Function Prototype

All functions look like this:

void php3_foo(INTERNAL_FUNCTION_PARAMETERS) { }

Even if your function doesn't take any arguments, this is how it is called.

Function Arguments

Arguments are always of type pval. This type contains a union which has the actual type of the argument. So, if your function takes two arguments, you would do something like the following at the top of your function:

Example B-1. Fetching function arguments pval *arg1, *arg2; if (ARG_COUNT(ht) != 2 || getParameters(ht,2,&arg1,&arg2)==FAILURE) { WRONG_PARAM_COUNT; }

NOTE: Arguments can be passed either by value or by reference. In both cases you will need to pass &(pval *) to getParameters. If you want to check if the n'th parameter was sent to you by reference or not, you can use the function, ParameterPassedByReference(ht,n). It will return either 1 or 0.

When you change any of the passed parameters, whether they are sent by reference or by value, you can either start over with the parameter by calling pval_destructor on it, or if it's an ARRAY you want to add to, you can use functions similar to the ones in internal_functions.h which manipulate return_value as an ARRAY.

Also if you change a parameter to IS_STRING make sure you first assign the new estrdup()'ed string and the string length, and only later change the type to IS_STRING. If you change the string of a parameter which already IS_STRING or IS_ARRAY you should run pval_destructor on it first.

Variable Function Arguments

A function can take a variable number of arguments. If your function can take either 2 or 3 arguments, use the following: