In PHPoC, function has to be declared before being called. Meanwhile, PHP can call function before declaring.
It is not allowed to use the duplicated argument names in a user-defined function.
If there is no returning value, user-defined function returns zero (0) instead of NULL.
Not support for returning by reference.
Not support for variable functions.
Not support for anonymous functions
PHPoC supports for various internal functions. Refer to a document named PHPoC Internal Functions to know how to use those functions.