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<TITLE>PHP3 Frequently Asked Questions</TITLE>
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<H1>PHP3 Frequently Asked Questions</H1>
<!-- The website should stop chopping. -->
<P>
This is a list of Frequently Asked Questions about PHP3 and
their answers. If you have suggestions or additions, send them to
<A HREF="mailto:php3@lists.php.net">php3@lists.php.net</A>.
<P>
<HR noshade>
<DL>
<DT><a HREF="#1">1. General Information</A></DT>
<DT><a HREF="#2">2. Obtaining PHP3</A></DT>
<DT><a HREF="#3">3. Installation</A></DT>
<DT><a HREF="#4">4. Common Problems</A></DT>
<DT><a HREF="#5">5. Using PHP3</A></DT>
<DT><a HREF="#6">6. New Features</A></DT>
<DT><a HREF="#7">7. Common Problems</A></DT>
<DT><a HREF="#8">8. Migrating from PHP2 to PHP3</A></DT>
</DL>
<HR noshade>
<A NAME="1">
<H2>1. General Information</H2>
</A>
<DL>
<DT><B>
<a name="1.1">1.1</a> What is PHP3?
</B></DT>
<DD>
From the <A href="http://www.php.net/manual/">manual</A>:
<BLOCKQUOTE>
<P>PHP Version 3.0 is an HTML-embedded scripting
language. Much of its syntax is borrowed from C, Java and Perl with a
couple of unique PHP-specific features thrown in. The goal of the language
is to allow web developers to write dynamically generated pages quickly.
</BLOCKQUOTE>
<P>
</DD>
<DT><B>
<a name="1.2">1.2</a> What is its relation to PHP/FI?
</B></DT>
<DD>
PHP3 is the successor to PHP/FI 2.0.
<P>
</DD>
<DT><B>
<a name="1.3">1.3</a> Can I run both PHP/FI 2.0 and PHP3 at the same time?
</B></DT>
<DD>
Yes, PHP3 was written so as to not interfere with an existing PHP/FI 2 installation.
Instructions for building Apache 1.3.0 with both PHP/FI 2 and PHP3 modules can be
found <a href="php2.php3">HERE</a>. A different spin on this is
<a href="http://www.jeo.net/php/both.htm">HERE</a>, although the first step where
the PHP2 regex code is substituted with the PHP3 regex code seems redundant. The
two regex dirs are pretty much identical.
<P>
<DT><B>
<a name="1.4">1.4</a> What are the differences between PHP3 and PHP/FI 2.0?
</B></DT>
<DD>
For a complete list of the changes, read the <A
href="changes.php3">CHANGES</A> file included in the PHP3
distribution. Some highlights:
<UL>
<LI>All-new parser.
<LI>Persistent database connections.
<LI>A native Windows95/NT port.
<LI>IMAP, SNMP, and LDAP extensions.
</UL>
<P>
</DD>
<DT><B>
<a name="1.5">1.5</a> I heard it's possible to access Microsoft SQL Server from PHP3. How?
</B></DT>
<DD>
On Windows 95/NT machines, you can simply use the included ODBC support
and the correct ODBC driver.
<P>On Unix machines, you can use the Sybase-CT driver
to access Microsoft SQL Servers because they are (at
least mostly) protocol-compatible. Sybase has made a <A
href="/extra/ctlib-linux-elf.tar.gz">free version of the necessary
libraries for Linux systems</A>. For other Unix operating systems,
you need to contact Sybase for the correct libraries. Also see
the answer to the next question - 1.6.
<P>
</DD>
<DT><B>
<a name="1.6">1.6</a> Can I access Microsoft Access databases?
</B></DT>
<DD>
Yes. You already have all the tools you need if you are running
entirely under Windows 95/98 or NT, where you can use ODBC and Microsoft's
ODBC drivers for Microsoft Access databases.<P>
If you are running PHP on a Unix box and want to talk to MS-Access on
a Windows box you will need Unix ODBC drivers.
<A href="http://www.openlinksw.com/">OpenLink Software</A> has Unix-based
ODBC drivers that can do this. There is a free pilot program where you
can download an evaluation copy that doesn't expire and prices start at
$675 for the commercial supported version.
<P>Another alternative is to use an SQL server that has
Windows ODBC drivers and use that to store the data, which you can
then access from Microsoft Access (using ODBC) and PHP3 (using the
built-in drivers), or to use an intermediary file format that Access
and PHP3 both understand, such as flat-files or dBase databases.
On this point Tim Hayes from OpenLink software writes:
<blockquote><blockquote>
Using another database as an intermediary is not a good idea, when you can
use ODBC from PHP3 straight to your database - i.e. with OpenLink's drivers. If
you do need to use an intermediary file format, OpenLink have now released
Virtuoso (a virtual database engine) for NT, Linux and other unix platforms.
Please visit our
<A href="http://www.openlinksw.com">website</A> for a free download.
</blockquote></blockquote>
<P>One option that has proven successful is to use MySQL and its
MyODBC drivers on Windows and synchronizing the databases. Steve Lawrence
writes:
<blockquote><blockquote>
<ol>
<li> Install MySQL on your platform according to instructions with MySQL.
Latest available from www.mysql.org (get it from your mirror!). No special
configuration required except when you set up a database, and configure the
user account, you should put % in the host field, or the host name of the
windows computer you wish to access MySQL with. Make a note of your server
name, username, and password.<P>
<li> Download the MyODBC for windows driver from the MySQL site. Latest
release is myodbc-2_50_19-win95.zip (NT available too, as well as source
code). Install it on your windows machine. You can test the operation with
the utilities included with this program.<P>
<li> Create a user or system dsn in your ODBC administrator, located in the
control panel. Make up a dsn name, enter your hostname, user name, password,
port, etc for you MySQL database configured in step 1.<P>
<li> Install Access with a full install, this makes sure you get the proper
add-ins.. at the least you will need ODBC support and the linked table
manager.<P>
<li> Now the fun part! Create a new access database. In the table window right
click and select Link Tables, or under the file menu option, select Get
External Data and then Link Tables. When the file browser box comes up,
select files of type: ODBC. Select System dsn and the name of your dsn
created in step 3. Select the table to link, press ok, and presto! you can
now open the table and add/delete/edit data on your MySQL server! You can
also build queries, import/export tables to MySQL, build forms and reports,
etc.<P>
</ol>
<b>Tips and Tricks:</b>
- You can construct your tables in access and export them to MySQL, then
link them back in. That makes table creation quick.<br>
- When creating tables in access, you must have a primary key defined in
order to have write access to the table in access. Make sure you create a
primary key in MySQL before linking in access.<br>
- If you change a table in MySQL, you have to re-link it in access. Go to
tools&gt;add-ins&gt;linked table manager, cruise to your ODBC DSN, and select the
table to re-link from there. you can also move your dsn source around there,
just hit the always prompt for new location checkbox before pressing ok.
</blockquote></blockquote>
<P>
</DD>
<DT><B>
<a name="1.7">1.7</a> Is there a PHP3 mailing list?
</B></DT>
<DD>
Of course! To subscribe, send mail to
<CODE>php3-subscribe@lists.php.net</CODE>. You don't need to include
anything special in the subject or body of the message.
<P>To unsubscribe, send mail to <CODE>php3-unsubscribe@lists.php.net</CODE>.
<P>
</DD>
<DT><B>
<a name="1.8">1.8</a> Help! I can't seem to subscribe to the mailing list!
</B></DT>
<DT><B>
Help! I can't seem to unsubscribe from the mailing list!
</B></DT>
<DD>
If you have problems subscribing to or unsubscribing from the
PHP3 mailng list, it may be because the mailing list software
can't figure out the correct mailing address to use. If
your email address was <CODE>joeblow@example.com</CODE>,
you can send your subscription request to
<CODE>php3-subscribe-joeblow=example.com@lists.php.net</CODE>,
or your unsubscription request to
<CODE>php3-unsubscribe-joeblow=example.com@lists.php.net</CODE>.
<P>
</DD>
<DT><B>
<a name="1.9">1.9</a> Is there an archive of the mailing list anywhere?
</B></DT>
<DD>
Yes, you will find a list of archive sites on the <a href="/support.php3">Support</a>
page.<P>
</DD>
<DT><B>
<a name="1.10">1.10</a> How did you do those pop-out windows for the Search and Mirror buttons?
</B></DT>
<DD>
Our site designer, Colin Viebrock (<A href="mailto:cmv@privateworld.com">cmv@privateworld.com</A>), says:
<BLOCKQUOTE>
<P>Those fancy pop-out layers are done with Dynamic HTML (DHTML), Cascading Style Sheets (CSS) and Javascript (version 1.2).<P>
There are plenty of references on the web about DHTML and CSS, including:
<P><UL>
<LI>CSS Level 1 Spec: <A HREF="http://www.w3.org/TR/REC-CSS1">www.w3.org/TR/REC-CSS1</A>
<LI>Macromedia's DHTML Zone: <A HREF="http://www.dhtmlzone.com/index.html">www.dhtmlzone.com/index.html</A>
<LI>Webreference's DHTML Lab: <A HREF="http://www.webreference.com/dhtml/">www.webreference.com/dhtml/</A>
<LI>Guide to Cascading Style Sheets: <A HREF="http://www.htmlhelp.com/reference/css/">www.htmlhelp.com/reference/css/</A>
<LI>Dynamic Duo - Cross-Browser DHTML: <A HREF="http://www.dansteinman.com/dynduo/">www.dansteinman.com/dynduo/</A>
<LI>Netscape's Guide to JS 1.2: <A HREF="http://developer.netscape.com/docs/manuals/communicator/jsguide/js1_2.htm">developer.netscape.com/docs/manuals/communicator/jsguide/js1_2.htm</A>
</UL>
<P>But your best source of information is to view the source code to the pages on the PHP site.
To see the actual DHTML/Javascript code, use your browser's "View Source" function. To see how this code was
generated dynamically using PHP3, click on the "Source" button in the upper-right corner of any PHP page. You
will probably also want to view the source of the "shared.inc" file - there is a link to it at the bottom of every
source page.
</BLOCKQUOTE><P>
</DD>
<DT><B>
<a name="1.11">1.11</a> Can I access Empress RDBMS databases?
</B></DT>
<DD>
Yes. PHP 3.0.6 and Empress RDBMS v8.10 and higher are compatible.
<P>
You already have all the tools you need if you are running entirely under
Windows 95/98 or NT, where you can use ODBC and the Empress ODBC driver for
Windows.
<P>
If you are running PHP on a Unix box and want to access Empress databases, you
can link
the Empress ODBC client driver directly into the PHP unified ODBC API.
<BR>
<I>Note that does NOT make PHP an ODBC client. The unified ODBC interface
simplies uses the ODBC application program interface (API).</I>
<P>
Because Empress uses the PHP unified ODBC interface it has very little explicit
Empress specific syntax. It is of course possible to use Empress specific SQL
in the SQL statements themselves, but this does not affect the interface.
It is a good general policy to stick to ANSI standard SQL whenever
possible.
<P>
<DL>
<DT><B>Empress Specifics: </B> The only item which is specific to Empress in
PHP is that there are two methods for specifying the DNS in the
<code>odbc_connect ()</code> and <code>odbc_pconnect ()</code> functions.
The connect syntax is:
<DL>
<DT><code>odbc_connect (dsn, user_id, password)</code>
<DT><code>odbc_pconnect (dsn, user_id, password)</code>
</DL>
For Empress dsn can be specified as either:
<DL>
<DT>Data source name
<DD>This is the logical database name specified in the ODBC.INI file.
<DT>A full connection string, as specified in the ODBC standard.
<DD>
eg<BR>
dsn="DATABASE=<i>db_name</i>;SERVER=<i>server_name</i>;PORT=<i>server_port</i>"
<P>
<i>Note that there are other options for this string. But the three shown
above are the most important for use with PHP.</i>
</DL>
Which of these you use is up to you. There are advantages and disadvantages to both.
Using the full connection string means that you do NOT require an ODBC.INI file
to access the database. However, if you move the datasource, or change the port on
which the RDBMS server listens, you will have to modify every call to the
odbc_connect/pconnect function.
<BR>The choice is yours...
<P>
<DT><B>Empress Installation: </B>
In order to add the Empress interface to PHP you require an Empress RDBMS with
the Empress Connectivity option. If your PHP installation is on the same
platform as the RDBMS then setting EMPRESS_PATH to the installation directory
will automatically locate the Empress ODBC client driver. However, if the
PHP installation is on a separate platform from the RDBMS you will also
require an ODBC client on that platform, and you will need to specify the
location of the driver when configuring the PHP installation.
</DL>
</DD>
</DL>
</BODY>
</HTML>
</DL>
<HR noshade>
<A NAME="2">
<H2>2. Obtaining PHP3</H2>
</A>
<DL>
<DT><B>
<a name="2.1">2.1</a> Where can I obtain PHP3?
</B></DT>
<DD>
You can download PHP3 from any of the members of the
PHP3 network of sites. These can be found at <A
href="http://www.php.net/">http://www.php.net/</A>.
You can also use anonymous CVS to get the absolute latest
version of the source. For more information, go to <A
href="http://ca.php.net/cvsweb.cgi">http://ca.php.net/cvsweb.cgi</A>.
<P>
</DD>
<DT><B>
<a name="2.2">2.2</a> Are pre-compiled binary versions available?
</B></DT>
<DD>
Yes, although they are not always up to date. The Windows binary is
generally current, but the Unix binaries lag behind and are only available
for certain platforms. All download are available in the <a href="/downloads.php3">
Downloads</a> section.
<P>
</DD>
<DT><B>
<a name="2.3">2.3</a> Where can I get libraries needed to compile some of the optional
PHP3 extensions?
</B></DT>
<DD>
<B>Note:</B> Those marked with * are not thread-safe libraries, and
should not be used with PHP3 as a server module in the multi-threaded
Windows web servers (IIS, Netscape). This does not matter in Unix
environments, yet.
<UL>
<LI>LDAP (unix): <a href="ftp://ftp.openldap.org/pub/openldap/openldap-stable.tgz">ftp://ftp.openldap.org/pub/openldap/openldap-stable.tgz</a>
<LI>LDAP* (unix): <A href="ftp://terminator.rs.itd.umich.edu/ldap/ldap-3.3.tar.Z">ftp://terminator.rs.itd.umich.edu/ldap/ldap-3.3.tar.Z</A>
<LI>LDAP (unix/win): <A HREF="http://developer.netscape.com/tech/directory/downloads.html" TARGET="_top">Netscape Directory (LDAP) SDK 1.1</A>
There is also a free LDAP server at: <A href="ftp://ftp.critical-angle.com/pub/cai/slapd/">ftp://ftp.critical-angle.com/pub/cai/slapd/</A>.
<LI>Berkeley DB2 (Unix/Win): <A href="http://www.sleepycat.com/">http://www.sleepycat.com/</A>
<LI>SNMP* (Unix): <A href="http://www.ece.ucdavis.edu/ucd-snmp/">http://www.ece.ucdavis.edu/ucd-snmp/</A> (Note: PHP3 uses the native SNMP interface in Windows.)
<LI>GD* (Unix/Win): <A href="http://www.boutell.com/gd/#buildgd">http://www.boutell.com/gd/#buildgd</A>
<LI>mSQL* (Unix): <A href="http://www.hughes.com.au/">http://www.hughes.com.au/</A>
<LI>mSQL* (Win) : <A HREF="http://blnet.com/msqlpc/">MSQL PC Home Page</a>
<LI>MySQL (Unix): <A href="http://www.tcx.se/">http://www.tcx.se/</A>
<LI>IMAP* (Win/Unix): <A HREF="ftp://ftp.cac.washington.edu/imap/imap-4.4.tar.Z">ftp://ftp.cac.washington.edu/imap/imap-4.4.tar.Z</A>
<LI>Sybase-CT* (Linux, libc5): <A href="/extra/ctlib-linux-elf.tar.gz">Available locally</A>
<LI>FreeType (libttf): <A HREF="http://www.freetype.org/">http://www.freetype.org/</A>
<LI>ZLib (Unix/Win32): <A HREF="http://www.cdrom.com/pub/infozip/zlib/">http://www.cdrom.com/pub/infozip/zlib/</a>
<LI>expat XML parser (Unix/Win32): <A HREF="http://www.jclark.com/xml/expat.html">http://www.jclark.com/xml/expat.html</a>
<LI> PDFLib: <A HREF="http://www.ifconnection.de/~tm/software/pdflib/pdflib-0.6.tar.gz">http://www.ifconnection.de/~tm/software/pdflib/pdflib-0.6.tar.gz</A>
</UL>
<P>
</DD>
<DT><B>
<a name="2.4">2.4</a> How do I get these libraries to work?
</B></DT>
<DD>
You will need to follow instructions provided with the library. Some of
these libraries are detected automatically when you run the 'configure'
script of PHP3 (such as the GD library), and others you will have to
enable using '--with-EXTENSION' options to 'configure'. Run 'configure
--help' for a listing of these.
<P>
</DD>
<DT><B>
<a name="2.5">2.5</a> I got the latest version of the PHP3 source code from the CVS
repository on my Windows 95/NT machine, what do I need to compile it?
</B></DT>
<DD>
First, you will need Microsoft Visual C++ v5 (v4 may do
it also, but we do it with v5), and you will need to <A
href="http://www.php.net/win32/makeparser.zip">download Bison and
Flex</A>. You will need to put Bison and Flex somewhere in your
path, or add their location to your path. Then run the batch file
'makeparser' before compiling with MSVC. You also may need to edit
some settings in the project settings. You should be familier enough
with MSVC to know what to do ;).
<P>
</DD>
<DT><B>
<a name="2.6">2.6</a> Where do I find the Browser Capabilities File?
</B></DT>
<DD>
You can find PHP's own browscap.ini file at <a href="http://php.netvision.net.il/browscap/">http://php.netvision.net.il/browscap/</a>.
There is also another browscap.ini file at <a href="http://www.cyscape.com/asp/browscap/">http://www.cyscape.com/asp/browscap/</a>.
<P>
</DD>
</DL>
<HR noshade>
<A NAME="3">
<H2>3. Installation</H2>
</A>
<P>To install PHP3, follow the instructions in the <A
href="http://ca.php.net/cvsweb.cgi/INSTALL?rev=HEAD">INSTALL</A>
file located in the distribution. Windows
95 and NT users should also read the <A
href="http://ca.php.net/cvsweb.cgi/README.WIN32?rev=HEAD">README.WIN32</A>
file. There are also some helpful hints for Windows users here:
<a href="http://leonard.staff.imaginet.fr/Doc/php/configuration_NT.html">
http://leonard.staff.imaginet.fr/Doc/php/configuration_NT.html</a>.
<P>If you are trying to install PHP for use with Netscape's web server on
Unix see: <a href="http://www.webgenx.com/Kwazy/phpunix.html">http://www.webgenx.com/Kwazy/phpunix.html</a>
<DL>
<DT><B>
<a name="3.1">3.1</a> Where should my <i>php3.ini</i> file be located?
</B></DT>
<DD>
By default on UNIX it should be in <i>/usr/local/lib</i>. Most people will want
to change this at compile-time with the --with-config-file-path flag. You would, for
example, set it to something like:
<PRE>
--with-config-file-path=/etc
</PRE>
And then you would copy <i>php3.ini-dist</i> from the distribution to <i>/etc/php3.ini</i> and
edit it to make any local changes you want.
<P>
</DD>
<DT><B>
<a name="3.2">3.2</a> I installed PHP3 using RPMS, but Apache isn't processing the php3 pages! What's going on here?
</B></DT>
<DD>
<UL>
<LI>Assuming you installed Apache PHP completely with RPMS, you need to uncomment or add some or all of the following lines in your http.conf file:<BR>
<CODE># Extra Modules</CODE><BR>
<CODE>AddModule mod_php.c</CODE><BR>
<CODE>AddModule mod_php3.c</CODE><BR>
<CODE>AddModule mod_perl.c</CODE><BR>
<CODE># Extra Modules</CODE><BR>
<CODE>LoadModule php_module modules/mod_php.so</CODE><BR>
<CODE>LoadModule php3_module modules/libphp3.so</CODE><BR>
<CODE>LoadModule perl_module modules/libperl.so</CODE><BR>
<LI>And add:<BR>
<CODE>AddType application/x-httpd-php3 .php3</CODE><BR>
To the global properties, or to the properties of the VirtualDomain you want to have PHP3 support added to.
</UL><P></DD>
<DT><B>
<a name="3.3">3.3</a> I installed PHP3 using RPMS, but it doesn't compile with the database support I need! What's going on here?
</B></DT>
<DD>
Currently the RPM packagers are setting up the RPMS to install without database support to simplify installations AND because RPMS use /usr/ instead of the standard /usr/local/ directory for files.
You need to tell the RPM spec file which databases to support and the location of the <EM>top-level</EM> of your database server.<BR>
This example will explain the process of adding support for the popular MySQL database server, using the mod installation for Apache.<BR>
Of course all of this information can be adjusted for any database server that PHP3 supports.
I will assume you installed MySQL and Apache completely with RPMS for this example as well.
<UL>
<LI>First remove mod_php3<BR>
<CODE>rpm -e mod_php3</CODE><BR>
<LI>Then get the source rpm and INSTALL it, NOT --rebuild<BR>
<CODE>rpm -Uvh mod_php3-3.0.5-2.src.rpm</CODE><BR>
<LI>Then edit the /usr/src/redhat/SPECS/mod_php3.spec file<BR>
In the %build section add the database support you want, and the path.<BR>
For MySQL you would add <CODE>--with-mysql=/usr \</CODE><BR>
The %build section will look something like this:<BR>
<CODE>
./configure --prefix=/usr \<BR>
--with-apxs=/usr/sbin/apxs \<BR>
--with-config-file-path=/usr/lib \<BR>
--enable-debug=no \<BR>
--enable-safe-mode \<BR>
--with-exec-dir=/usr/bin \<BR>
--with-mysql=/usr \<BR>
--with-system-regex<BR>
</CODE>
<LI>Once this modification is made then build the binary rpm as follows:<BR>
<CODE>rpm -bb /usr/src/redhat/SPECS/mod_php3.spec </CODE><BR>
<LI>Then install the rpm<BR>
<CODE>rpm -ivh /usr/src/redhat/RPMS/i386/mod_php3-3.0.5-2.i386.rpm</CODE><BR>
</UL>
Make sure you restart Apache, and you now have PHP with MySQL support using RPM's.
<P>
</DD>
</DL>
<HR noshade>
<A NAME="4">
<H2>4. Common Problems</H2>
</A>
<DL>
<DT><B>
<a name="4.1">4.1</a> I got the latest version of PHP3 using the anonymous CVS service,
but there's no configure script!
</B></DT>
<DD>
You have to have the GNU autoconf package installed so you can
generate the configure script from configure.in. Just run
<CODE>autoconf</CODE> in the top-level directory after getting
the sources from the CVS server. (Also, unless you run configure
with the <CODE>--enable-maintainer-mode</CODE> option, the
configure script will not automatically get rebuilt when the
configure.in file is updated, so you should make sure to do that
manually when you notice configure.in has changed. One symptom
of this is finding things like @VARIABLE@ in your Makefile after
configure or config.status is run.
<P>
</DD>
<DT><B>
<a name="4.2">4.2</a> I'm having problems configuring PHP3 to work with Apache. It says
it can't find httpd.h, but it's right where I said it is!
</B></DT>
<DD>
You need to tell the configure/setup script the location of the
<EM>top-level</EM> of your Apache source tree. This means that
you want to specify '<CODE>--with-apache=/path/to/apache</CODE>'
and <EM>not</EM> '<CODE>--with-apache=/path/to/apache/src</CODE>'.
<P>
</DD>
<DT><B>
<a name="4.3">4.3</a> When I run configure, it says that it can't find the include files or
library for GD, gdbm, or some other package!
</B></DT>
<DD>
You can make the configure script looks for header files and libraries
in non-standard locations by specifying additional flags to pass to
the C preprocessor and linker, such as:
<FONT FACE="monospaced"><PRE>
CPPFLAGS=-I/path/to/include LDFLAGS=-L/path/to/library ./configure
</PRE></FONT>
If you're using a csh-variant for your login shell (why?), it would be:
<FONT FACE="monospaced"><PRE>
env CPPFLAGS=-I/path/to/include LDFLAGS=-L/path/to/library ./configure
</PRE></FONT>
<P>
</DD>
<DT><B>
<a name="4.4">4.4</a> When it is compiling the file language-parser.tab.c, it gives me errors
that say 'yytname undeclared'.
</B></DT>
<DD>
You need to update your version of Bison. You can find the latest version
at <A href="ftp://prep.ai.mit.edu/pub/gnu/">ftp://prep.ai.mit.edu/pub/gnu/</A>.
<P>
</DD>
<DT><B>
<a name="4.5">4.5</a> When I run 'make', it seems to run fine but then fails when it
tries to link the final application complaining that it can't find
some files.
</B></DT>
<DD>
Some old versions of make that don't correctly put the compiled
versions of the files in the functions directory into that same
directory. Try running "<CODE>cp *.o functions</CODE>" and then
re-running 'make' to see if that helps. If it does, you should really
upgrade to a recent version of GNU make.
<P>
</DD>
<DT><B>
<a name="4.6">4.6</a> When linking PHP3, it complains about a number of undefined references.
</B></DT>
<DD>
Take a look at the link line and make sure that all of the appropriate
libraries are being included at the end. Common ones that you might have
missed are '-ldl' and any libraries required for any database support
you included.
<P>
If you're linking with Apache 1.2.x, did you remember to add the
appropriate information to the EXTRA_LIBS line of the Configuration
file and re-rerun Apache's Configure script? See the <A href="http://ca.php.net/cvsweb.cgi/INSTALL?rev=1.18">INSTALL</A> file that
comes with the distribution for more information.
<P>
Some people have also reported that they had to add '-ldl' immediately
following 'libphp3.a' when linking with Apache.
<P>
</DD>
<DT><B>
<a name="4.7">4.7</a> I can't figure out how to build PHP3 with Apache 1.3.
</B></DT>
<DD>
<P>This is actually quite easy. Follow these steps carefully:
<UL>
<LI>Grab the latest Apache 1.3 distribution from <A href="http://www.apache.org/dist/">www.apache.org</A>.
<LI>Ungzip and untar it somewhere, for example /usr/local/src/apache-1.3.
<LI>Compile PHP3 by first running ./configure --with-apache=/<i>&lt;path&gt;</i>/apache-1.3 (substitute <i>&lt;path&gt;</i> for the actual path to your apache-1.3 directory.
<LI>Type 'make' followed by 'make install' to build PHP3 and copy the
necessary files to the Apache distribution tree.
<LI>Change directories into to your /<i>&lt;path&gt;</i>/apache-1.3/src directory and edit the <i>Configuration</i> file. At the end of the file, add: <tt>AddModule modules/php3/libphp3.a</tt>.
<LI>Type: './Configure' followed by 'make'.
<LI>You should now have a PHP3-enabled httpd binary!
</UL>
<b>Note:</b> You can also use the new Apache ./configure script. See the instructions in the README.configure file
which is part of your Apache distribution. Also have a look at the INSTALL file in the PHP distribution.
<P>
</DD>
<DT><B>
<a name="4.8">4.8</a> I have followed all the steps to install the Apache module version on UNIX, and my
PHP scripts show up in my browser or I am being asked to save the file. Help!
</B></DT>
<DD>
<P>This means that the PHP module is not getting invoked for some reason. Three things to check before
asking for further help:
<UL>
<LI> Make sure that the httpd binary you are running is the actual new httpd binary you just built. To do this,
try running: <i>/path/to/binary/httpd -l</i><br>
If you don't see <b>mod_php3.c</b> listed then you are not running the right binary. Find and install the correct binary.
<LI> Make sure you have added the correct Mime Type to one of your Apache .conf files. It should be: <b><i>AddType application/x-httpd-php3 .php3</i></b><br>
Also make sure that this AddType line is not hidden away inside a &lt;Virtualhost&gt; or &lt;Directory&gt; block which would
prevent it from applying to the location of your test script.
<LI> Finally, the default location of the Apache configuration files changed between Apache 1.2 and Apache 1.3. You
should check to make sure that the configuration file you are adding the AddType line to is actually being read. You can put an obvious syntax error into your httpd.conf file or some other obvious change that will tell you if the file is being read correctly.
</UL>
<P>
</DD>
<DT><B>
<a name="4.9">4.9</a> It says to use: --activate-module=src/modules/php3/libphp3.a, but that file
doesn't exist, so I changed it to --activate-module=src/modules/php3/libmodphp3.a and it doesn't work!?
What's going on?
</B></DT>
<DD>
Well, you decided to try to outsmart the people who wrote those nice step-by-step instructions for you and you
have now discovered that these people cannot be outsmarted. The libphp3.a file is not supposed to
exist. The Apache build process will create it.<P>
</DD>
</DL>
<HR noshade>
<A NAME="5">
<H2>5. Using PHP3</H2>
</A>
<DL>
<DT><B>
<a name="5.1">5.1</a> I would like to write a generic PHP script that can handle data coming
from any form. How do I know which POST method variables are available?
</B></DT>
<DD>
Make sure that the <i>track_vars</i> feature is enabled in your php3.ini file. If you
compiled PHP with &quot;--enable-track-vars&quot; it will be on by default.
Alternatively you can enable it at run-time on a per-script basis by putting
&lt;?php_track_vars?&gt; at the top of your file.
When <i>track_vars</i> is on, it creates three associative arrays. $HTTP_GET_VARS, $HTTP_POST_VARS
and $HTTP_COOKIE_VARS. So, to write a generic script to handle POST
method variables you would need something similar to the following:<PRE>
while (list($var, $value) = each($HTTP_POST_VARS)) {
echo "$var = $value&lt;br&gt;\n";
}</PRE>
<P>
</DD>
<DT><B>
<a name="5.2">5.2</a> I need to convert all single-quotes (') to a backslash followed by
a single-quote. How can I do this with a regular expression?
</B></DT>
<DD>
First off, take a look at the <A href="manual/function.addslashes.php3">addslashes()</A> function. It will do
exactly what you want. You should also have a look at the magic_quotes_gpc directive in your php3.ini
file.
<P>
The ereg_replace magic you're looking for, however, is simply:<PRE>
$escaped = ereg_replace(&quot;'&quot;, &quot;\\'&quot;, $input);</PRE>
<P>
</DD>
<DT><B>
<a name="5.3">5.3</a> When I do the following, the output is printed in the wrong order:<PRE>
function myfunc($argument) {
echo $myfunc + 10;
}
$variable = 10;
echo "myfunc($variable) = " . myfunc($variable);
</PRE>
<P>What's going on?
</B></DT>
<DD>
To be able to use the results of your function in an expression (such
as concatenating it with other strings in the example above), you need
to <B>return</B> the value, not echo it.
<P>
</DD>
<DT><B>
<a name="5.4">5.4</a> Hey, what happened to my newlines in:
<PRE>
&lt;PRE&gt;
1 &lt;?echo $result[1];?&gt;
2 &lt;?echo $result[2];?&gt;
</PRE>
</B></DT>
<DD>
In PHP, the ending for a block of code is either "?&gt;" <B>or</B>
"?&gt;\n" (where \n means a newline). This means that you need to
insert an extra newline after each block of PHP code in the above
example.
<P>
Why does PHP do this? Because when formatting normal HTML, this
usually makes your life easier because you don't want that newline,
but you'd have to create extremely long lines or otherwise make the
raw page source unreadable to achieve that effect.
<P>
</DD>
<DT><B>
<a name="5.5">5.5</a> I need to access information in the request header directly. How can
I do this?
</B></DT>
<DD>
The getallheaders() function will do this if you are running PHP as a
module. So, the following bit of code will show you all the request
headers:<PRE>
$headers = getallheaders();
for(reset($headers); $key = key($headers); next($headers)) {
echo "headers[$key] = ".$headers[$key]."&lt;br&gt;\n";
}
</PRE>
<P>
</DD>
<DT><B>
<a name="5.6">5.6</a> When I try to use authentication with IIS I get 'No Input file specified'
</B></DT>
<DD>
The security model of IIS is at fault here. This is a problem
common to all CGI programs running under IIS. A workaround is
to create a plain HTML file (not parsed by php) as the entry page
into an authenticated directory. Then use a META tag to redirect
to the PHP page, or have a link to the PHP page. PHP will
then recognize the authentication correctly. When the ISAPI
module is ready, this will no longer be a problem. This should
not effect other NT web servers. For more information, see: <A
href="http://support.microsoft.com/support/kb/articles/q160/4/22.asp"
target="_new">http://support.microsoft.com/support/kb/articles/q160/4/22.asp</A>.
<P>
</DD>
<DT><B>
<a name="5.7">5.7</a> I've followed all the instructions, but still can't get PHP and IIS
to work together!
</B></DT>
<DD>
Make sure any user who needs to run a PHP script has the rights
to run php.exe! IIS uses an anonymous user which is added at the
time IIS is installed. This user needs rights to php.exe. Also,
any authenticated user will also need rights to execute php.exe. And
for IIS4 you need to tell it that PHP is a script engine.
<P>
</DD>
<DT><B>
<a name="5.8">5.8</a> My PHP script works on IE and Lynx, but on Netscape some of my output
is missing. When I do a &quot;View Source&quot; I see the content in IE but not in Netscape.
Even when I telnet to port 80 directly the correct content shows up. How can this be? PHP
is server-side and my browser can't possibly know that the content it is seeing is generated
by PHP, so what is going on?
</B></DT>
<DD>
Very good question! ;) This is a tricky little issue and it has come up twice in the
past month as of this writing. Both times I ended up spending a good 20 minutes trying to
figure out what the heck was going on. The answer is that both IE and Lynx ignore any NULs
(\0) in the HTML stream. Netscape does not. The best way to check for this is to compile
the command-line version of PHP (also known as the CGI version) and run your script from the
command line and pipe it through 'od -c' and look for any \0 characters. (If you are on
Windows you need to find an editor or some other program that lets you look at binary files)
When Netscape sees a NUL in a file it will typically not output anything else on that line
whereas both IE and Lynx will. If this issue has bitten you, congratulations! You are not
alone.
<P>
</DD>
<DT><B>
<a name="5.9">5.9</a> How do I get all the results from a SELECT MULTIPLE HTML tag?
</B></DT>
<DD>
The SELECT MULTIPLE tag in an HTML construct allows users to select multiple items from a list.
These items are then passed to the action handler for the form. The problem is that they are
all passed with the same widget name. ie.
<PRE> &lt;SELECT NAME="var" MULTIPLE&gt;</PRE>
Each selected option will arrive at the action handler as:
<PRE> var=option1
var=option2
var=option3</PRE>
Each option will overwrite the contents of the previous $var variable. The solution is to use PHP's
non-indexed array feature. The following should be used:
<PRE> &lt;SELECT NAME="var[]" MULTIPLE&gt;</PRE>
This tells PHP to treat <i>var</i> as an array and each assignment of a value to var[] adds an item to
the array. The first item becomes $var[0], the next $var[1], etc. The count() function can be used to
determine how many options were selected, and the sort() function can be used to sort the option
array if necessary.<P>
Note that if you are using JavaScript the <i>[]</i> on the element name might cause you problems when you
try to refer to the element by name. Use it's numerical form element id instead.
<P>
</DD>
</DL>
<HR noshade>
<A NAME="6">
<H2>6. New Features</H2>
</A>
<DL>
<DT><B>
<a name="6.1">6.1</a> I saw PHP3 offers persistent database connections. What does that mean?
</B></DT>
<DD>
Persistent connections are SQL links that do not close when the
execution of your script ends. When a persistent connection is
requested, PHP checks if there's already an identical persistent
connection (that remained open from earlier) - and if it exists, it
uses it. If it does not exist, it creates the link. An 'identical'
connection is a connection that was opened to the same host, with
the same username and the same password (where applicable).
<P>People who aren't thoroughly familiar with the way web servers
work and distribute the load may mistake persistent connects for what
they're not. In particular, they do <B>not</B> give you an ability
to open 'user sessions' on the same SQL link, they do <B>not</B>
give you an ability to build up a transaction efficently, and they
don't do a whole lot of other things. In fact, to be extremely
clear about the subject, persistent connections don't give you <B>any</B>
functionality that wasn't possible with their non-persistent brothers.
<P>Why?
<P>This has to do with the way web servers work. There are three ways
in which your web server can utilize PHP to generate web pages.
<P>The first method is to use PHP as a CGI "wrapper". When run this
way, an instance of the PHP interpreter is created and destroyed for
every page request (for a PHP page) to your web server. Because it
is destroyed after every request, any resources that it acquires (such
as a link to an SQL database server) are closed when it is destroyed.
In this case, you do not gain anything from trying to use persistent
connections -- they simply don't persist.
<P>The second, and most popular, method is to run PHP as a module
in a <I>multiprocess</I> web server, which currently only includes
Apache. A multiprocess server typically has one process (the parent)
which coordinates a set of processes (its children) who actually do
the work of serving up web pages. When each request comes in from a a
client, it is handed off to one of the children that is not already
serving another client. This means that when the same client makes
a second request to the server, it may be serviced by a different
child process than the first time. What a persistent connection does
for you in this case it make it so each child process only needs
to connect to your SQL server the first time that it serves a page
that makes us of such a connection. When another page then requires
a connection to the SQL server, it can reuse the connection that
child established earlier.
<P>The last method is to use PHP as a plug-in for a <I>multithreaded</I>
web server. Currently this is only theoretical -- PHP does not
yet work as a plug-in for any multithreaded web servers. Work is
progressing on support for ISAPI, WSAPI, and NSAPI (on Windows),
which will all allow PHP to be used as a plug-in on multithreaded
servers like Netscape FastTrack, Microsoft's Internet Information
Server (IIS), and O'Reilly's WebSite Pro. When this happens, the
behavior will be essentially the same as for the multiprocess model
described before.
<P>If persistent connections don't have any added functionality,
what are they good for?
<P>The answer here is extremely simple -- efficiency. Persistent
connections are good if the overhead to create a link to your SQL
server is high. Whether or not this overhead is really high depends
on many factors. Like, what kind of database it is, whether or
not it sits on the same computer on which your web server sits,
how loaded the machine the SQL server sits on is and so forth.
The bottom line is that if that connection overhead is high,
persistent connections help you considerably. They cause the child
process to simply connect only once for its entire lifespan, instead
of every time it processes a page that requires connecting to the
SQL server. This means that for every child that opened a persistent
connection will have its own open persistent connection to the server.
For example, if you had 20 different child processes that ran a script
that made a persistent connection to your SQL server, you'd have 20
different connections to the SQL server, one from each child.
<P>An important summary. Persistent connections were designed to
have one-to-one mapping to regular connections. That means that you
should <B>always</B> be able to replace persistent connections with
non-persistent connections, and it won't change the way your script
behaves. It <B>may</B> (and probably will) change the efficiency
of the script, but not its behavior!
<P>
</DD>
</DL>
<HR noshade>
<A NAME="7">
<H2>7. Common Problems</H2>
</A>
<DL>
<DT><b>
<a name="7.1">7.1</a> I installed PHP3, but every time I load a document, I get the
message 'Document Contains No Data'! What's going on here?
</b></DT>
<DD>
This probably means that PHP3 is having some sort of problem
and is core-dumping. Look in your server error log to see if
this is the case, and then try to reproduce the problem with
a small test case. If you know how to use 'gdb', it is very
helpful when you can provide a backtrace with your bug report
to help the developers pinpoint the problem. If you are using
PHP as an Apache module try something like:
<ul>
<li> Stop your httpd processes
<li> gdb httpd
<li> &gt; run -X -f /path/to/httpd.conf
<li> Then fetch the URL causing the problem with your browser
<li> If you are getting a core dump, gdb should inform you of this now
<li> type: bt
<li> Send the resulting backtrace to <a href="mailto: php-dev@lists.php.net">php-dev@lists.php.net</a>
</ul>
<P>
If your script uses the regular expression functions (<CODE>ereg()</CODE>
and friends), you should make sure that you compiled PHP3 and
Apache with the same regular expression package. (This should
happen automatically with PHP3 and Apache 1.3.x)
<P>
</DD>
<DT><B>
<a name="7.2">7.2</a> I'm trying to access one of the standard CGI variables (such
as $DOCUMENT_ROOT or $HTTP_REFERER) in a user-defined function,
and it can't seem to find it. What's wrong?
</B></DT>
<DD>
Environment variables are now normal global variables, so you must
either declare them as global variables in your function (by using
"<CODE>global $DOCUMENT_ROOT;</CODE>", for example) or by using
the global variable array (ie, "<CODE>$GLOBALS["DOCUMENT_ROOT"]</CODE>".
<P>
</DD>
<DT><B>
<a name="7.3">7.3</a> I patched Apache with the FrontPage extensions patch, and suddenly PHP stopped
working. Is PHP incompatible with the Apache FrontPage extensions?
</B></DT>
<DD>
No, PHP works fine with the FrontPage extensions.
The problem is that the FrontPage patch modifies several Apache structures,
that PHP relies on.
Recompiling PHP (using 'make clean ; make') after the FP patch is applied
would solve the problem.
<P>
</DD>
<DT><B>
<a name="7.4">7.4</a> I think I found a bug! Who should I tell?
</B></DT>
<DD>
You should go to the PHP Bug Database and make sure the bug
isn't a known bug. If you don't see it in the database, use
the reporting form to report the bug. It is important to use
the bug database instead of just sending an email to one of the
mailing lists because the bug will have a tracking number assigned
and it will then be possible for you to go back later and check
on the status of the bug. The bug database can be found at <A
href="http://ca.php.net/bugs.php3">http://ca.php.net/bugs.php3</A>.
<P>
</DD>
</DL>
<HR noshade>
<A NAME="8">
<H2>8. Migrating from PHP2 to PHP3</H2>
</A>
<DL>
<DT><B>
<a name="8.1">8.1</a> When I add two strings together and then echo it, it echoes zero instead
of the concatenation of the two strings! What's going on? Wouldn't it
be great if adding two strings just concatenated them together?
</B></DT>
<DD>
PHP3 does not support the overloading of the addition operator for
strings because values that arrive via the GET and POST methods and
from databases are always stored as strings. This means that if the
plus operator were overloaded to concatenate strings, you could add
what you thought were two numbers and get the wrong result! (For
example, "4" + "5" would be equal to "45".) One way around this would
be to explicitly type-cast one or both of the operands, which is what
PHP/FI 2 did.
<P>This has been simplified in PHP3 by the addition of a real string
concatenation operator. If you want to "add" two strings together,
just write it like: <CODE>"this" . "that"</CODE> which will result in
the string "thisthat".
<P>The answer to the final part of the question is an emphatic no.
Operator overloading can be a source of great confusion, especially
when variables aren't very strongly typed to begin with, as they are
in PHP3.
<P>
</DD>
<DT><B>
<a name="8.2">8.2</a> When I use the chmod(), umask(), or mkdir() functions, the permissions
are wrong!
</B></DT>
<DD>
Unlike PHP/FI 2, PHP3 does not interpret the numeric arguments for
these functions any differently than for any other function, which
means you need to pass in an octal value if you are specifying an
octal number, such as:
<PRE>
chmod($myfile, 0600);
</PRE>
<B>not</B>
<PRE>
chmod($myfile, 600);
</PRE>
<P>
</DD>
<DT><B>
<a name="8.3">8.3</a> I converted my script from PHP/FI 2.0 to PHP3 syntax, but now it just
hangs! When I looked at the processes running on my server, there was
one process that was chewing up all of the CPU cycles!
</B></DT>
<DD>
You probably missed the semi-colon on a <CODE>while
(condition);</CODE> statement. This will cause PHP3 to spin out of
control because it is simply executing an empty body for your while
loop! Change the semi-colon to a colon and it should work correctly.
<P>
</DD>
<DT><B>
<a name="8.4">8.4</a> My user-functions don't work any more! I get a "Parse error (expecting '('"
on the first line of the function.
</B></DT>
<DD>
PHP3's function declaration now resembles C function declarations, so
your function should look like:
<PRE>
function printsum($a, $b) {
echo $a + $b;
}
</PRE>
<P>You can also use old-style function declarations by use the
'old_function' designation, like so:
<PRE>
old_function printsum $a, $b (
echo $a + $b;
);
</PRE>
<P>
</DD>
<DT><B>
<a name="8.5">8.5</a> What happened to the securevar() function that was in PHP2? How can
I make sure that a GET-method variable does not overwrite a POST-method one?
</B></DT>
<DD>
The securevar() function in PHP2 was a badly named function. It gave the impression that
when used the POST-method was secure. It is not. It is only slightly more difficult to
fake POST-method variables than GET-method ones.
<P>
There are a couple of ways to achieve similar things in PHP3. The most straightforward way is
to do it manually by using the <i>$HTTP_POST_VARS</i> array. See <a href="#5.1">FAQ question 5.1</a>
for instructions on how to enable it. To make sure that $foo, for example, comes from the POST data
and nowhere else you would do:
<PRE>
$foo = $HTTP_POST_VARS["foo"];
</PRE>
A second way to do this is to change the gpc_order setting in your php3.ini file. The default setting is
&quot;GPC&quot; which means that GET variables are parsed first followed by POST variables and lastly by
COOKIE variables. This means that GET vars are overwritten by POST vars which are in turn overwritten by
COOKIE vars. So, by default if you have the same variables in your GET and POST data the POST one will
be the one that shows up in the main PHP symbol table and you would have to use the <i>$HTTP_GET_VARS</i>
to get at it. Along with changing the order from &quot;GPC&quot; to something like &quot;CGP&quot; which
would make POST variables have the highest priority, you can leave out any of the letters to completely
disable PHP's ability to see a certain type of variable. If you never wanted GET-method data to be turned
into PHP variables you could use a gpc_order setting of &quot;PC&quot;.
<DD>
</DD>
</DL>
<HR noshade>
<H2>Credits</H2>
<P>This FAQ was originally written by Jim Winstead. It is currently
maintained by the PHP Development Team.
<P>
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