Hi,
Sounds like you are coming from compiler programming language like C++ or Java.
OK, let's see if i can answer some of your questions.
spr21hear wrote:How do I determine if the "run" has been completed, and so, my code has no errors?
Because PHP does not need to get compiled there is nothing similar like the errors a compiler would throw.
PHP code is something similar to the intermediate language you get after compiling. So any errors still left in the code do only occur at the time or access.
How the error is presentes depends on the settings, so be sure to not hide your error messages or log them properly.
spr21hear wrote:That is (conversely): Does "Notice" statements mean that my code has run-time errors?
There are multiple levels of error levels defined in PHP. Messages containing the Word Error (including Compile_Error, Core_Error, etc) are terminating your script, because PHP does not have a failback for those. All other levels (like warning, notice, strict, deprecated) are often the product of sloppy programming. Mostly PHP can handle them by a failback without issue, but sometimes the failback is not what the programmer wanted to achieve. So you can and should solve these messages, but of you hide the error messages your code will in most cases run.
spr21hear wrote:And, similarly: Does "no result"; ie, a blank page* resulting from the run, mean that my code has no run-time errors ? (* this code has no "display"; eg, html commands, only php)
No. A blank screen (white screen of death) is often a bad sign in PHP, because in almost all cases you want to end in any type of screen response.
Be sure you display your errors on your development environment and hide them on production environments.