diff -r e8f354a25ac8 -r 68754c7de906 src/cx/json.h
--- a/src/cx/json.h	Thu Nov 07 20:22:56 2024 +0100
+++ b/src/cx/json.h	Thu Nov 07 22:46:58 2024 +0100
@@ -173,13 +173,14 @@
 
 // TODO: add support for CxAllocator
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 void cxJsonInit(CxJson *json);
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 void cxJsonDestroy(CxJson *json);
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
+cx_attr_access_r(2, 3)
 int cxJsonFilln(CxJson *json, const char *buf, size_t len);
 
 #define cxJsonFill(json, str) _Generic((str), \
@@ -189,7 +190,7 @@
     const char*: cx_json_fill_str)            \
     (json, str)
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline int cx_json_fill_cxstr(
         CxJson *json,
         cxstring str
@@ -197,7 +198,7 @@
     return cxJsonFilln(json, str.ptr, str.length);
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline int cx_json_fill_mutstr(
         CxJson *json,
         cxmutstr str
@@ -205,7 +206,8 @@
     return cxJsonFilln(json, str.ptr, str.length);
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
+cx_attr_cstr_arg(2)
 static inline int cx_json_fill_str(
         CxJson *json,
         const char *str
@@ -213,78 +215,79 @@
     return cxJsonFilln(json, str, strlen(str));
 }
 
+void cxJsonValueFree(CxJsonValue *value);
 
-__attribute__((__nonnull__))
+// TODO: if the CxJsonValue was a returned value, we could reference cxJsonValueFree() as deallocator
+cx_attr_nonnull
 int cxJsonNext(CxJson *json, CxJsonValue **value);
 
-void cxJsonValueFree(CxJsonValue *value);
-
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsObject(CxJsonValue *value) {
     return value->type == CX_JSON_OBJECT;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsArray(CxJsonValue *value) {
     return value->type == CX_JSON_ARRAY;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsString(CxJsonValue *value) {
     return value->type == CX_JSON_STRING;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsNumber(CxJsonValue *value) {
     return value->type == CX_JSON_NUMBER || value->type == CX_JSON_INTEGER;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsInteger(CxJsonValue *value) {
     return value->type == CX_JSON_INTEGER;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsLiteral(CxJsonValue *value) {
     return value->type == CX_JSON_LITERAL;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsBool(CxJsonValue *value) {
     return cxJsonIsLiteral(value) && value->value.literal != CX_JSON_NULL;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsTrue(CxJsonValue *value) {
     return cxJsonIsLiteral(value) && value->value.literal == CX_JSON_TRUE;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsFalse(CxJsonValue *value) {
     return cxJsonIsLiteral(value) && value->value.literal == CX_JSON_FALSE;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonIsNull(CxJsonValue *value) {
     return cxJsonIsLiteral(value) && value->value.literal == CX_JSON_NULL;
 }
 
-__attribute__((__nonnull__, __returns_nonnull__))
+cx_attr_nonnull
+cx_attr_returns_nonnull
 static inline char *cxJsonAsString(CxJsonValue *value) {
     return value->value.string.ptr;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline cxstring cxJsonAsCxString(CxJsonValue *value) {
     return cx_strcast(value->value.string);
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline cxmutstr cxJsonAsCxMutStr(CxJsonValue *value) {
     return value->value.string;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline double cxJsonAsDouble(CxJsonValue *value) {
     if (value->type == CX_JSON_INTEGER) {
         return (double) value->value.integer;
@@ -293,7 +296,7 @@
     }
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline int64_t cxJsonAsInteger(CxJsonValue *value) {
     if (value->type == CX_JSON_INTEGER) {
         return value->value.integer;
@@ -302,23 +305,26 @@
     }
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline bool cxJsonAsBool(CxJsonValue *value) {
     return value->value.literal == CX_JSON_TRUE;
 }
 
-__attribute__((__nonnull__))
+cx_attr_nonnull
 static inline size_t cxJsonArrSize(CxJsonValue *value) {
     return value->value.array.array_size;
 }
 
-__attribute__((__nonnull__, __returns_nonnull__))
+cx_attr_nonnull
+cx_attr_returns_nonnull
 CxJsonValue *cxJsonArrGet(CxJsonValue *value, size_t index);
 
 // TODO: add cxJsonArrIter()
 
 // TODO: implement cxJsonObjGet as a _Generic with support for cxstring
-__attribute__((__nonnull__, __returns_nonnull__))
+cx_attr_nonnull
+cx_attr_returns_nonnull
+cx_attr_cstr_arg(2)
 CxJsonValue *cxJsonObjGet(CxJsonValue *value, const char* name);
 
 #ifdef __cplusplus