diff --git a/libpsx/include/stdio.h b/libpsx/include/stdio.h
index a790aab..6ffd4e0 100644
--- a/libpsx/include/stdio.h
+++ b/libpsx/include/stdio.h
@@ -72,6 +72,8 @@ typedef struct
 	unsigned int error;
 }FILE;
 
+extern FILE *const stdin, *const stdout, *const stderr;
+
 /* Console functions */
 
 int putchar(int c);
diff --git a/libpsx/src/libc.c b/libpsx/src/libc.c
index 7f0b0f5..55ab413 100644
--- a/libpsx/src/libc.c
+++ b/libpsx/src/libc.c
@@ -26,7 +26,7 @@ static unsigned int __sio_cr_mapped = 0;
 
 #define NUM_OF_FILE_STRUCTS		259
 
-FILE file_structs[NUM_OF_FILE_STRUCTS]  =
+static FILE file_structs[NUM_OF_FILE_STRUCTS]  =
 {
 		[0] = // stdin
 		{
@@ -63,9 +63,9 @@ FILE file_structs[NUM_OF_FILE_STRUCTS]  =
 		},
 };
 
-FILE *stdin = &file_structs[0];
-FILE *stdout = &file_structs[1];
-FILE *stderr = &file_structs[2];
+FILE *const stdin = &file_structs[0];
+FILE *const stdout = &file_structs[1];
+FILE *const stderr = &file_structs[2];
 
 #define IS_CONS_IN(f)	(f->fildes == 0)
 #define IS_CONS_OUT(f)	(f->fildes == 1 || f->fildes == 2)