SERVER_SIGNATURE Syntax string SERVER_SIGNATURE Description The SERVER_SIGNATURE variable contains the server host name and version number.. SERVER_SOFTWARE Syntax string SERVER_SOF
Trang 1string SERVER_PROTOCOL
Description
The SERVER_PROTOCOL variable contains the name and version of the protocol used in the request For example, HTTP/1.1 is a valid value for SERVER_PROTOCOL
SERVER_SIGNATURE
Syntax
string SERVER_SIGNATURE
Description
The SERVER_SIGNATURE variable contains the server host name and version number
SERVER_SOFTWARE
Syntax
string SERVER_SOFTWARE
Description
The SERVER_SOFTWARE variable contains the server string, which is similar to a user-agent (or browser) string
PHP
The last section of this chapter contains PHP variables that are constant within the PHP installation Additionally, there are a couple of variables that are present when PHP scripts are run on the command line
argv
Syntax
array argv
Trang 2Description
The argv array contains a list of options passed to the PHP script if it was executed
on the command line
argc
Syntax
int argc
Description
The argc variable contains the number of options that were passed to the PHP script
if it was executed on the command line
PHP_SELF
Syntax
string PHP_SELF
Description
The PHP_SELF variable contains the filename of the script currently being processed, relative to the document root Please note that this variable is not available if you are running the PHP interpreter on the command line
HTTP_COOKIE_VARS
Syntax
array HTTP_COOKIE_VARS
Trang 3• <?php_track_vars?> (no longer supported in PHP 4)
• track_vars configuration file directive
HTTP_GET_VARS
Syntax
array HTTP_GET_VARS
Description
HTTP_GET_VARS contains an associative array of keys and values passed to the PHP script via the HTTP GET method of form submission This is available only if the tracking variables have been turned on within the PHP environment This can be accomplished in either of the following ways:
• <?php_track_vars?> (no longer supported in PHP 4)
• track_vars configuration file directive
HTTP_POST_VARS
Syntax
array HTTP_POST_VARS
Description
HTTP_POST_VARS contains an associative array of keys and values passed to the PHP script via the HTTP POST method of form submission This is available only if the tracking variables have been turned on within the PHP environment This can be accomplished in either of the following ways:
• <?php_track_vars?> (no longer supported in PHP 4)
• track_vars configuration file directive
Trang 4Chapter 5 PHP Language Extensions
This chapter primarily details which functions are available in PHP to work with numbers, arrays, and strings In addition, this chapter describes functions that provide information about the environment and variables that are available to the PHPs cript that is currently running
Arbitrary-Precision Mathematics
PHP's arbitrary-precision mathematics functions enable you to perform mathematical operations on real numbers, which include integers, longs, floats, and doubles The
term arbitrary-precision stems from the ability you have with these functions to specify a scale parameter Scale represents the number of digits to the right of the
decimal point in a number that should be considered in both the calculation and the output In PHP, arbitrary-precision numbers are represented as strings for parameters and return values
These functions are part of the bcmath library, which must be separately compiled into PHP (using enable-bcmath during configuration) because of licensing restrictions For more information, consult the readme.bcmath file that is included with the PHP source files
bcadd()
Syntax
string bcadd(string left_operand, string right_operand, [int scale])
Description
The bcadd() function calculates the sum of the left and right operands and returns the result as a string The optional scale parameter is used to indicate the number
of digits to the right of the decimal point in the result If scale is omitted, it defaults
to 0
echo bcadd(2.002,2.002,2);//result is 4.00
echo bcadd(2.009,2.009,2);//result is 4.00
bccomp()
Trang 5Description
The bccomp() function performs a numeric comparison on the left and right operands The result is +1 when the left_operand is greater than the
right_operand and –1 when the left_operand is less than the right_operand If
both are equal, the result is 0 The optional scale parameter is used to indicate the
number of digits to the right of the decimal point that should be considered in the comparison If scale is omitted, it defaults to 0
echo bccomp(2.005,2.009,2);//result is 0
echo bccomp(2.00,3.00,2);//result is -1
echo bccomp(3.00,2.00,2);//result is 1
bcdiv()
Syntax
string bcdiv(string left_operand, string right_operand, [int scale])
Description
The bcdiv() function calculates the quotient of the left_operand divided by the
right_operand The optional scale parameter indicates the number of digits to the
right of the decimal point in the result If scale is omitted, it defaults to 0 If the
right_operand is 0, a divide-by-zero warning will occur
echo bcdiv(2.005,1.009,2);//result is 2
echo bcdiv(10.00,3.00,2);//result is 3.33
echo bcdiv(2.00,3.00,2);//result is 0.66
echo bcdiv(2.00,0.005,2);//result is a divide by zero warning
bcmod()
Syntax
string bcmod(string left_operand, string modulus)
Description
The bcmod() function divides the left_operand by the modulus and returns the
remainder