Zero-length arrays are allowed in GNU C. They are very useful as the last element of a structure which is really a header for a variable-length object:
struct line { int length; char contents[0]; }; { struct line *thisline = (struct line *) malloc (sizeof (struct line) + this_length); thisline->length = this_length; }
In standard C, you would have to give contents
a length of 1, which
means either you waste space or complicate the argument to malloc
.