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 .