Question regarding patches

[Shraddha Kamat]

Sorry if this is not relevant to kernel. But since I am 
patching the kernel - Please consider this as a uber beginner
question to ask on this mailing list - forgive me for that.

Now my question is - 

What "@@ -321,7 +321,8 @@" mean in this snippet from the patch -  

diff --git a/exec.h b/exec.h
index 722c620..6abb687 100644
--- a/exec.h
+++ b/exec.h
@@ -321,7 +321,8 @@ static void acct_arg_size(struct linux_binprm *bprm,
unsigned long pages);

-- Shraddha