If I open a file for writing and immediately close it:

  fclose(fopen("foo", "w"));

the file "foo" will be truncated to zero length if it exists.

However, I I do this with a memory buffer, e.g.
    char arr[] = { 'a','a','a','a','a','a','a','a','a','a', 0};
    fclose(fmemopen(arr, 10, "w"));
I would expect that arr[0] would have a null byte.

But it doesn't. Is this a bug?

-- 
Nick