PHP – defined() Function
The PHP defined() function checks whether a constant exists.
The PHP dir() function returns an instance of the Directory class and is used to read a directory.
The PHP disk_free_space() function returns the free space, in bytes, of the specified filesystem or disk.
The PHP disk_total_space() function returns the total size, in bytes, of the specified filesystem or disk.
The PHP dns_check_record() function is an alias of the checkdnsrr() function.
The PHP dns_get_record() function gets the DNS resource records associated with the specified hostname.
The PHP easter_date() function returns the Unix timestamp for midnight on Easter of the current year, or a given year if specified.
The PHP easter_days() function returns the number of days after March 21, that the Easter Day is in the current year, or a given year if specified.
The PHP end() function moves the internal pointer to the last element in the array and outputs that element.
The PHP error_get_last() function returns the last error that occurred (as an associative array).
The PHP error_log() function sends an error message to a log, to a file, or to a mail account.
The PHP error_reporting() function specifies which errors are reported.
The PHP eval() function evaluates a string as PHP code (must be valid PHP code, not contain a return statement, and must end with semicolon).
The PHP Exception() constructor is used to create an Exception object and set some of its properties.
The PHP getCode() method returns an integer which can be used to identify the exception.
The PHP getFile() method returns the absolute path to the file where an exception occurred.
The PHP getLine() method returns the line number of the line of code which threw the exception.