calling a function within a function

[boen_robot]

when output_header gets called, don;t we also call the inner function function(username) (by setting its value to false)

No.The very idea of the "if" is to prevent exactly THAT scenario.When output_header gets called, it checks if it can call the inner function, and calls it only if it can. A boolean false does not translate to a function that can be called, so no function is ever called within output_headers in that case.

[jimfog]

No. The very idea of the "if" is to prevent exactly THAT scenario. When output_header gets called, it checks if it can call the inner function, and calls it only if it can. A boolean false does not translate to a function that can be called, so no function is ever called within output_headers in that case.

The thing that confused my is that the Is_callable had as an argument $function.We can use anything there provided that it is something that cannot be called. I used this for example:

if (is_callable('tel')) {    $function($username);

and it still did the job.

[jimfog]

No. A boolean false does not translate to a function that can be called, so no function is ever called within output_headers in that case.

The above phrase though, completes the puzzle-at least for now.