c1f-07fd-6914-d903f22560f2@2ndQuadrant.com
diff --git a/src/pl/plperl/plperl.h b/src/pl/plperl/plperl.h
@@ -40,10 +40,15 @@
 
 /*
  * ActivePerl 5.18 and later are MinGW-built, and their headers use GCC's
- * __inline__.  Translate to something MSVC recognizes.
+ * __inline__.  Translate to something MSVC recognizes. Also, perl.h sometimes
+ * defines isnan, so undefine it here and put back the definition later if
+ * perl.h doesn't.
  */
 #ifdef _MSC_VER
 #define __inline__ inline
+#ifdef isname
+#undef isnan
+#endif
 #endif
 
 /*
@@ -135,6 +140,13 @@
 #define vprintf			pg_vprintf
 #define printf(...)		pg_printf(__VA_ARGS__)
 
+/* put back the definition of isnan if needed */
+#ifdef _MSC_VER
+#ifndef isnan
+#define isnan(x) _isnan(x)
+#endif
+#endif
+
 /* perl version and platform portability */
 #define NEED_eval_pv
 #define NEED_newRV_noinc
