diff --git a/include/pocketpy/common/sstream.h b/include/pocketpy/common/sstream.h
index b1e37cd0..b1f5e75d 100644
--- a/include/pocketpy/common/sstream.h
+++ b/include/pocketpy/common/sstream.h
@@ -18,7 +18,7 @@ typedef struct pkpy_AnyStr {
     int type;
     union {
         int _int;
-        int64_t _int64;
+        int64_t _i64;
         float _float;
         double _double;
         char _char;
@@ -30,7 +30,7 @@ typedef struct pkpy_AnyStr {
 } pkpy_AnyStr;
 
 inline pkpy_AnyStr pkpy_AnyStr__int(int x) { return (pkpy_AnyStr){.type = 1, ._int = x}; }
-inline pkpy_AnyStr pkpy_AnyStr__int64(int64_t x) { return (pkpy_AnyStr){.type = 2, ._int64 = x}; }
+inline pkpy_AnyStr pkpy_AnyStr__i64(int64_t x) { return (pkpy_AnyStr){.type = 2, ._i64 = x}; }
 inline pkpy_AnyStr pkpy_AnyStr__float(float x) { return (pkpy_AnyStr){.type = 3, ._float = x}; }
 inline pkpy_AnyStr pkpy_AnyStr__double(double x) { return (pkpy_AnyStr){.type = 4, ._double = x}; }
 inline pkpy_AnyStr pkpy_AnyStr__char(char x) { return (pkpy_AnyStr){.type = 5, ._char = x}; }
@@ -43,7 +43,7 @@ void pkpy_SStream__ctor(pkpy_SStream* self);
 void pkpy_SStream__dtor(pkpy_SStream* self);
 
 void pkpy_SStream__write_int(pkpy_SStream* self, int);
-void pkpy_SStream__write_int64(pkpy_SStream* self, int64_t);
+void pkpy_SStream__write_i64(pkpy_SStream* self, int64_t);
 void pkpy_SStream__write_float(pkpy_SStream* self, float, int precision);
 void pkpy_SStream__write_double(pkpy_SStream* self, double, int precision);
 void pkpy_SStream__write_char(pkpy_SStream* self, char);
@@ -60,7 +60,7 @@ pkpy_Str pkpy_SStream__submit(pkpy_SStream* self);
 
 #define pkpy__anystr(x) _Generic((x), \
     int: pkpy_AnyStr__int, \
-    int64_t: pkpy_AnyStr__int64, \
+    int64_t: pkpy_AnyStr__i64, \
     float: pkpy_AnyStr__float, \
     double: pkpy_AnyStr__double, \
     char: pkpy_AnyStr__char, \
diff --git a/include/pocketpy/common/str.hpp b/include/pocketpy/common/str.hpp
index 6bec4580..ed690ff3 100644
--- a/include/pocketpy/common/str.hpp
+++ b/include/pocketpy/common/str.hpp
@@ -316,12 +316,12 @@ struct SStream: pkpy_SStream {
 
     SStream& operator<< (size_t val){
         // size_t could overflow int64, but nevermind...
-        pkpy_SStream__write_int64(this, val);
+        pkpy_SStream__write_i64(this, val);
         return *this;
     }
 
     SStream& operator<< (i64 val){
-        pkpy_SStream__write_int64(this, val);
+        pkpy_SStream__write_i64(this, val);
         return *this;
     }
 
diff --git a/src/common/sstream.c b/src/common/sstream.c
index d4ad9699..ad99a93a 100644
--- a/src/common/sstream.c
+++ b/src/common/sstream.c
@@ -24,7 +24,7 @@ void pkpy_SStream__write_int(pkpy_SStream* self, int i) {
     pkpy_SStream__write_cstr(self, buf);
 }
 
-void pkpy_SStream__write_int64(pkpy_SStream* self, int64_t i) {
+void pkpy_SStream__write_i64(pkpy_SStream* self, int64_t i) {
     char buf[23]; // sign + 21 digits + null terminator
     snprintf(buf, sizeof(buf), "%lld", i);
     pkpy_SStream__write_cstr(self, buf);
@@ -110,7 +110,7 @@ void pkpy_SStream__write_any(pkpy_SStream* self, const char* fmt, const pkpy_Any
             assert(i < n);
             switch(args[i].type){
                 case 1: pkpy_SStream__write_int(self, args[i]._int); break;
-                case 2: pkpy_SStream__write_int64(self, args[i]._int64); break;
+                case 2: pkpy_SStream__write_i64(self, args[i]._i64); break;
                 case 3: pkpy_SStream__write_float(self, args[i]._float, -1); break;
                 case 4: pkpy_SStream__write_double(self, args[i]._double, -1); break;
                 case 5: pkpy_SStream__write_char(self, args[i]._char); break;