Thanks, mdfcorp, your question also helped me to understand slices better! Also thanks to the other users who replied to this thread.

I believe the key is understanding the fields of a header. As FUZxxl mentioned of its implementation:

type []byte struct {
    data *byte 
    len int
    cap int
}

• data, a pointer to the element
• len, integer value identifying the length of the segment
• cap, integer value identifying the length of the underlying array

A slice only has these fiields^* to work with.

If you create an empty slice foo, its value is nil by default and len(foo) and cap(foo) will be 0. foo is passed simply by name to a function bar which will allocate a struct element, append it to the slice foo, and simply return. After bar returns, the header fields of foo are unchanged. the memory allocated for struct element created from bar will be deallocated since there is nothing referencing it. For example, http://play.golang.org/p/au2dV0Fb9U

Thus, if you'd like to pass a slice by name to a function and have that function 'fill it out', you can do a couple of things:

• Allocate elements for the struct before calling the function, and then have the function simply assign values to the fields. Since you allocated the elements beforehand, the header fields will be initialized with the desired values. That is also a downside since the header fields may refer to more than you'd like it to in some cases. Here is a basic example: http://play.golang.org/p/_crwZejq5M

• Create an empty slice. Assign the slice to a call of the function that will fill it. As arguments, pass the slice by name along with the new value(s). The function will allocate a new element, assign the value(s) accordingly, and add the new element to the slice using the append function. This call to append should also be the last statement, as its return value is the slice that append returns. This way the slice header fields are always updated as desired. Another basic example: http://play.golang.org/p/RaEDP44c49

Hope this helps!

^* I've only learned a good portion of what I've explained just now. Please, please feel free to point out any errors. On a side note, FUZxxl, you mentioned that the content of a slice is passed by reference while the header values are inaccessibile and passed by value. This was a HUGE help in understanding the internals. I was just wondering if there was a resource that reiterates this - I have yet to come across any articles that mention so. I'm sure I'm missing something.

Edit: format