diff --git a/src/codegen.c b/src/codegen.c
index 356fba0d..74d5f8d8 100644
--- a/src/codegen.c
+++ b/src/codegen.c
@@ -1495,114 +1495,116 @@ pic_set(pic_state *pic, const char *name, pic_value value)
 void
 print_code(pic_state *pic, struct pic_code c)
 {
-    printf("[%2d] ", c.insn);
-    switch (c.insn) {
-    case OP_POP:
-      puts("OP_POP");
-      break;
-    case OP_PUSHNIL:
-      puts("OP_PUSHNIL");
-      break;
-    case OP_PUSHTRUE:
-      puts("OP_PUSHTRUE");
-      break;
-    case OP_PUSHFALSE:
-      puts("OP_PUSHFALSE");
-      break;
-    case OP_PUSHFLOAT:
-      printf("OP_PUSHFLOAT\t%f\n", c.u.f);
-      break;
-    case OP_PUSHINT:
-      printf("OP_PUSHINT\t%d\n", c.u.i);
-      break;
-    case OP_PUSHCHAR:
-      printf("OP_PUSHCHAR\t%c\n", c.u.c);
-      break;
-    case OP_PUSHCONST:
-      printf("OP_PUSHCONST\t%d\n", c.u.i);
-      break;
-    case OP_GREF:
-      printf("OP_GREF\t%i\n", c.u.i);
-      break;
-    case OP_GSET:
-      printf("OP_GSET\t%i\n", c.u.i);
-      break;
-    case OP_LREF:
-      printf("OP_LREF\t%d\n", c.u.i);
-      break;
-    case OP_LSET:
-      printf("OP_LSET\t%d\n", c.u.i);
-      break;
-    case OP_CREF:
-      printf("OP_CREF\t%d\t%d\n", c.u.r.depth, c.u.r.idx);
-      break;
-    case OP_CSET:
-      printf("OP_CSET\t%d\t%d\n", c.u.r.depth, c.u.r.idx);
-      break;
-    case OP_JMP:
-      printf("OP_JMP\t%d\n", c.u.i);
-      break;
-    case OP_JMPIF:
-      printf("OP_JMPIF\t%d\n", c.u.i);
-      break;
-    case OP_CALL:
-      printf("OP_CALL\t%d\n", c.u.i);
-      break;
-    case OP_TAILCALL:
-      printf("OP_TAILCALL\t%d\n", c.u.i);
-      break;
-    case OP_RET:
-      puts("OP_RET");
-      break;
-    case OP_LAMBDA:
-      printf("OP_LAMBDA\t%d\n", c.u.i);
-      break;
-    case OP_CONS:
-      puts("OP_CONS");
-      break;
-    case OP_CAR:
-      puts("OP_CAR");
-      break;
-    case OP_NILP:
-      puts("OP_NILP");
-      break;
-    case OP_CDR:
-      puts("OP_CDR");
-      break;
-    case OP_ADD:
-      puts("OP_ADD");
-      break;
-    case OP_SUB:
-      puts("OP_SUB");
-      break;
-    case OP_MUL:
-      puts("OP_MUL");
-      break;
-    case OP_DIV:
-      puts("OP_DIV");
-      break;
-    case OP_MINUS:
-      puts("OP_MINUS");
-      break;
-    case OP_EQ:
-      puts("OP_EQ");
-      break;
-    case OP_LT:
-      puts("OP_LT");
-      break;
-    case OP_LE:
-      puts("OP_LE");
-      break;
-    case OP_STOP:
-      puts("OP_STOP");
-      break;
-    }
+  UNUSED(pic);
+
+  printf("[%2d] ", c.insn);
+  switch (c.insn) {
+  case OP_POP:
+    puts("OP_POP");
+    break;
+  case OP_PUSHNIL:
+    puts("OP_PUSHNIL");
+    break;
+  case OP_PUSHTRUE:
+    puts("OP_PUSHTRUE");
+    break;
+  case OP_PUSHFALSE:
+    puts("OP_PUSHFALSE");
+    break;
+  case OP_PUSHFLOAT:
+    printf("OP_PUSHFLOAT\t%f\n", c.u.f);
+    break;
+  case OP_PUSHINT:
+    printf("OP_PUSHINT\t%d\n", c.u.i);
+    break;
+  case OP_PUSHCHAR:
+    printf("OP_PUSHCHAR\t%c\n", c.u.c);
+    break;
+  case OP_PUSHCONST:
+    printf("OP_PUSHCONST\t%d\n", c.u.i);
+    break;
+  case OP_GREF:
+    printf("OP_GREF\t%i\n", c.u.i);
+    break;
+  case OP_GSET:
+    printf("OP_GSET\t%i\n", c.u.i);
+    break;
+  case OP_LREF:
+    printf("OP_LREF\t%d\n", c.u.i);
+    break;
+  case OP_LSET:
+    printf("OP_LSET\t%d\n", c.u.i);
+    break;
+  case OP_CREF:
+    printf("OP_CREF\t%d\t%d\n", c.u.r.depth, c.u.r.idx);
+    break;
+  case OP_CSET:
+    printf("OP_CSET\t%d\t%d\n", c.u.r.depth, c.u.r.idx);
+    break;
+  case OP_JMP:
+    printf("OP_JMP\t%d\n", c.u.i);
+    break;
+  case OP_JMPIF:
+    printf("OP_JMPIF\t%d\n", c.u.i);
+    break;
+  case OP_CALL:
+    printf("OP_CALL\t%d\n", c.u.i);
+    break;
+  case OP_TAILCALL:
+    printf("OP_TAILCALL\t%d\n", c.u.i);
+    break;
+  case OP_RET:
+    puts("OP_RET");
+    break;
+  case OP_LAMBDA:
+    printf("OP_LAMBDA\t%d\n", c.u.i);
+    break;
+  case OP_CONS:
+    puts("OP_CONS");
+    break;
+  case OP_CAR:
+    puts("OP_CAR");
+    break;
+  case OP_NILP:
+    puts("OP_NILP");
+    break;
+  case OP_CDR:
+    puts("OP_CDR");
+    break;
+  case OP_ADD:
+    puts("OP_ADD");
+    break;
+  case OP_SUB:
+    puts("OP_SUB");
+    break;
+  case OP_MUL:
+    puts("OP_MUL");
+    break;
+  case OP_DIV:
+    puts("OP_DIV");
+    break;
+  case OP_MINUS:
+    puts("OP_MINUS");
+    break;
+  case OP_EQ:
+    puts("OP_EQ");
+    break;
+  case OP_LT:
+    puts("OP_LT");
+    break;
+  case OP_LE:
+    puts("OP_LE");
+    break;
+  case OP_STOP:
+    puts("OP_STOP");
+    break;
+  }
 }
 
 void
 pic_dump_irep(pic_state *pic, struct pic_irep *irep)
 {
-  int i;
+  unsigned i;
 
   printf("## irep %p\n", (void *)irep);
   printf("[clen = %zd, argc = %d, localc = %d]\n", irep->clen, irep->argc, irep->localc);
diff --git a/src/error.c b/src/error.c
index e849026b..6203a767 100644
--- a/src/error.c
+++ b/src/error.c
@@ -25,12 +25,15 @@ pic_error(pic_state *pic, const char *msg)
 void
 pic_errorf(pic_state *pic, const char *msg, size_t n, ...)
 {
+  UNUSED(n);
   pic_error(pic, msg);
 }
 
 void
 pic_abort(pic_state *pic, const char *msg)
 {
+  UNUSED(pic);
+
   fprintf(stderr, "abort: %s\n", msg);
   fflush(stderr);
   abort();
@@ -39,6 +42,8 @@ pic_abort(pic_state *pic, const char *msg)
 void
 pic_warn(pic_state *pic, const char *msg)
 {
+  UNUSED(pic);
+
   fprintf(stderr, "warn: %s\n", msg);
 }
 
diff --git a/src/gc.c b/src/gc.c
index a71af550..1b61d4f1 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -121,6 +121,8 @@ pic_calloc(pic_state *pic, size_t count, size_t size)
 void
 pic_free(pic_state *pic, void *ptr)
 {
+  UNUSED(pic);
+
   free(ptr);
 }
 
diff --git a/src/pair.c b/src/pair.c
index 4495b641..2016c362 100644
--- a/src/pair.c
+++ b/src/pair.c
@@ -48,6 +48,8 @@ pic_cdr(pic_state *pic, pic_value obj)
 bool
 pic_list_p(pic_state *pic, pic_value obj)
 {
+  UNUSED(pic);
+
   while (pic_pair_p(obj)) {
     obj = pic_pair_ptr(obj)->cdr;
   }
diff --git a/src/proc.c b/src/proc.c
index 3509d479..fa2cabbb 100644
--- a/src/proc.c
+++ b/src/proc.c
@@ -50,6 +50,7 @@ pic_proc_cv_init(pic_state *pic, struct pic_proc *proc, size_t cv_size)
 int
 pic_proc_cv_size(pic_state *pic, struct pic_proc *proc)
 {
+  UNUSED(pic);
   return proc->env ? proc->env->valuec : 0;
 }
 
diff --git a/src/var.c b/src/var.c
index 92afb717..6bbd0331 100644
--- a/src/var.c
+++ b/src/var.c
@@ -27,6 +27,7 @@ pic_var_new(pic_state *pic, pic_value init, struct pic_proc *conv /* = NULL */)
 pic_value
 pic_var_ref(pic_state *pic, struct pic_var *var)
 {
+  UNUSED(pic);
   return var->value;
 }
 
@@ -42,6 +43,7 @@ pic_var_set(pic_state *pic, struct pic_var *var, pic_value value)
 void
 pic_var_set_force(pic_state *pic, struct pic_var *var, pic_value value)
 {
+  UNUSED(pic);
   var->value = value;
 }
 
diff --git a/src/write.c b/src/write.c
index 614fcb9e..e4ced267 100644
--- a/src/write.c
+++ b/src/write.c
@@ -33,6 +33,8 @@ write_str(pic_state *pic, struct pic_string *str)
   size_t i;
   const char *cstr = str->str;
 
+  UNUSED(pic);
+
   for (i = 0; i < str->len; ++i) {
     if (cstr[i] == '"' || cstr[i] == '\\') {
       putchar('\\');