diff --git a/src/ft_read.s b/src/ft_read.s
index 3cbabc3..5eb489c 100644
--- a/src/ft_read.s
+++ b/src/ft_read.s
@@ -7,6 +7,7 @@ section .text
 
 ft_read:
 	cmp rsi, 0				; check if the buffer is NULL
+	mov rax, -1				; set the return value to -1 (for error) (UB)
 	je .exit				; if true go to exit
 	mov rax, 0				; syscall 0 is for read
 	syscall					; call the system call read