Programming PHP

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Example 7-13. Setting preferences with sessions (continued) session_start(); session_register('bg'); session_register('fg'); $bg_name = $_POST['background']; $fg_name = $_POST['foreground']; $bg = $colors[$bg_name]; $fg = $colors[$fg_name]; ?> Example 7-14 shows Example 7-12 rewritten to use sessions. Once the session is started, the $bg and $fg variables are created, and all the script has to do is use them. Example 7-14. Using preferences from sessions Front Door
Custom storage By default, PHP stores session information in files in your server’s temporary directory. Each session’s variables are stored in a separate file. Every variable is serialized into the file in a proprietary format. You can change all of these things in the php.ini file. You can change the location of the session files by setting the session.save_path value in php.ini. If you are on a shared server with your own installation of PHP, set the directory to somewhere in your own directory tree, so other users on the same machine cannot access your session files. PHP can store session information in one of two formats in the current session store—either PHP’s built-in format, or WDDX (http://www.wddx.org). You can change the format by setting the session.serialize_handler value in your php.ini file to either php for the default behavior, or wddx for WDDX format. You can write your own functions for reading and writing the registered variables. In this section, we’ll develop an example that stores session data in a database, which lets you share sessions between multiple sites. It’s easy to install your custom session store. First, set session.save_handler to user in your php.ini file. Next, write functions for opening a new session, closing a session, reading session information, writing session information, destroying a session, and cleaning up after a session. Then register them with the session_set_save_handler() function: session_set_save_handler(open_fn, close_fn, read_fn, write_fn, destroy_fn, gc_fn); To make all the PHP files within a directory use your custom session store, set the following options in your httpd.conf file: php_value session.save_handler user php_value session.save_path mydb php_value session.name session_store The mydb value should be replaced with the name of the database containing the table. It is used by the custom session store to find the database. The following sample code uses a MySQL database for a session store (databases are discussed in full in Chapter 8). The table used in the example has the following structure: CREATE TABLE session_store ( session_id char(32) not null PRIMARY KEY, expiration timestamp, value text not null ); The first function you must provide is the open handler, which takes care of opening a new session. It is called with the current value of session.save_path (from your This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved. Maintaining State | 185
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Programming PHP
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Programming PHP by Rasmus Lerdorf a
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Colophon Our look is the result of
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Accessing Individual Characters 79
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Concealing PHP Libraries 293 PHP Co
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clarify the explanations, and the p
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There is a web page for this book,
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Chapter 2 CHAPTER 2 Language Basics
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Comments Comments give information
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*/ echo("l=$l m=$m n=$n\n"); ?> Now
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change. Constants are referred to b
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PHP recognizes floating-point numbe
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• The empty string ("") and the s
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Chapter 6 describes classes and obj
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The old value of $black is lost. In
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update_counter( ); update_counter(
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Table 2-3. PHP operators P A Operat
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The division and multiplication ope
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Autoincrement and Autodecrement Ope
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Bitwise Operators The bitwise opera
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something is true. For example, you
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Because all operators are required
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if The if statement checks the trut
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A switch statement is given an expr
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if ($i == 5) break; // breaks out o
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This program adds the numbers from
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loops, and complain if the file bei
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XML Style Because of the advent of
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and other such niceties. Some will
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Chapter 3 CHAPTER 3 Functions A fun
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Typically, functions return some va
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As we discussed in Chapter 2, the e
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Example 3-5. Doubler redux function
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Missing Parameters PHP lets you be
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Anonymous Functions Some PHP functi
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echo "$who was $where"; Kilroy was
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As a special case, you can put a se
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• A padding specifier denoting th
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Boolean values and NULL are not mea
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Changing Case PHP has several funct
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The quote_style and charset argumen
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Query-string encoding The urlencode
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The comparison operators (=) also w
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The Levenshtein algorithm calculate
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The str_repeat( ) function takes a
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print_r($a);Array ( [0] => Fred [1]
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The c in strcspn( ) stands for comp
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These three kinds of patterns can b
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Subpatterns You can use parentheses
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Table 4-8. POSIX anchors Anchor Mat
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Example 4-1. Credit-card validator
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Character Classes Perl-style regula
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Trailing Options Perl-style regular
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A simple use of positive lookahead
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For example: preg_match('/y.*e$/',
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Pass an array of strings as subject
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Quoting for regular expressions The
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Identifying Elements of an Array Yo
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array is almost always a programmer
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Two or more consecutive commas in t
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echo "true!\n"; } if (array_key_exi
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EXTR_PREFIX_SAME, which says that t
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echo "$key is $value\n"; } 0 is spa
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The default argument, if provided,
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you need to answer questions like
Page 133 and 134: Example 5-3. Sorting arrays (contin
Page 135 and 136: Here’s how to randomize the order
Page 137 and 138: Sets Arrays let you implement the b
Page 139 and 140: Here’s the output from Example 5-
Page 141 and 142: Terminology Everyobject-oriented la
Page 143 and 144: You can use variable variables with
Page 145 and 146: } function set_name ($new_name) { $
Page 147 and 148: The object created bythe Person con
Page 149 and 150: Example 6-1. Displaying all declare
Page 151 and 152: Example 6-2. Object introspection f
Page 153 and 154: Here are some sample classes and ob
Page 155 and 156: PHP has two hooks for objects durin
Page 157 and 158: Example 6-5 shows the file next.php
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Page 161 and 162: SERVER_NAME The hostname, DNS alias
Page 163 and 164: The biggest difference between GET
Page 165 and 166: Figure 7-1. The chunkify form and i
Page 167 and 168: Example 7-4. Temperature conversion
Page 169 and 170: Example 7-6. Multiple selection val
Page 171 and 172: Example 7-8. Sticky multivalued che
Page 173 and 174: Files are stored in the server’s
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Page 179 and 180: A third technique for maintaining s
Page 181 and 182: Example 7-10. Preference selection
Page 183: Session basics To enable sessions f
Page 187 and 188: When a session is completed, the de
Page 189 and 190: Chapter 8 CHAPTER 8 Databases PHP h
Page 191 and 192: columns, each of which has a name a
Page 193 and 194: Figure 8-1. The movie page the data
Page 195 and 196: $db = DB::connect($datasource); if
Page 197 and 198: string(4) "1962" ["name"]=> string(
Page 199 and 200: The executeMultiple( ) method takes
Page 201 and 202: echo "$k"; if (is_array($v)) { a_to
Page 203 and 204: Two HTML forms are needed to popula
Page 205 and 206: Example 8-3. Database connection ab
Page 207 and 208: Example 8-4. Backend administration
Page 209 and 210: Example 8-5. Adding a business (con
Page 211 and 212: Example 8-5. Adding a business (con
Page 213 and 214: The business listings page is illus
Page 215 and 216: The series of requests sent by the
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Page 221 and 222: Example 9-4. Adding text to an imag
Page 223 and 224: Example 9-6. Displaying vertical Tr
Page 225 and 226: Example 9-8. Caching dynamic button
Page 227 and 228: You can also take this a step furth
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Page 231 and 232: True Color Color Indexes The color
Page 233 and 234: Chapter 10 CHAPTER 10 PDF Adobe’s
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Figure 10-1. Hello world in a PDF d
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Type, Content-Disposition, and Cont
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Example 10-3. Changing the origin (
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Example 10-4. Text alignment within
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Example 10-5. Changing text attribu
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usr/share/fonts FontAFM LuciduxSans
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Adding an image to a PDF document i
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Example 10-8. Nonproportional scali
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Figure 10-9. A sample path The pdf_
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The width and height parameters spe
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Example 10-11. Using a template Th
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Example 10-12. Using bookmarks and
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Example 10-13. Specifying a link (c
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Figure 10-16. Closed note The conte
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In HTML, you often have an open tag
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Example 11-1. Generating an XML doc
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The end element handler is called w
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If your external entity reference h
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characters outside the target encod
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XML_ERROR_BAD_CHAR_REF XML_ERROR_BI
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Figure 11-2. Book details comment).
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Example 11-10. bookparse.xml (conti
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Example 11-12. News XSL transform
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more information). The xmlrpc exten
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equest, but it doesn’t know how t
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Chapter 12 CHAPTER 12 Security PHP
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These directives ensure that PHP er
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Restrict Filesystem Access to a Spe
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function or PHP’s copy( ) functio
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• Any system call (through functi
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You can globally disable particular
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Chapter 13 CHAPTER 13 Application T
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user.template. It uses the {DESTINA
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{ARTICLE} might be useful, as it wo
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} ob_start('rewrite'); ?> Visit our
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To turn off error reporting entirel
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Example 13-5. Log-rolling error han
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Before you begin optimization, ask
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changes you make to your code as yo
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• Only include or require files t
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MySQL replication Sometimes the dat
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Chapter 14 CHAPTER 14 Extending PHP
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examples, and you are strongly enco
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int Integer/long long Same as int a
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zend_module_entry rot13_module_entr
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for(i=0, ch=arg; i= 'A')&&(*ch
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if (extension_loaded($module)) { $s
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SWF_DIR=$i AC_MSG_RESULT(found in $
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If you compile the Apache module ve
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For example: zval **old, *new; *new
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The value returned from a PHP funct
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A More Complex Example Here’s an
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Table 14-4. RETURN-related convenie
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* ... */ }; PHP_MINIT_FUNCTION(foo)
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using SEPARATE_ZVAL( ), initializes
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The struct looks like this in the p
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zend_hash_update(&EG(symbol_table),
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Resources A resource is a generic d
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Chapter 15 CHAPTER 15 PHP on Window
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3. Windows 95/98/Me: the Windows sy
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Then explicitly load the module wit
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un under IIS, you will need to reim
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External Commands PHP uses the defa
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This creates a reference (VT_BYREF)
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Figure 15-3. Gleaning syntax from W
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Now we can complete the invoice wit
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multiple Workbooks, each of which c
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Example 15-4. Querying Excel via OD
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• Applications that want to use t
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Example 15-5. Add new phone number,
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Files, directories, and filesystem
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addcslashes string addcslashes(stri
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array_merge array array_merge(array
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array_search mixed array_search(mix
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asort void asort(array array[, int
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call_user_func mixed call_user_func
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chown bool chown(string path, mixed
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cos double cos(double value) Return
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Any characters in the format string
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each array each(array array) Create
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Any number of these options can be
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fflush int fflush(int handle) Commi
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filemtime int filemtime(string path
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If include is specified and is true
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ftell int ftell(int handle) Returns
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get_current_user string get_current
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get_parent_class string get_parent_
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getmypid int getmypid( ) Returns th
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header void header(string header[,
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implode string implode(array string
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is_double bool is_double(mixed valu
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is_scalar bool is_scalar(mixed valu
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Calculates the Levenshtein distance
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log double log(double number) Retur
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mkdir int mkdir(string path, int mo
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number_format string number_format(
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openlog int openlog(string identity
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parse_url array parse_url(string ur
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phpinfo void phpinfo([int what]) Ou
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printf int printf(string format[, m
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eaddir string readdir(int handle) R
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ound double round(double number[, i
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setlocale string setlocale(mixed ca
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sort void sort(array array[, int fl
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str_pad string str_pad(string strin
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%H Hour in 24-hour format, includin
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strncmp int strncmp(string one, str
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strtr string strtr(string string, s
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tmpfile int tmpfile( ) Creates a te
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unregister_tick_function void unreg
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wordwrap string wordwrap(string str
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old versions of aspell, you should
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DBM For very simple database instal
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Hyperwave Hyperwave is a database f
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mcrypt This extension provides an i
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pdflib pdflib provides support for
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Sybase This extension provides supp
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Symbols & (ampersand) &= (bitwise A
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| (vertical bar) |= (bitwise OR ass
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aspell PHP library, 457 assert() fu
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checksums mhash library, 464 valida
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cryptography mcrypt extension, 464
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DTD (Document Type Definition), 263
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System V Semaphores and Shared memo
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calling, 61 for each array element,
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H hash mark (#) in comments, 19 hea
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interlacing GIF images, 246 interna
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masks, using in string searches, 94
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serialization of, 153-157, 438 _ _s
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pdf_open_file() function, 234 pdf_p
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with echo, 76 with print() function
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S Sablotron C library (XSLT support
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sql_regcase() function, 443 sqrt()
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tan() function, 451 target encoding
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function parameters, 33 functions f
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xml_set_unparsed_entity_decl_handle
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