diff --git a/lib/include/picrin.h b/lib/include/picrin.h
index ed71ece1..5b2cbb6b 100644
--- a/lib/include/picrin.h
+++ b/lib/include/picrin.h
@@ -41,7 +41,7 @@ typedef struct value {
   uint64_t v;
 #else
   union {
-    void *data;
+    void *p;
     double f;
     int i;
     char c;
diff --git a/lib/state.c b/lib/state.c
index 76406f82..947854a1 100644
--- a/lib/state.c
+++ b/lib/state.c
@@ -52,7 +52,6 @@ pic_init_core(pic_state *pic)
 
   pic_init_bool(pic); DONE;
   pic_init_pair(pic); DONE;
-  pic_init_port(pic); DONE;
   pic_init_number(pic); DONE;
   pic_init_proc(pic); DONE;
   pic_init_symbol(pic); DONE;
@@ -69,6 +68,9 @@ pic_init_core(pic_state *pic)
 #if PIC_USE_CONT
   pic_init_cont(pic); DONE;
 #endif
+#if PIC_USE_PORT
+  pic_init_port(pic); DONE;
+#endif
 #if PIC_USE_READ
   pic_init_read(pic); DONE;
 #endif
@@ -161,9 +163,6 @@ pic_open(pic_allocf allocf, void *userdata, pic_panicf panicf)
     pic->halt = obj_value(pic, proc);
   }
 
-  /* panic handler */
-  pic->panicf = NULL;
-
   /* turn on GC */
   pic->gc_enable = true;
 
diff --git a/lib/string.c b/lib/string.c
index 492b200a..cbc8f84b 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -273,12 +273,12 @@ pic_vstrf_value(pic_state *pic, const char *fmt, va_list ap)
   }
   case 'p': {
     static const char digits[] = "0123456789abcdef";
-    static const size_t bufsiz = sizeof(long) * CHAR_BIT / 4;
+#define MAXLEN (sizeof(long) * CHAR_BIT / 4)
     unsigned long vp = (unsigned long) va_arg(ap, void*);
-    char buf[2 + bufsiz + 1] = "0x", *p = buf + 2;
+    char buf[2 + MAXLEN + 1] = "0x", *p = buf + 2;
     size_t i;
-    for (i = 0; i < bufsiz; ++i) {
-      p[bufsiz - i - 2] = digits[vp % 16];
+    for (i = 0; i < MAXLEN; ++i) {
+      p[MAXLEN - i - 2] = digits[vp % 16];
       vp /= 16;
     }
     p[i] = '\0';
diff --git a/lib/value.h b/lib/value.h
index 14b6dd36..e744b9d0 100644
--- a/lib/value.h
+++ b/lib/value.h
@@ -42,7 +42,7 @@ enum {
 PIC_STATIC_INLINE void
 make_value(struct value *v, int type)
 {
-  static const struct value zero = { 0 };
+  static const struct value zero = { {0}, 0 };
   *v = zero;
   v->type = type;
 }
@@ -61,7 +61,7 @@ make_float_value(struct value *v, double f)
   v->u.f = f;
 }
 
-PIC_STATIC_INLINE struct value
+PIC_STATIC_INLINE void
 make_char_value(struct value *v, char c)
 {
   make_value(v, PIC_TYPE_CHAR);