passthru(3) [php man page]

PASSTHRU(3)								 1							       PASSTHRU(3)

passthru - Execute an external program and display raw output

SYNOPSIS

       void passthru (string  $command, [int  &$return_var])

DESCRIPTION

	The  passthru(3)  function  is	similar  to  the exec(3) function in that it executes a $command. This function should be used in place of
       exec(3) or system(3) when the output from the Unix command is binary data which needs to be passed directly back to the browser.  A  common
       use  for  this  is to execute something like the pbmplus utilities that can output an image stream directly. By setting the Content-type to
       image/gif and then calling a pbmplus program to output a gif, you can create PHP scripts that output images directly.

PARAMETERS

	      o $command
		- The command that will be executed.

	      o $return_var
		- If the $return_var argument is present, the return status of the Unix command will be placed here.

RETURN VALUES

	No value is returned.

NOTES

       Warning

	      When allowing user-supplied data to be passed to this function, use escapeshellarg(3) or escapeshellcmd(3) to ensure that users can-
	      not trick the system into executing arbitrary commands.

       Note

	      If a program is started with this function, in order for it to continue running in the background, the output of the program must be
	      redirected to a file or another output stream. Failing to do so will cause PHP to hang until the execution of the program ends.

       Note

	      When safe mode is enabled, you can only execute files within the safe_mode_exec_dir. For practical  reasons,  it	is  currently  not
	      allowed to have .. components in the path to the executable.

       Warning

	      With safe mode enabled, the command string is escaped with escapeshellcmd(3). Thus, echo y | echo x becomes echo y | echo x.

SEE ALSO

       exec(3), system(3), popen(3), escapeshellcmd(3), backtick operator.

PHP Documentation Group 													       PASSTHRU(3)

EXIT(3) 								 1								   EXIT(3)

exit - Output a message and terminate the current script

SYNOPSIS

       void exit ([string  $status])

DESCRIPTION

       void exit (int  $status)

	Terminates execution of the script. Shutdown functions and object destructors will always be executed even if exit is called.

       exit is a language construct and it can be called without parentheses if no $status is passed.

PARAMETERS

	      o $status
		- If $status is a string, this function prints the $status just before exiting.  If $status is an integer, that value will be used
		as the exit status and not printed. Exit statuses should be in the range 0 to 254, the exit status 255	is  reserved  by  PHP  and
		shall not be used. The status 0 is used to terminate the program successfully.

	      Note

		      PHP >= 4.2.0 does NOT print the $status if it is an integer.

RETURN VALUES

	No value is returned.

EXAMPLES

       Example #1

	      exit example

	      <?php

	      $filename = '/path/to/data-file';
	      $file = fopen($filename, 'r')
		  or exit("unable to open file ($filename)");

	      ?>

       Example #2

	      exit status example

	      <?php

	      //exit program normally
	      exit;
	      exit();
	      exit(0);

	      //exit with an error code
	      exit(1);
	      exit(0376); //octal

	      ?>

       Example #3

	      Shutdown functions and destructors run regardless

	      <?php
	      class Foo
	      {
		  public function __destruct()
		  {
		      echo 'Destruct: ' . __METHOD__ . '()' . PHP_EOL;
		  }
	      }

	      function shutdown()
	      {
		  echo 'Shutdown: ' . __FUNCTION__ . '()' . PHP_EOL;
	      }

	      $foo = new Foo();
	      register_shutdown_function('shutdown');

	      exit();
	      echo 'This will not be output.';
	      ?>

	      The above example will output:

	      Shutdown: shutdown()
	       Destruct: Foo::__destruct()

NOTES

       Note

	      Because this is a language construct and not a function, it cannot be called using variable functions.

       Note

	       This language construct is equivalent to die(3).

SEE ALSO

       register_shutdown_function(3).

PHP Documentation Group 														   EXIT(3)