diff --git a/include/picrin/blob.h b/include/picrin/blob.h
index ff8f7028..7b99885d 100644
--- a/include/picrin/blob.h
+++ b/include/picrin/blob.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef BLOB_H__
-#define BLOB_H__
+#ifndef PICRIN_BLOB_H__
+#define PICRIN_BLOB_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/cont.h b/include/picrin/cont.h
index 7c888bce..2cb82f16 100644
--- a/include/picrin/cont.h
+++ b/include/picrin/cont.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef CONT_H__
-#define CONT_H__
+#ifndef PICRIN_CONT_H__
+#define PICRIN_CONT_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/error.h b/include/picrin/error.h
index 5a4e67d0..b3b6d6ae 100644
--- a/include/picrin/error.h
+++ b/include/picrin/error.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef ERROR_H__
-#define ERROR_H__
+#ifndef PICRIN_ERROR_H__
+#define PICRIN_ERROR_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/gc.h b/include/picrin/gc.h
index 19399810..cb3ed2c6 100644
--- a/include/picrin/gc.h
+++ b/include/picrin/gc.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef GC_H__
-#define GC_H__
+#ifndef PICRIN_GC_H__
+#define PICRIN_GC_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/irep.h b/include/picrin/irep.h
index 3238694c..657d71f1 100644
--- a/include/picrin/irep.h
+++ b/include/picrin/irep.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef IREP_H__
-#define IREP_H__
+#ifndef PICRIN_IREP_H__
+#define PICRIN_IREP_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/lib.h b/include/picrin/lib.h
index accffbf4..3d85cf1a 100644
--- a/include/picrin/lib.h
+++ b/include/picrin/lib.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef LIB_H__
-#define LIB_H__
+#ifndef PICRIN_LIB_H__
+#define PICRIN_LIB_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/macro.h b/include/picrin/macro.h
index 00c72e83..b02ebf11 100644
--- a/include/picrin/macro.h
+++ b/include/picrin/macro.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef MACRO_H__
-#define MACRO_H__
+#ifndef PICRIN_MACRO_H__
+#define PICRIN_MACRO_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/pair.h b/include/picrin/pair.h
index fbfd64ad..a9f133a3 100644
--- a/include/picrin/pair.h
+++ b/include/picrin/pair.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef PAIR_H__
-#define PAIR_H__
+#ifndef PICRIN_PAIR_H__
+#define PICRIN_PAIR_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/parse.h b/include/picrin/parse.h
index 65708855..a1784f87 100644
--- a/include/picrin/parse.h
+++ b/include/picrin/parse.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef PARSE_H__
-#define PARSE_H__
+#ifndef PICRIN_PARSE_H__
+#define PICRIN_PARSE_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/port.h b/include/picrin/port.h
index a94ac9b2..2064d9bf 100644
--- a/include/picrin/port.h
+++ b/include/picrin/port.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef PORT_H__
-#define PORT_H__
+#ifndef PICRIN_PORT_H__
+#define PICRIN_PORT_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/proc.h b/include/picrin/proc.h
index bb04bd4b..11c4ff82 100644
--- a/include/picrin/proc.h
+++ b/include/picrin/proc.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef PROC_H__
-#define PROC_H__
+#ifndef PICRIN_PROC_H__
+#define PICRIN_PROC_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/value.h b/include/picrin/value.h
index a63705a6..658d2f5c 100644
--- a/include/picrin/value.h
+++ b/include/picrin/value.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef VALUE_H__
-#define VALUE_H__
+#ifndef PICRIN_VALUE_H__
+#define PICRIN_VALUE_H__
 
 #if defined(__cplusplus)
 extern "C" {
diff --git a/include/picrin/var.h b/include/picrin/var.h
index b37c0ae2..bc098200 100644
--- a/include/picrin/var.h
+++ b/include/picrin/var.h
@@ -2,8 +2,8 @@
  * See Copyright Notice in picrin.h
  */
 
-#ifndef VAR_H__
-#define VAR_H__
+#ifndef PICRIN_VAR_H__
+#define PICRIN_VAR_H__
 
 #if defined(__cplusplus)
 extern "C" {