feat: implement va_*() functions

1 files changed, 31 insertions, 0 deletions

diff --git a/std.h b/std.h
index 23a2e9a..86c86f5 100644
--- a/std.h
+++ b/std.h
@@ -29,3 +29,34 @@ int strncmp(const char*, const char*, size_t);
 char* strstr(const char*, const char*);
 
 #define NULL 0
+
+#ifdef __ducc__
+
+// System V Application Binary Interface
+// AMD64 Architecture Processor Supplement
+// (With LP64 and ILP32 Programming Models)
+// Version 1.0
+// Figure 3.34: va_list Type Declaration
+struct __va_list__ {
+    // unsigned int gp_offset;
+    // unsigned int fp_offset;
+    int gp_offset;
+    int fp_offset;
+    void* overflow_arg_area;
+    void* reg_save_area;
+};
+// ducc currently does not support array type.
+// typedef struct __va_list__ va_list[1];
+typedef struct __va_list__* va_list;
+
+// va_start() is currently implemented as a special form due to the limitation of #define macro.
+void va_end(va_list args) {
+}
+
+#else
+
+#include <stdarg.h>
+
+#endif
+
+int vfprintf(FILE*, const char*, va_list);