[RESOLVED] php code flow

[webnick]

When a script is executed, does the PHP engine run one line at a time?
If a line has an error or infinte loop, does that kill the script?

Or does it go to a subroutine while the rest of the script loads?

Thank you

[ClarkF1]

If an error is found the script will produce an error or warning depending on what the error is and the error reporting settings on the server.

For an infinite loop, it will go through the loop until the maximum execution time for scripts is reached.

As far as I know it goes through line by line. As soon as it hits an error that produces a warning it outputs that error but if that error is part of a loop or in a function that is called multiple times you'll see that warning multiple times.

[NogDog]

At runtime, PHP actually compiles the entire script. Then, if there are no parsing/compiling errors, it begins execution of the script from the compilation result (which is in real or virtual memory only until no longer needed). Therefore, there are two general types of errors you can encounter: those which occur during the parse/compile phase (such as syntax errors) and those that occur during the execution phase (such as memory usage errors resulting from infinite loops).

Fatal parse/compile errors will prevent script execution and nothing in it will actually get processed. Runtime errors may kill the script at the moment they occur, or simply throw a warning or notice, depending on the type of error. You can use the set_error_handler function to define your own error-handling of runtime (not compile time) errors which are not of the following types: E_ERROR, E_PARSE, E_CORE_ERROR, E_CORE_WARNING, E_COMPILE_ERROR, E_COMPILE_WARNING, and most of E_STRICT.

[webnick]

That's what I was wondering. So a bad loop would keep other parts of the script from executing. Thanks for the useful help!