Programming PHP

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echo To put a string into the HTML of a <strong>PHP</strong>-generated page, use echo. While it looks— and for the most part behaves—like a function, echo is a language construct. This means that you can omit the parentheses, so the following are equivalent: echo "Printy"; echo("Printy"); // also valid You can specify multiple items to print by separating them with commas: echo "First", "second", "third"; Firstsecondthird It is a parse error to use parentheses when trying to echo multiple values: // this is a parse error echo("Hello", "world"); Because echo is not a true function, you can’t use it as part of a larger expression: // parse error if (echo("test")) { echo("it worked!"); } Such errors are easily remedied, though, by using the print( ) or printf( ) functions. print( ) The print( ) function sends one value (its argument) to the browser. It returns true if the string was successfully displayed and false otherwise (e.g., if the user pressed the Stop button on her browser before this part of the page was rendered): if (! print("Hello, world")) { die("you're not listening to me!"); } Hello, world printf( ) The printf( ) function outputs a string built by substituting values into a template (the format string). It is derived from the function of the same name in the standard C library. The first argument to printf( ) is the format string. The remaining arguments are the values to be substituted in. A % character in the format string indicates a substitution. Format modifiers Each substitution marker in the template consists of a percent sign (%), possibly followed by modifiers from the following list, and ends with a type specifier. (Use '%%' to get a single percent character in the output.) The modifiers must appear in the order in which they are listed here: 76 | Chapter 4: Strings This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved.
• A padding specifier denoting the character to use to pad the results to the appropriate string size. Specify 0, a space, or any character prefixed with a single quote. Padding with spaces is the default. • A sign. This has a different effect on strings than on numbers. For strings, a minus (–) here forces the string to be right-justified (the default is to left-justify). For numbers, a plus (+) here forces positive numbers to be printed with a leading plus sign (e.g., 35 will be printed as +35). • The minimum number of characters that this element should contain. If the result is less than this number of characters, the sign and padding specifier govern how to pad to this length. • For floating-point numbers, a precision specifier consisting of a period and a number; this dictates how many decimal digits will be displayed. For types other than double, this specifier is ignored. Type specifiers The type specifier tells printf( ) what type of data is being substituted. This determines the interpretation of the previously listed modifiers. There are eight types, as listed in Table 4-2. Table 4-2. printf( ) type specifiers Specifier Meaning B The argument is an integer and is displayed as a binary number. C The argument is an integer and is displayed as the character with that value. d or I The argument is an integer and is displayed as a decimal number. e, E, or f The argument is a double and is displayed as a floating-point number. g or G The argument is a double with precision and is displayed as a floating-point number. O The argument is an integer and is displayed as an octal (base-8) number. S The argument is a string and is displayed as such. U The argument is an unsigned integer and is displayed as a decimal number. x The argument is an integer and is displayed as a hexadecimal (base-16) number; lowercase letters are used. X The argument is an integer and is displayed as a hexadecimal (base-16) number; uppercase letters are used. The printf( ) function looks outrageously complex to people who aren’t C programmers. Once you get used to it, though, you’ll find it a powerful formatting tool. Here are some examples: • A floating-point number to two decimal places: printf('%.2f', 27.452); 27.45 • Decimal and hexadecimal output: printf('The hex value of %d is %x', 214, 214); The hex value of 214 is d6 This is the Title of the Book, eMatter Edition Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved. Printing Strings | 77
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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
Page 25 and 26: PHP recognizes floating-point numbe
Page 27 and 28: • The empty string ("") and the s
Page 29 and 30: Chapter 6 describes classes and obj
Page 31 and 32: The old value of $black is lost. In
Page 33 and 34: update_counter( ); update_counter(
Page 35 and 36: Table 2-3. PHP operators P A Operat
Page 37 and 38: The division and multiplication ope
Page 39 and 40: Autoincrement and Autodecrement Ope
Page 41 and 42: Bitwise Operators The bitwise opera
Page 43 and 44: something is true. For example, you
Page 45 and 46: Because all operators are required
Page 47 and 48: if The if statement checks the trut
Page 49 and 50: A switch statement is given an expr
Page 51 and 52: if ($i == 5) break; // breaks out o
Page 53 and 54: This program adds the numbers from
Page 55 and 56: loops, and complain if the file bei
Page 57 and 58: XML Style Because of the advent of
Page 59 and 60: and other such niceties. Some will
Page 61 and 62: Chapter 3 CHAPTER 3 Functions A fun
Page 63 and 64: Typically, functions return some va
Page 65 and 66: As we discussed in Chapter 2, the e
Page 67 and 68: Example 3-5. Doubler redux function
Page 69 and 70: Missing Parameters PHP lets you be
Page 71 and 72: Anonymous Functions Some PHP functi
Page 73 and 74: echo "$who was $where"; Kilroy was
Page 75: As a special case, you can put a se
Page 79 and 80: Boolean values and NULL are not mea
Page 81 and 82: Changing Case PHP has several funct
Page 83 and 84: The quote_style and charset argumen
Page 85 and 86: Query-string encoding The urlencode
Page 87 and 88: The comparison operators (=) also w
Page 89 and 90: The Levenshtein algorithm calculate
Page 91 and 92: The str_repeat( ) function takes a
Page 93 and 94: print_r($a);Array ( [0] => Fred [1]
Page 95 and 96: The c in strcspn( ) stands for comp
Page 97 and 98: These three kinds of patterns can b
Page 99 and 100: Subpatterns You can use parentheses
Page 101 and 102: Table 4-8. POSIX anchors Anchor Mat
Page 103 and 104: Example 4-1. Credit-card validator
Page 105 and 106: Character Classes Perl-style regula
Page 107 and 108: Trailing Options Perl-style regular
Page 109 and 110: A simple use of positive lookahead
Page 111 and 112: For example: preg_match('/y.*e$/',
Page 113 and 114: Pass an array of strings as subject
Page 115 and 116: Quoting for regular expressions The
Page 117 and 118: Identifying Elements of an Array Yo
Page 119 and 120: array is almost always a programmer
Page 121 and 122: Two or more consecutive commas in t
Page 123 and 124: echo "true!\n"; } if (array_key_exi
Page 125 and 126: EXTR_PREFIX_SAME, which says that t
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echo "$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
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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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