Programming PHP

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FreeType Support enabled FreeType Linkage with freetype JPG Support enabled PNG Support enabled WBMP Support enabled Pay close attention to the image types listed. These are the types of images you will be able to generate. There have been three major revisions of GD and its API. Versions of GD before 1.6 support only the GIF format. Version 1.6 and later support JPEG, PNG, and WBMP, but not GIF (the GIF file format uses patented algorithms that require royalties). Version 2.x of GD added several new drawing primitives. All GD 1.x versions are limited to 8-bit color. That is, the images you generate or manipulate with GD 1.x can contain only 256 different colors. For simple charts or graphs this is more than sufficient, but if you are dealing with photos or other images with more than 256 colors you will find the results less than satisfactory. Upgrade to GD 2.x to get true-color support, or use the Imlib2 library and corresponding <strong>PHP</strong> extension instead. The API for the Imlib2 extension is somewhat different from the GD extension API and is not covered in this chapter. Basic Graphics Concepts An image is a rectangle of pixels that have various colors. Colors are identified by their position in the palette, an array of colors. Each entry in the palette has three separate color values—one for red, one for green, and one for blue. Each value ranges from 0 (this color not present) to 255 (this color at full intensity). Image files are rarely a straightforward dump of the pixels and the palette. Instead, various file formats (GIF, JPEG, PNG, etc.) have been created that attempt to compress the data somewhat to make smaller files. Different file formats handle image transparency, which controls whether and how the background shows through the image, in different ways. Some support an alpha channel, an extra value for every pixel reflecting the transparency at that point. Others simply designate one entry in the palette as indicating transparency. Antialiasing is where pixels at the edge of a shape are moved or recolored to make a gradual transition between the shape and its background. This prevents the rough and jagged edges that can make for unappealing images. Some functions that draw on an image implement antialiasing. With 256 possible values for each of red, green, and blue, there are 16,777,216 possible colors for every pixel. Some file formats limit the number of colors you can have in a palette (e.g., GIF supports no more than 256 colors); others let you have as 216 | Chapter 9: Graphics This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved.
many colors as you need. The latter are known as true color formats, because 24-bit color (8 bits for each of red, green, and blue) gives more hues than the human eye can distinguish. Creating and Drawing Images For now, let’s start with the simplest possible GD example. Example 9-1 is a script that generates a black filled square. The code works with any version of GD that supports the PNG image format. Example 9-1. A black square on a white background (black.php) Example 9-1 illustrates the basic steps in generating any image: creating the image, allocating colors, drawing the image, and then saving or sending the image. Figure 9-1 shows the output of Example 9-1. Figure 9-1. A black square on a white background To see the result, simply point your browser at the black.php <strong>PHP</strong> page. To embed this image in a web page, use: The Structure of a Graphics Program Most dynamic image-generation programs followthe same basic steps outlined in Example 9-1. You can create a 256-color image with the ImageCreate( ) function, which returns an image handle: $image = ImageCreate(width, height); This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved. Creating and Drawing Images | 217
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Programming PHP
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Programming PHP by Rasmus Lerdorf a
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Colophon Our look is the result of
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Accessing Individual Characters 79
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Concealing PHP Libraries 293 PHP Co
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clarify the explanations, and the p
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There is a web page for this book,
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Chapter 2 CHAPTER 2 Language Basics
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Comments Comments give information
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*/ echo("l=$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
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
Page 175 and 176: “me@aol” by requiring an at sig
Page 177 and 178: To mark a document as already expir
Page 179 and 180: A third technique for maintaining s
Page 181 and 182: Example 7-10. Preference selection
Page 183 and 184: Session basics To enable sessions f
Page 185 and 186: Custom storage By default, PHP stor
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
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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: The series of requests sent by the
Page 219 and 220: image-generating function. Example
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
Page 229 and 230: For a signed integer, the leftmost
Page 231 and 232: 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
Page 237 and 238: Type, Content-Disposition, and Cont
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
Page 245 and 246: usr/share/fonts FontAFM LuciduxSans
Page 247 and 248: Adding an image to a PDF document i
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
Page 263 and 264: In HTML, you often have an open tag
Page 265 and 266: 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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