PHP Developer’s Dictionary IT-SC book 250 Description The getprotobynumber() function returns the name associated with the protocol number defined by number. The name is retrieved from /etc/protocols. getservbyname() Syntax getservbyname(service, protocol); Description The getservbyname() function returns the port that corresponds to service and protocol . The services are retrieved from /etc/services file. Valid protocols are specified as TCP or UDP. getservbyport() Syntax getservbyport(port, protocol); Description The getservbyport() function returns the service which corresponds to port and protocol . The services are retrieved from /etc/services. Valid protocols are specified as TCP or UDP. openlog() Syntax openlog(ident, option, facility); Description The openlog() function opens a connection to the system logger. The string, ident, is added to each entry sent to the system log. Valid values for option are given in Table 7.3 and valid values for facility are given in Table 7.4. These values are also found in the manpage for syslog(3). Note PHP Developer’s Dictionary IT-SC book 251 The option LOG_PID is the only valid option in the Windows environment. Table 7.3. Valid Values for option Options Description LOG_PID Add the PID to each message. LOG_CONS If a message cannot be sent to the system log, send the message to the system console. LOG_ODELAY Delay opening the log until the first call to syslog. This is true by default. LOG_NDELAY Open the log immediately. Do not wait for the first call to syslog. LOG_NOWAIT Do not wait for child processes. The use of this flag is discouraged. LOG_PERROR Log all messages to stderr. Note LOG_USER is the only value for facility that is valid in the Windows environment. Table 7.4. Valid Values for facility Facility Description LOG_KERN Kernel messages LOG_USER Generic user-level messages (default) LOG_MAIL Mail subsystem LOG_DAEMON Other system daemons LOG_AUTH Security/authorization messages (deprecated; use LOG_AUTHPRIV instead) LOG_SYSLOG Messages generated internally by syslogd LOG_LPR Line printer subsystem LOG_NEWS Usenet news subsystem LOG_UUCP UUCP subsystem LOG_CRON Clock daemon (cron and at) LOG_AUTHPRIV Security/authorization messages pfsockopen() Syntax pfsockopen(hostname, port, [errno], [errstr], [timeout]); PHP Developer’s Dictionary IT-SC book 252 Description The pfsockopen() function is the persistent version of fsockopen(). Both functions establish a socket connection as a file stream. A TCP socket connection is established to hostname and port. The optional timeout parameter defines the timeout for the connect() system call. The pfsockopen() function does not close the socket connection upon completion of a read or write to the socket. If pfsockopen() is not successful, it will return false, 0. The optional variables errno and errstr will be set to indicate the system-level error that occurred. If pfsockopen() is successful, it will return a file pointer that can then be used by other file-related functions such as fputs() , fgets() , fclose() , and so on. set_socket_blocking() Syntax set_socket_blocking(socket descriptor, mode); Description The set_socket_blocking() function sets the blocking mode for the socket. If mode is false, 0, the socket descriptor will be switched to nonblocking mode. Setting mode to true, 1, will set the socket to blocking mode. In nonblocking mode, calls that get information from the socket will return immediately with data that is in the input buffer. In blocking mode, socket reads will halt execution until all the data available on the socket is received. syslog() Syntax syslog(priority, message); Description The syslog() function adds message with priority to the system log. Valid priorities are given in Table 7.5 . Note On Windows NT, the syslog service is provided through an emulator. The messages are logged in the NT Event Log and can be viewed by using the Event Viewer. PHP Developer’s Dictionary IT-SC book 253 Table 7.5. Priorities Priority Description LOG_EMERG This is a panic situation; the system is unstable. The message may be broadcast by the operating system to all users of the system. This message is translated to a warning on Windows. LOG_ALERT This is a situation that requires action to be taken immediately. It is translated into an error on Windows. LOG_CRIT This is a critical condition that can by be caused by external or hardware problems. This is translated to a warning on Windows. LOG_ERR These are general error conditions. These are translated to warnings on Windows. LOG_WARNING These are warnings, less severe than errors. LOG_NOTICE A notice is not an error, but is a significant condition requiring attention. This is translated to a warning on Windows. LOG_INFO Informational messages do not require any special action to be taken. LOG_DEBUG These messages are only debug-level messages. They are translated to warnings on Windows. Session Handling This section describes the session-handling functions that are included in the base PHP4 distribution. These functions allow session variables to be established and tracked per visitor. This functionality allows the user experience to vary depending on permissions, user-defined options, or environment. Sessions do not require variables to be stored in cookies, although it is possible, but rather session IDs are passed via the URL. In either case, these variables are stored and retrieved on the server through these PHP functions. session_start() Syntax session_start(); Description The session_start() function, which always returns true, allocates memory and establishes a session for the user. session_destroy() Syntax PHP Developer’s Dictionary IT-SC book 254 session_destroy(); Description The session_destroy() function, which always returns true, terminates the session and destroys all the data associated with the user's session. session_name() Syntax session_name([name]); Description The session_name() function returns the name of the current session as a string. If name is specified, the name of the current session is changed to name. session_module_name Syntax session_module_name([module]); Description The session_module_name() function returns the name of the current session module as a string. If module is specified, that module will be used. session_save_path() Syntax session_save_path([path]); Description . PHP Developer’s Dictionary IT-SC book 250 Description The getprotobynumber() function returns. facility are given in Table 7.4. These values are also found in the manpage for syslog(3). Note PHP Developer’s Dictionary IT-SC book 251 The option LOG_PID is the only valid option in the. messages pfsockopen() Syntax pfsockopen(hostname, port, [errno], [errstr], [timeout]); PHP Developer’s Dictionary IT-SC book 252 Description The pfsockopen() function is the persistent