diff -r 53e22f112b11 -r 15b3ca7ee33f src/cx/json.h
--- a/src/cx/json.h	Tue Nov 12 17:34:04 2024 +0100
+++ b/src/cx/json.h	Mon Nov 18 22:05:42 2024 +0100
@@ -183,6 +183,36 @@
 cx_attr_access_r(2, 3)
 int cxJsonFilln(CxJson *json, const char *buf, size_t len);
 
+#ifdef __cplusplus
+} // extern "C"
+
+cx_attr_nonnull
+static inline int cxJsonFill(
+        CxJson *json,
+        cxstring str
+) {
+    return cxJsonFilln(json, str.ptr, str.length);
+}
+
+cx_attr_nonnull
+static inline int cxJsonFill(
+        CxJson *json,
+        cxmutstr str
+) {
+    return cxJsonFilln(json, str.ptr, str.length);
+}
+
+cx_attr_nonnull
+cx_attr_cstr_arg(2)
+static inline int cxJsonFill(
+        CxJson *json,
+        const char *str
+) {
+    return cxJsonFilln(json, str, strlen(str));
+}
+
+extern "C" {
+#else // __cplusplus
 #define cxJsonFill(json, str) _Generic((str), \
     cxstring: cx_json_fill_cxstr,             \
     cxmutstr: cx_json_fill_mutstr,            \
@@ -214,6 +244,7 @@
 ) {
     return cxJsonFilln(json, str, strlen(str));
 }
+#endif
 
 void cxJsonValueFree(CxJsonValue *value);