Stack Allocations

[<msoda () aspre net>]

Hey all,

I have been reading up on buffer overflows and have noticed something odd
with gcc assembly output.  Consider the following:

void func()
{
   char buf[15];
}

main()
{
   func();
}

When running 'gcc -S' it shows that 24 bytes are allocated on the stack
for buf[].  I thought it should allocate only 16 bytes.  It works fine, it
just makes no sense to me.  If I tweak the assembly and change it to 16
bytes and also change the offsets to %ebp that reference it, it works fine
also.

Does anyone know why gcc does this?  My need to understand everything is
killing me!

-Marc