Autoconf

In a simple application, you'd probably just add something to your Makefile's CFLAGS and LDFLAGS lines like of the following:

CFLAGS = ${CFLAGS} -I/usr/local/foobar/include
LDFLAGS = ${LDFLAGS} -lfoobar -L/usr/local/foobar/lib

Anyone else building your application who doesn't have libfoobar, or has it installed in another location, would get treated to a cryptic error message and left to his own devices to determine what went wrong.

Most OSS applications developed in the past decade or soPHP includedtake advantage of a utility called autoconf to generate a complicated configure script from a set of simple macros. This generated script then does the work of looking for where those dependent libraries and their headers are installed. Based on this information, a package can customize that build line, or provide meaningful error messages before compilation time has been wasted on a configuration that won't work.

In building PHP extensions, whether or not you plan to release them to the public, you'll take advantage of this same autoconf mechanism. Even if you're already familiar with autoconf, take a minute to read through this chapter as PHP includes several custom macros not found in the usual autoconf setup.

Unlike traditional autoconf setups, where a central configure.in file at the base of the package contains all configuration macros, PHP only uses configure.in to manage the coordination of several smaller config.m4 scripts located throughout the source tree, including one for every extension, SAPI, the Core itself, and the Zend Engine.

You've already seen a very simple version of this config.m4 script in previous chapters. In the coming pages, you'll add additional autoconf syntax to this file, allowing more configuration time information to be collected by your extension.


Looking for Libraries

The PHP Life Cycle

Variables from the Inside Out

Memory Management

Setting Up a Build Environment

Your First Extension

Returning Values

Accepting Parameters

Working with Arrays and HashTables

The Resource Data Type

PHP4 Objects

PHP5 Objects

Startup, Shutdown, and a Few Points in Between

INI Settings

Accessing Streams

Implementing Streams

Diverting the Stream

Configuration and Linking

Extension Generators

Setting Up a Host Environment

Advanced Embedding

Appendix A. A Zend API Reference

Appendix B. PHPAPI

Appendix C. Extending and Embedding Cookbook

Appendix D. Additional Resources

show all menu



Extending and Embedding PHP
Extending and Embedding PHP
ISBN: 067232704X
EAN: 2147483647
Year: 2007
Pages: 175
Authors: Sara Golemon
Similar book on Amazon

Flylib.com © 2008-2017.
If you may any questions please contact us: flylib@qtcs.net