I'm trying to sscanf to read a bunch of successive fixed length strings but it's not working very well. I can print a fixed length string thusly:

sprintf('%.5s', 'aaaaabbbbb');

But if I try to use %.5s to read a fixed length string (eg. the first 5 bytes of an input string) it doesn't work. eg.

var_dump(sscanf('aaaaabbbbb', '%.5s'));

If I do that var_dump returns NULL and I get the following Warning:

Warning: sscanf(): Bad scan conversion character "."

I tried %5s in addition to %.5s but that doesn't work as desired either. eg.

var_dump(sscanf('aa aabbbbb', '%5s'));

That returns this:

array(1) {
  [0]=>
  string(2) "aa"
}

What I'd want it to return is this:

array(1) {
  [0]=>
  string(5) "aa aa"
}

Any ideas?

sscanf读取字符串错误