Question: Is it possible to edit the text within a cell in datatables. So that when the user double clicks on the cell it becomes editable ?

Thanks

Answer: 
If you already know that `str` is non-null:

```
if (!*str) {
    // empty string
}

```

Otherwise:

```
if (!str || !*str) {
    // empty string
}

```

Forget about `strlen()`.
I would definitely go with `strlen(str) == 0`, just for clarity.

The function should be implemented something like this:

```
int strlen(char *s) {
  int len = 0;
  while(*(s++)) len++;
  return len;
}

```

so there will be no big overhead.

**Edit:** assuming you are sure that the string is actually zero terminated.