diff --git a/18-interrupts/cpu/idt.h b/18-interrupts/cpu/idt.h
index 27bfac5..e8549a3 100644
--- a/18-interrupts/cpu/idt.h
+++ b/18-interrupts/cpu/idt.h
@@ -28,9 +28,8 @@ typedef struct {
 } __attribute__((packed)) idt_register_t;
 
 #define IDT_ENTRIES 256
-idt_gate_t idt[IDT_ENTRIES];
-idt_register_t idt_reg;
-
+extern idt_gate_t idt[IDT_ENTRIES];
+extern idt_register_t idt_reg;
 
 /* Functions implemented in idt.c */
 void set_idt_gate(int n, u32 handler);