Free Computer Books

The extension API includes a rich collection of macros that allows you to
return values from your functions. These macros come in two main flavors.
The first is of the form RETVAL_type(), which sets the return value but your C
code keeps on executing. This is usually used if you still want to do some clean-
ing up before returning control over to the scripting engine. You will then need
to use the C return statement “return;” to return to PHP. The latter, which are
the more popular macros, are of the form RETURN_type(), which set the return
type and return control back to PHP. Table 15.2 explains most of the existing
macros. (more…)

PHP’s API for allocating memory from the heap is almost identical to the stan-
dard C API. When writing extensions, use the following API functions that
correspond to their C counterparts (and therefore are not explained): (more…)

Instead of slowly explaining some of the building blocks of the scripting
engine, this section dives into coding an extension, so do not worry if you don’t
see the whole picture right away.
Imagine you are writing a web site but need a function, which will repeat
a string n times. Writing this in PHP is simple: (more…)

“If the code and the comments disagree, then both are probably wrong.”–
Norm Schryer

One of the main reasons for PHP’s success is the large amount of available
extensions. No matter what a web developer might need, he’ll most probably
find it in the PHP distribution, including extensions that support various
databases, graphic file formats, compression, XML technologies, and lots
more. (more…)