--- src/rlang/c-utils.h	2026-04-07 16:05:47.000000000 +0800
+++ src/rlang/c-utils.h	2026-07-06 06:11:10.000000000 +0800
@@ -9,6 +9,12 @@
 #include <math.h>
 #include <float.h>
 #include <string.h>
+
+#ifdef __cplusplus
+#include <cmath>
+using std::isfinite;
+#endif
+
 #include "cnd.h"
 
 #define R_ARR_SIZEOF(X) sizeof(X) / sizeof(X[0])