Peter Dimov wrote:

Ken MacKay wrote:

...

I found that I can use bind without specifying the boost namespace when a placeholder (eg, _1) is used. If I don't use a placeholder in the bind expression, then the compiler properly complains that "bind" is undeclared. I am using gcc 3.3.5 on QNX 6.3.2.

This behavior is caused by a C++ rule known as argument-dependent lookup (ADL) or Koenig lookup. In an expression of the form f(x, y), f is (also) looked up in the ("associated") namespaces of x and y. Since _1 is usually of type boost::arg<1>, boost is an associated namespace for it and the function "bind" is found without an explicit boost:: qualification.

OK, that makes sense. Thank you Peter. -Ken