cvs: phpdoc /en/language types.xml

jeroen Tue Aug 7 18:40:54 2001 EDT Modified files: /phpdoc/en/language types.xml Log: - Some Double -> float's - Some extra notes Index: phpdoc/en/language/types.xml diff -u phpdoc/en/language/types.xml:1.42 phpdoc/en/language/types.xml:1.43 --- phpdoc/en/language/types.xml:1.42 Fri Aug 3 15:22:34 2001 +++ phpdoc/en/language/types.xml Tue Aug 7 18:40:53 2001 @@ -1,4 +1,4 @@ -<!-- $Revision: 1.42 $ --> +<!-- $Revision: 1.43 $ --> <chapter id="language.types"> <title>Types</title> @@ -29,7 +29,7 @@ <listitem> <simpara> - <link linkend="language.types.double">floating-point number (double)</link> + <link linkend="language.types.double">floating-point number (float)</link> </simpara> </listitem> @@ -92,7 +92,7 @@ <simpara> In parameter definitions you can also encounter the 'number' pseudo-type, that indicates a parameter that is either <type>integer</type> or - <type>double</type>. + <type>float</type>. </simpara> --> </note> @@ -202,7 +202,7 @@ > 0 (zero) </simpara> </listitem> <listitem> - <simpara>the <link linkend="language.types.double">double</link> + <simpara>the <link linkend="language.types.double">float</link> 0.0 (zero) </simpara> </listitem> <listitem> @@ -292,12 +292,13 @@ --> The size of an integer is platform-dependent, although a maximum value of about two billion is the usual value - (that's 32 bits signed). + (that's 32 bits signed). PHP does not support unsigned + integers. </para> <note><!-- or warning? --> <simpara> In PHP there is no such thing as integer division. <literal>1/2</literal> - yields the <type>double</type> <literal>0.5</literal>. <!-- See + yields the <type>float</type> <literal>0.5</literal>. <!-- See ??? for more information. (with the operators, or with type-jug) --> </simpara> </note> @@ -307,7 +308,7 @@ <title>Integer overflow</title> <para> If you specify a number beyond the bounds of the <type>integer</type>-type, - it will be interpreted as a <type>double</type> instead. + it will be interpreted as a <type>float</type> instead. <informalexample> <programlisting role="php"> $large_number = 2147483647; @@ -315,18 +316,18 @@ // output: int(2147483647) $large_number = 2147483648; var_dump($large_number); -// output: float(2147483648) <!-- +// output: float(2147483648) -php is inconsistent here... -vardump says float, gettype says double +// this goes also for hexadecimal specified integers: ---> +var_dump( 0x80000000 ); +// output: float(2147483648) </programlisting> </informalexample> Furthermore, if some function or operator yields a number that is beyond the boundaries of <type>integer</type>, it will also be automatically converted to - <type>double</type>. + <type>float</type>. <informalexample> <programlisting role="php"> $million = 1000000; @@ -373,7 +374,7 @@ </simpara> </sect3> - <sect3 id="language.types.integer.casting.from-double"> + <sect3 id="language.types.integer.casting.from-float"> <title>From <link linkend="language.types.double">floating point numbers</link></title> <simpara> When converting from float to integer, the number will @@ -443,7 +444,7 @@ <sect1 id="language.types.double"> <title>Floating point numbers</title> <para> - Floating point numbers (AKA "doubles", "floats" or "real numbers") can be + Floating point numbers (AKA "floats", "doubles" or "real numbers") can be specified using any of the following syntaxes: <synopsis> $a = 1.234; $a = 1.2e3; $a = 7E-10; @@ -455,7 +456,7 @@ EXPONENT_DNUM (({LNUM}|{DNUM})[eE][+-]?{LNUM}) --> - The size of a floating point number is platform-dependent, + The size of a float is platform-dependent, although a maximum of ~1.8e308 with a precision of roughly 14 decimal digits is a common value (that's 64 bit IEEE format). </para> @@ -942,7 +943,7 @@ value and type are determined as follows. </simpara> <simpara> - The string will evaluate as a double if it contains any of the + The string will evaluate as a <type>float</type> if it contains any of the characters '.', 'e', or 'E'. Otherwise, it will evaluate as an integer. </simpara> @@ -1752,9 +1753,9 @@ </simpara> <para> An example of PHP's automatic type conversion is the addition - operator '+'. If any of the operands is a double, then all - operands are evaluated as doubles, and the result will be a - double. Otherwise, the operands will be interpreted as integers, + operator '+'. If any of the operands is a float, then all + operands are evaluated as floats, and the result will be a + float. Otherwise, the operands will be interpreted as integers, and the result will also be an integer. Note that this does NOT change the types of the operands themselves; the only change is in how the operands are evaluated. @@ -1765,7 +1766,7 @@ $foo++; // $foo is the string "1" (ASCII 49) --> $foo += 2; // $foo is now an integer (2) -$foo = $foo + 1.3; // $foo is now a double (3.3) +$foo = $foo + 1.3; // $foo is now a float (3.3) $foo = 5 + "10 Little Piggies"; // $foo is integer (15) $foo = 5 + "10 Small Pigs"; // $foo is integer (15) <!-- @@ -1849,7 +1850,7 @@ <informalexample> <programlisting role="php"> $foo = 10; // $foo is an integer -$bar = (double) $foo; // $bar is a double +$bar = (float) $foo; // $bar is a float </programlisting> </informalexample> </para> @@ -1863,7 +1864,7 @@ <simpara>(bool), (boolean) - cast to boolean</simpara> </listitem> <listitem> - <simpara>(real), (double), (float) - cast to double</simpara> + <simpara>(float), (double), (real) - cast to float</simpara> </listitem> <listitem> <simpara>(string) - cast to string</simpara> @@ -1993,4 +1994,5 @@ sgml-local-catalogs:nil sgml-local-ecat-files:nil End: +vim: ts=1 sw=1 et syntax=sgml -->