sumtype: detect compilers with extensions off

mcha-forks · Jan 2, 2025 · 3fec49b · 3fec49b
1 parent c8319f5
commit 3fec49b
Showing 1 changed file with 12 additions and 1 deletion.
diff --git a/include/stc/sys/sumtype.h b/include/stc/sys/sumtype.h
@@ -106,7 +106,17 @@ int main(void) {
         c_EVAL(c_LOOP(_c_vartuple_var, T, __VA_ARGS__, (0),)) \
     }
 
-#if defined __GNUC__ || defined __clang__ || defined __TINYC__ || _MSC_VER >= 1939
+#ifdef __clang__
+#if !__is_identifier(__typeof__)
+#define __STC_HAS_TYPEOF
+#endif
+#elif (defined(__GNUC__) && __has_builtin(__typeof__))  \
+    || defined(__TINYC__)                               \
+    || _MSC_FULL_VER >= 193933428
+#define __STC__STC_HAS_TYPEOF
+#endif
+
+#ifdef __STC_HAS_TYPEOF
     #define c_when(var) \
         for (__typeof__(var) _match = (var); _match; _match = NULL) \
         switch (_match->_any_.tag)
@@ -119,6 +129,7 @@ int main(void) {
         for (__typeof__(v) _var = (v); _var; _var = NULL) \
             if (c_holds(_var, Tag)) \
                 for (__typeof__(_var->Tag.var) *x = &_var->Tag.var; x; x = NULL)
+    #undef __STC_HAS_TYPEOF
 #else
     typedef union { struct { uint8_t tag; } _any_; } _c_any_variant;
     #define c_when(var) \