MANUAL file:///usr/share/doc/packages/php-doc/index.html
but be aware that there are HIDDEN CHAPTERS!!!
like file:///usr/share/doc/packages/php-doc/language.variables.scope.htmlma/scop

"php5 -l singlefile.php".   Does syntax (Lint) check.
IGNORES files after the first one specified!

NO try {...} finally { }!!!
Exceptions work just like Java Exceptions.  Only problem is that fatal runtime
errors don't throw anything.  Therefore, without a finally() block, fatal 
runtime errors not detected by user code can not be caught.

LIMITATION!
Undetected fatal errors on a .php web page will just croak the HTTP request.

SuSE php.ini file locations:
    php v.4 CLI:  /etc/php.ini
    php v.4 Apache module:  /etc/php.ini
    php v.5 CLI:  /etc/php5/cli/php.ini
    php v.5 Apache module:  /etc/php5/apache2/php.ini

N.b.:  Syntax errors in php.ini can cause the remainder (or all) of the
       php.ini file to be silently ignored!!  This includes commenting
       with #.

BUGS

    The PHP5 cli build is screwed up.  It insists on being verbose and
    printing HTML tags with all output.

    warn_plus_overloading setting DOES NOT WORK either from .ini file or
    by ini_set().

    error_append_string doesn't work (at least for trigger_error() calls).

Run "php -v" to see whether your php binary is the CLI (command line) or
CGI SAPI (Server API).
(The Suse php4 rpm is a CLI build, but php5 rpm is a CGI build).
*** Newest 10.0 SuSE has a good php5 cli and Apache module build, each
with good config files ***

PHP under Apache module definitely requires an Apache stop/start if php.ini
is changed.
There is only one php.ini file used by all the Apache virtual sites.

CLI features
    php -h  (for syntax)
    Basically first non-switch arg is a PHP script file name.
    *** I doubt the following.  stdin is not available until you open it.
    STDIN, STDOUT, STDERR.  Streams already made with fopen('php://stdX...);
        (Use like 'fwrite(STDERR, "stderr\n");').
    I don't know difference between echo and "fwrite(STDOUT...".
    -c option DOES NOT WORK.  Always uses /etc/php.ini.
    *** Works with newest Suse 10.0 build!! ***
    Read input (only works in real CLI mode, not like SuSE's php5 build):
        $str = fgets(STDIN);
        if ($str) $str = rtrim($str);

Arrays (really maps)
    Length:  sizeof($arr);
    Some of the docs differentiate between "numerical array keys"
     and "literal array keys".  But freaking Array section doesn't mention this.
    $aname = array('key1' => 'val1', 'key2', => 'val2');
    $aname['key1'];
    (In some special cases, real array indexes are specified like $array{2},
     but usually not.  Not documented anywhere that I can find.)
    Simulated a real array:  array(1,2,3)
       (This actually does array(0->1, 1->2, 2->3).)
       But indexes do not reset without: $array = array_values($array);
       push/add:  $arr[] = 7;
    Display with print_r($ar);
    array_shift($ar); array_push($ar); etc.
    $str = implode('delim', $ar);  // array-VALUES-to-string
    $ar = explode('delim', $str);  // String tokenizer

Objects.
    N.b. NO IMPLICIT this-> inside the Class.  I.e., you must code
        "$this->membername".
    N.b. STATICS are not preserved across requests.  I guess each class
     gets clinitted anew for each request.  I guess need to use a real
     Java singleton under JSR to preserve anything.
     (Especially since can't store "resources" in a Session").
    class X { public $var = 'x'; public function f() {...} }
    Member and function visibility specifiers:  public/private/protected.
    Members must specify visibility explicitly.  Functions default to public.
    $instance = new X();
    var_dump($instance);  # displays the object
    __autoload automatically invoked to try to load source files for 
      new classes automatically.  This tries to load "ClassName.php":
        function __autoload($class_name) { require_once $class_name . '.php'; }
    CONS
        I think can only have one constructor method, but it have default vals
         for parameters, and may call other methods (of course).
        function __construct() {
           parent::__construct();  # Note need to call super-cons explicitly.
           ...}
    CLASSNAME::member/function.  parent and self are special Class names
     available only inside the using class.  NO $!!!
        SYNTAX:  Cname::$var    AND    Cname::method()
                 Cname::$var->varmeth()
     "$this" but "self" and "parent".
     $object var  vs.  static class names.
    DEREFERENCE instance vars:  $instance->x = 'newval'; $instance->function();
     VS.  Cname::$var; Cname::method().
     [[ N.b. ONLY time you put $ on final variable/method is for static vars.
    Constants.  Keyword "const".  Do not use $ to access.  Effectively static.
    statics and constants may not be accessed through instances.
    Overriding is clumsy.  You code generic "handlers" called by all 
     function or variable accesses.

    Object Operators:  get_class() and instanceof (previously is_a()).

To make another reference to same object (as opposed to ref to var name),
use "$newref =& $origvar;"  I think this is equivalent to "obj2 = obb1;"
in Java (but not "primitive2 = primitive1;".

# comment
// comment
/* comment */
N.b. that PHP in XML comments STILL EXECUTES.  E.g.
"<!-- <? echo "This is from PHP\n"; ?>" --> will write
"<!-- This is from PHP
?>" into the HTML/output.

String quoting
    Here doc strings are just like double-quoted strings.
     (Whatever I say about double-quoted strings below applies to HD strings).
    Must use "\n", not '\n'.
    "" and '' strings may span lines.
    'string': Escape only single quotes:  \'
    "string":
        $varname, ${varname}.
        $aname[key1]  # N.b., no quotes around key!
        Must use "complex syntax" to use any inner quotes.
        $obj->member  (BUT NOT $obj->method()!!!)
        COMPLEX SYNTAX (between "${ and }", but $ is part of the expression).
            {$aname['key1']}   # Must put inside {} to use inner quotations

Strings
    str.charAt(3) in Java =>  $str{3}.
    .:  Concatenation operator  (just like perl)

USEFUL:  gettype($var);


REMAINDER OF THIS FILE IS ABOUT USING JAVA FROM PHP (mostly about
building PHP for using Java).

BUILDING php --with-java.
Run "configure --with-java=/path/to/real/java/home"  (not a sym link!).
Run "make" ignore errors.
Copy java.so to /usr/lib/php/extensions/libphp_java.so
Copy php_java.jar to /usr/lib/php.



php.ini   I don't think I ever use this stuff.
=====================================
java.class.path = /usr/lib/php/php_java.jar
java.home = /usr/lib/SunJava2-1.4.2/jre
java.library.path = /usr/lib/php/extensions
java.library = /usr/lib/SunJava2-1.4.2/jre/lib/i386/server/libjvm.so
extension=libphp_java.so
; Note many deviations from the PHP documentation and user posts!

RUNTIME
Must
export LD_LIBRARY_PATH=/usr/lib/SunJava2-1.4.2/jre/lib/i386:/usr/lib/SunJava2-1.4.2/jre/lib/i386/server

http://php.mirror.netmonic.com/manual/en/ref.java.php

CLASSES MUST BE public!!!!
Can use classes in default class.


EXTENSION DEVELOPMENT HOWTO:
Good news:  The php binary DOES NOT NEED TO BE REBUILT to use a new module!
http://www.zend.com/php/internals/extension-writing1.php?article=extension-writing1&kind=internals&id=6957&open=1&anc=0&view=1

    2nd arg to RETURN_X means 0: use/deallocate item we supplied, or
    1: copy it.  Don't need 2nd argument for primitive non-String scalars.


    I am using the Suse src bundle, understanding *possible* lack of 
    multi-thread mode testing.  I junzip the main php4*tar.bz2 tar file 
    form the php4*src*.rpm.

    Need to install php-devel, m4, automake, autoconf, libtool RPMs.

    Edit phpize.m4 and comment out the AC_PROG_LIBTOOL line with #.

    vim /usr/share/php/build/phpize.m4
    comment out #AC_PROG_LIBTOOL

    vim /usr/bin/phpize
    Change "$libtoolize -f -c || exit 1" to "$libtoolize   || exit 1".
    ln -s ../../config.sub
    ln -s ../../config.guess
    Ignore warnings about hello.la ?
    Edit Makefile and change "LIBTOOL=" to "LIBTOOL=/usr/bin/libtool"

757 -630 1523


VARIABLE SCOPE
Generall available in current scope and below.
Exception is functions, which have local variables and do not have
access to higher-level variables, except for "super global" variables.
Can use "global $vname;" to access a normal global in a function.
static vars are static within a function, and initializers only run once.
I don't know how to define a global or super global in a web app.  See
file:///usr/share/doc/packages/php-doc/language.variables.scope.htmlma/scop
[UNTRUE:
Funny thing is, normal globals are still scoped.  I.e., only globals defined
in the global CALLING scope are visible inside functions.  Not globals 
defined inside the function source file.
No idea why it looks like this in module functions sometimes.
]

PREDEFINED CONSTANTS
file:///usr/share/doc/packages/php-doc/reserved.constants.html
(incl. preset variables, see phpinfo()).


NULL == UNDEFINED (but you'll get warnings for reading undefined vars).
isset(), is_null()
It is an error to "read" an "undefined" variable, so run
    if (!isset($varname)) $varname = null;
for variables which may or may not be set.

Reading/writing files.  use the f*() functions.  See my sample
filewriter.php script.

Logging.  the log() functions are for mathematical logarithms, not logging.
The only way to use logging "levels" is with trigger_error(), (a.o.t.
error_log()).  Yet, trigger_errors above a certain level (E_USER_ERROR)
automatically abort/exit execution!
See the EXITING section below too!
Be aware that a limitation of declarative setup is that with mod_apache,
there's only one php.ini file for the entire Apache instance.
SIMPLEST
    error_log("message\n", 3, "file/path.log");
    error_log messages always and only get error_log-logged.
                  NEVER GET DISPLAYED, only triggered errors can.
    Not smart enough to append a newline to log entries.
DECLARATIVE SETUP:  php.ini / ini_set().  Default values shown.
    display_errors = On   # Whether to "display" triggered errors.
    log_errors = Off      # Whether to "error_log" triggered errors.
    html_errors = On      # Format (only) of display_errors output,
                          #  (uses docref_* settings for links)
    error_reporting = ??? E_ALL & ~E_NOTICE    # Logging levels.
                          # Defaults documented and seen differ.
    track_errors = Off    # Maintain $php_errormsg (which is scoped).
    error_log = [no dflt] # Destination if log_errors on.
    error_log = "syslog"  # Works great.  How to send to stdout/stderr???
    error_log = "/path/to/log.txt"  # I think must be absolute
    warn_plus_overloading = ?  # About "string" + "string"  DOES NOT WORK!!!!
    display_startup_errors = Off  # I'm only documenting in order to say
                               # that they recommend to leave it off.
DECLARATIVE USE:
    For logging levels, see 
file:///usr/share/doc/packages/php-doc/ref.errorfunc.html#errorfunc.constants
    The triggered errors 
    trigger_error("message", E_USER_ERROR); // may only set a level of:
        E_USER_ERROR, E_USER_WARNING, E_USER_NOTICE.
    trigger_error("message");  // Uses default level of E_USER_NOTICE.
    Triggered messages go to display and/or error_log depd on those settings.
    trigger_error() always logs the level.
    error_log("message");      // Note that the type (not lvl) defaults to 0.
                               // Does not log any level.
    error_log messages always and only get error_log-logged.
                  NEVER GET DISPLAYED, only triggered errors can.

NO WAY TO
    Log a stack trace at will.  Can only "display" it (which us usually
     not possible).
    Get a warning or error for use of undefined constants.
    Get a warning or error for an undeclared variable.
     (but do get warning for a TEST of an undeclared variable)

IMMENSELY USEFUL
    $_SERVER['PHP_SELF'] is the page REQUESTED, I think it's probably
    the entire path after the hostname (and port), but could possibly
    be relative to the context root under jsr223.  Begins with /.
    __FILE__, __LINE__, __FUNCTION__, __CLASS__, __METHOD__
    absolute identification of exactly what is running exactly here in code.

Length of a string: strlen().

include/require
    Filepath may be any of
        ^./:  Relative to $PWD.  include_path ignored.
        ^/:   Absolute path.  include_path ignored.
        OTHER:  Relative to include_path elements (like $CLASSPATH or $PATH)

URL ENCODING
    Regardless of language, you can never encode the (desired) query string 
    delimiters.
    I REALLY HAVE NO WAY OF KNOWING whether Browser is changing the query
    string in between a redirect.
    Regardless of whether GET Query Strings have VALUES encoded or not, the
    values in $_GET are always de-coded, and the values in $QUERY_STRING
    are always encoded (the latter besides the ? and & delimites, of course).
    I.e., if you forward via 'header("Location: URL");', it doesn't matter
     if you encode values, other than escaping ? and &.  (UNLESS MY BROWSER
     IS ENCODING FOR ME.  Can find out with tcpdump.)

HTTP HEADERS:  Really userful.
// Date in the past
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
// always modified
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT");
// HTTP/1.1
header("Cache-Control: no-store, no-cache, must-revalidate");
header("Cache-Control: post-check=0, pre-check=0", false);
// HTTP/1.0
header("Pragma: no-cache");
header("Location: http://" . $_SERVER['HTTP_HOST']
      . dirname($_SERVER['PHP_SELF']) . "/" . $relative_url);

SESSIONS
session_id() returns '' (not null or false!) if no session_start() called yet.
session_start() will create or regenerate a session, but it bitches if it has
already been called for this request.  Therefore, if not top-level page, call
    if (session_id() == '') session_start();

DATABASE
  The ODBC extension is very limiting wrt prepared statement reuse/params.
  PDO ODBC extension is powerful but buggy.  Segmentation faults with null
  values, columns over a couple hundred bytes, etc.

EXITING
    Exits, whether from exit() or trigger_error(), will generate a HTTP
    error IF < 2 CHARACTERS HAVE BEEN WRITTEN.  Otherwise the page
    written so far will be returned with HTTP success status.
    Must have at least like "x " (i.e., not whitespace + whitespace) before
    the "<?php".
    Exits write nothing to the configured log or stderr.
    ARRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRG!!!!!!!!!!
    I can not tell how PHP decides when to send a HTTP 500.
    The same page with the same inputs sends a success and a 500 based on if
    it was called with an Ajax POST or a normal form POST.
    Could be some option to prototypejs, but I see nothing.