Programming PHP

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guess. Also, there are features of the xmlrpc extension we haven’t covered, such as SOAP faults. See the xmlrpc extension’s documentation at http://www.php.net for the full details. For more information on XML-RPC, see Programming Web Services in XML-RPC, by Simon St. Laurent, et al. (O’Reilly). See Programming Web Services with SOAP, by James Snell, et al. (O’Reilly), for more information on SOAP. 284 | Chapter 11: XML This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved.
Chapter 12 CHAPTER 12 Security PHP is a flexible language that has hooks into just about every API offered on the machines on which it runs.Because it was designed to be a forms-processing language for HTML pages, PHP makes it easy to use form data sent to a script.Convenience is a double-edged sword, however.The very features that let you quickly write programs in PHP can open doors for those who would break into your systems. It’s important to understand that PHP itself is neither secure nor insecure.The security of your web applications is entirely determined by the code you write.For example, take a script that opens a file whose name was passed as a form parameter.If you don’t check the filename, the user can give a URL, an absolute pathname, or even a relative path to back out of the application data directory and into a personal or system directory. This chapter looks at several common issues that can lead to insecure scripts, such as filenames, file uploads, and the eval( ) function.Some problems are solved through code (e.g., checking filenames before opening them), while others are solved through changing PHP’s configuration (e.g., to permit access only to files in a particular directory). Global Variables and Form Data One of the most fundamental things to consider when creating a secure system is that any information you didn’t generate within the system should be regarded as tainted.You should either untaint this data before using it—that is, ensure that there’s nothing malicious in it—or limit what you do with it. In PHP, however, it’s not always easy to tell whether a variable is tainted.When register_globals is enabled in the php.ini file, PHP automatically creates variables from form parameters and cookies.Poorly written programs assume that their variables have values only when the variables are explicitly assigned values in the program code. With register_globals, this assumption is false. This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved. 285
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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 $value\n"; } 0 is spa
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The default argument, if provided,
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you need to answer questions like
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Example 5-3. Sorting arrays (contin
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Here’s how to randomize the order
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Sets Arrays let you implement the b
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Here’s the output from Example 5-
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Terminology Everyobject-oriented la
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You can use variable variables with
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} function set_name ($new_name) { $
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The object created bythe Person con
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Example 6-1. Displaying all declare
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Example 6-2. Object introspection f
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Here are some sample classes and ob
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PHP has two hooks for objects durin
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Example 6-5 shows the file next.php
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the request contains a blank line,
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SERVER_NAME The hostname, DNS alias
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The biggest difference between GET
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Figure 7-1. The chunkify form and i
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Example 7-4. Temperature conversion
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Example 7-6. Multiple selection val
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Example 7-8. Sticky multivalued che
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Files are stored in the server’s
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“me@aol” by requiring an at sig
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To mark a document as already expir
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A third technique for maintaining s
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Example 7-10. Preference selection
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Session basics To enable sessions f
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Custom storage By default, PHP stor
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When a session is completed, the de
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Chapter 8 CHAPTER 8 Databases PHP h
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columns, each of which has a name a
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Figure 8-1. The movie page the data
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$db = DB::connect($datasource); if
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string(4) "1962" ["name"]=> string(
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The executeMultiple( ) method takes
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echo "$k"; if (is_array($v)) { a_to
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Two HTML forms are needed to popula
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Example 8-3. Database connection ab
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Example 8-4. Backend administration
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Example 8-5. Adding a business (con
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Example 8-5. Adding a business (con
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The business listings page is illus
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The series of requests sent by the
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many colors as you need. The latter
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image-generating function. Example
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Example 9-4. Adding text to an imag
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Example 9-6. Displaying vertical Tr
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Example 9-8. Caching dynamic button
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You can also take this a step furth
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For a signed integer, the leftmost
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True Color Color Indexes The color
Page 233 and 234: Chapter 10 CHAPTER 10 PDF Adobe’s
Page 235 and 236: Figure 10-1. Hello world in a PDF d
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Page 239 and 240: Example 10-3. Changing the origin (
Page 241 and 242: Example 10-4. Text alignment within
Page 243 and 244: Example 10-5. Changing text attribu
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Page 249 and 250: Example 10-8. Nonproportional scali
Page 251 and 252: Figure 10-9. A sample path The pdf_
Page 253 and 254: The width and height parameters spe
Page 255 and 256: Example 10-11. Using a template Th
Page 257 and 258: Example 10-12. Using bookmarks and
Page 259 and 260: Example 10-13. Specifying a link (c
Page 261 and 262: Figure 10-16. Closed note The conte
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Page 265 and 266: Example 11-1. Generating an XML doc
Page 267 and 268: The end element handler is called w
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Page 275 and 276: Figure 11-2. Book details comment).
Page 277 and 278: Example 11-10. bookparse.xml (conti
Page 279 and 280: Example 11-12. News XSL transform
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Page 293 and 294: • Any system call (through functi
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Page 299 and 300: user.template. It uses the {DESTINA
Page 301 and 302: {ARTICLE} might be useful, as it wo
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Page 305 and 306: To turn off error reporting entirel
Page 307 and 308: Example 13-5. Log-rolling error han
Page 309 and 310: Before you begin optimization, ask
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Page 315 and 316: MySQL replication Sometimes the dat
Page 317 and 318: Chapter 14 CHAPTER 14 Extending PHP
Page 319 and 320: examples, and you are strongly enco
Page 321 and 322: int Integer/long long Same as int a
Page 323 and 324: zend_module_entry rot13_module_entr
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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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