PHP Developer’s Dictionary IT-SC book 140 Description The rand() function returns a psuedo-random number. The number returned will range between 0 and RAND_MAX or min and max , if they are specified. The random number should be seeded before using this function. round() Syntax double round(double val) Description The round() function returns the resulting number after rounding val . The val parameter is rounded up when it has a last digit of 5 or greater, and down when the last digit is less than 5. sin() Syntax float sin(float arg) Description The sin() function returns the sine of arg in radians. sqrt() Syntax float sqrt(float arg) Description The sqrt() function returns the square root of arg . echo sqrt(16);//displays 4 PHP Developer’s Dictionary IT-SC book 141 srand() Syntax void srand(int seed ) Description The srand() function seeds the random number generator with seed . This allows rand() to produce varying results. tan() Syntax float tan(float arg) Description The tan() function returns the tangent of arg in radians. Miscellaneous The functions in this section provide a variety of useful tools that don't lend themselves to a specific group of operations. Some of these tools include information regarding the current status of a connection with a browser along with information about that browser. Additionally, some debugging and language constructs dealing with script execution are included. connection_aborted() Syntax int connection_aborted(void ) Description The connection_aborted() function, which was added in PHP 3.0.7 and PHP 4.0b4, returns true if the client has disconnected. This is usually due to the user clicking the Stop button on his browser. PHP Developer’s Dictionary IT-SC book 142 connection_status() Syntax int connection_status(void ) Description The connection_status() function, which was added in PHP 3.0.7 and PHP 4.0b4, returns the connection status bit field. The result could indicate a NORMAL status, an ABORTED status, a TIMEOUT status, or a combination of both an ABORTED and TIMEOUT status, in the case that PHP is set to ignore user aborts and continue processing the script after the user aborts. connection_timeout() Syntax int connection_timeout(void ) Description The connection_timeout() function, which was added in PHP 3.0.7 and PHP 4.0b4, returns true if the script has timed out. define() Syntax int define(string name , mixed value , int [ case_insensitive ] ) Description The define() function declares a named constant. Named constants are similar to variables with the following exceptions: Constants are not referenced with a $ before the name. Constants do not have scope and therefore may be accessed equally from any part of your code. PHP Developer’s Dictionary IT-SC book 143 Redefinition of constants is not allowed. Constants may represent only scalar values. The third parameter, case_insensitive , is optional. If the value 1 is given, the constant will be defined as case insensitive. The default behavior is case sensitive. defined() Syntax int defined(string name) Description The defined() function returns true if name represents an existing named constant and returns false otherwise. die() Syntax void die(string message) Description The die() language construct outputs a message and stops parsing the script. There is no return. //if login unsuccessful die ("Unauthorized Access – Terminating"); eval() Syntax void eval(string code_str) Description PHP Developer’s Dictionary IT-SC book 144 The eval() function executes code_str as PHP code. The code_str must adhere to the normal PHP requirements, including the statement terminator. Any variables created in code_str will persist in the main code after function has executed. exit() Syntax void exit(void) Description The exit() language construct stops the current script from executing and does not return control to the script. func_get_arg() Syntax int func_get_arg(int arg_num) Description The func_get_arg() function, which was added in PHP 4.0b4, returns the argument located at the arg_num offset into a user-defined function's argument list. Arguments are numbered with a zero base. If not called from inside a user function, a warning will be generated. If arg_num is greater than the number of arguments the user-defined function has, a warning will be generated and a return value of false will be given. func_get_args() Syntax int func_gets_args(void ) Description The func_get_args() function, which was added in PHP 4.0b4, returns an array containing the arguments of the current user-defined function. The array counter is zero-based. This is similar to the argv[] parameter that is specified in the main . function, which was added in PHP 3.0.7 and PHP 4.0b4, returns true if the client has disconnected. This is usually due to the user clicking the Stop button on his browser. PHP Developer’s Dictionary. code_str) Description PHP Developer’s Dictionary IT-SC book 144 The eval() function executes code_str as PHP code. The code_str must adhere to the normal PHP requirements, including. connection_timeout(void ) Description The connection_timeout() function, which was added in PHP 3.0.7 and PHP 4.0b4, returns true if the script has timed out. define() Syntax int define(string