class TUnixSystem: public TSystem

 Reset to original state.

 Initialize Unix system interface.

 Set the application name (from command line, argv[0]) and copy it in
 gProgName. Copy the application pathname in gProgPath.
 If name is 0 let the system set the actual executable name and path
 (works on MacOS X and Linux).

 Set DISPLAY environment variable based on utmp entry. Only for UNIX.

 Return system error string.

 Return the system's host name.

 Add a file handler to the list of system file handlers. Only adds
 the handler if it is not already in the list of file handlers.

 Remove a file handler from the list of file handlers. Returns
 the handler or 0 if the handler was not in the list of file handlers.

 Add a signal handler to list of system signal handlers. Only adds
 the handler if it is not already in the list of signal handlers.

 Remove a signal handler from list of signal handlers. Returns
 the handler or 0 if the handler was not in the list of signal handlers.

 If reset is true reset the signal handler for the specified signal
 to the default handler, else restore previous behaviour.

 If ignore is true ignore the specified signal, else restore previous
 behaviour.

 When the argument is true the SIGALRM signal handler is set so that
 interrupted syscalls will not be restarted by the kernel. This is
 typically used in case one wants to put a timeout on an I/O operation.
 By default interrupted syscalls will always be restarted (for all
 signals). This can be controlled for each a-synchronous TTimer via
 the method TTimer::SetInterruptSyscalls().

 Return the bitmap of conditions that trigger a floating point exception.

 Set which conditions trigger a floating point exception.
 Return the previous set of conditions.

 Dispatch a single event.

 Sleep milliSec milliseconds.

 Select on file descriptors. The timeout to is in millisec. Returns
 the number of ready descriptors, or 0 in case of timeout, or < 0 in
 case of an error, with -2 being EINTR and -3 EBADF. In case of EINTR
 the errno has been reset and the method can be called again. Returns
 -4 in case the list did not contain any file handlers or file handlers
 with file descriptor >= 0.

 Select on the file descriptor related to file handler h.
 The timeout to is in millisec. Returns the number of ready descriptors,
 or 0 in case of timeout, or < 0 in case of an error, with -2 being EINTR
 and -3 EBADF. In case of EINTR the errno has been reset and the method
 can be called again. Returns -4 in case the file handler is 0 or does
 not have a file descriptor >= 0.

 Handle and dispatch signals.

 Check if some signals were raised and call their Notify() member.

 Check if childs have finished.

 Check if there is activity on some file descriptors and call their
 Notify() member.

 Make a Unix file system directory. Returns 0 in case of success and
 -1 if the directory could not be created.

 Open a Unix file system directory. Returns 0 if directory does not exist.

 Close a Unix file system directory.

 Get next Unix file system directory entry. Returns 0 if no more entries.

 Change directory. Returns kTRUE in case of success, kFALSE otherwise.

 Return working directory.

 Return the user's home directory.

 Return a user configured or systemwide directory to create
 temporary files in.

 Create a secure temporary file by appending a unique
 6 letter string to base. The file will be created in
 a standard (system) directory or in the directory
 provided in dir. The full filename is returned in base
 and a filepointer is returned for safely writing to the file
 (this avoids certain security problems). Returns 0 in case
 of error.

 Concatenate a directory and a file name.

 Returns FALSE if one can access a file using the specified access mode.
 Mode is the same as for the Unix access(2) function.
 Attention, bizarre convention of return value!!

 Copy a file. If overwrite is true and file already exists the
 file will be overwritten. Returns 0 when successful, -1 in case
 of file open failure, -2 in case the file already exists and overwrite
 was false and -3 in case of error during copy.

 Rename a file. Returns 0 when successful, -1 in case of failure.

 Returns TRUE if the url in 'path' points to the local file system.
 This is used to avoid going through the NIC card for local operations.

 Get info about a file. Info is returned in the form of a FileStat_t
 structure (see TSystem.h).
 The function returns 0 in case of success and 1 if the file could
 not be stat'ed.

 Get info about a file system: id, bsize, bfree, blocks.
 Id      is file system type (machine dependend, see statfs())
 Bsize   is block size of file system
 Blocks  is total number of blocks in file system
 Bfree   is number of free blocks in file system
 The function returns 0 in case of success and 1 if the file system could
 not be stat'ed.

 Create a link from file1 to file2. Returns 0 when successful,
 -1 in case of failure.

 Create a symlink from file1 to file2. Returns 0 when succesfull,
 -1 in case of failure.

 Unlink, i.e. remove, a file or directory. Returns 0 when succesfull,
 -1 in case of failure.

 Expand a pathname getting rid of special shell characters like ~.$, etc.
 For Unix/Win32 compatibility use $(XXX) instead of $XXX when using
 environment variables in a pathname. If compatibility is not an issue
 you can use on Unix directly $XXX. Returns kFALSE in case of success
 or kTRUE in case of error.

 Expand a pathname getting rid of special shell characters like ~.$, etc.
 For Unix/Win32 compatibility use $(XXX) instead of $XXX when using
 environment variables in a pathname. If compatibility is not an issue
 you can use on Unix directly $XXX. Returns kFALSE in case of success
 or kTRUE in case of error.

 Set the file permission bits. Returns -1 in case or error, 0 otherwise.

 Set the process file creation mode mask.

 Set a files modification and access times. If actime = 0 it will be
 set to the modtime. Returns 0 on success and -1 in case of error.

 Find location of file "wfil" in a search path.
 The search path is specified as a : separated list of directories.
 Return value is pointing to wfile for compatibility with
 Which(const char*,const char*,EAccessMode) version.

 Returns the user's id. If user = 0, returns current user's id.

 Returns the effective user id. The effective id corresponds to the
 set id bit on the file being executed.

 Returns the group's id. If group = 0, returns current user's group.

 Returns the effective group id. The effective group id corresponds
 to the set id bit on the file being executed.

 Returns all user info in the UserGroup_t structure. The returned
 structure must be deleted by the user. In case of error 0 is returned.

 Returns all user info in the UserGroup_t structure. If user = 0, returns
 current user's id info. The returned structure must be deleted by the
 user. In case of error 0 is returned.

 Returns all group info in the UserGroup_t structure. The only active
 fields in the UserGroup_t structure for this call are:
    fGid and fGroup
 The returned structure must be deleted by the user. In case of
 error 0 is returned.

 Returns all group info in the UserGroup_t structure. The only active
 fields in the UserGroup_t structure for this call are:
    fGid and fGroup
 If group = 0, returns current user's group. The returned structure
 must be deleted by the user. In case of error 0 is returned.

 Set environment variable. The string passed will be owned by
 the environment and can not be reused till a "name" is set
 again. The solution below will lose the space for the string
 in that case, but if this functions is not called thousands
 of times that should not be a problem.

 Get environment variable.

 Execute a command.

 Open a pipe.

 Close the pipe.

 Get process id.

 Exit the application.

 Abort the application.

 Print a stack trace.

 Open connection to system log daemon. For the use of the options and
 facility see the Unix openlog man page.

 Send mess to syslog daemon. Level is the logging level and mess the
 message that will be written on the log.

 Close connection to system log daemon.

 Redirect standard output (stdout, stderr) to the specified file.
 If the file argument is 0 the output is set again to stderr, stdout.
 The second argument specifies whether the output should be added to the
 file ("a", default) or the file be truncated before ("w").
 This function saves internally the current state into a static structure.
 The call can be made reentrant by specifying the opaque structure pointed
 by 'h', which is filled with the relevant information. The handle 'h'
 obtained on the first call must then be used in any subsequent call,
 included ShowOutput, to display the redirected output.
 Returns 0 on success, -1 in case of error.

dynamic linking of module

 Load a shared library. Returns 0 on successful loading, 1 in
 case lib was already loaded and -1 in case lib does not exist
 or in case of error.

 Unload a shared library.

 List symbols in a shared library.

 List all loaded shared libraries.

 Get list of shared libraries loaded at the start of the executable.
 Returns 0 in case list cannot be obtained or in case of error.

 Return current time.

 Handle and dispatch timers. If mode = kTRUE dispatch synchronous
 timers else a-synchronous timers.

 Add timer to list of system timers.

 Remove timer from list of system timers.

 Reset a-sync timer.

 Get Internet Protocol (IP) address of host. Returns an TInetAddress
 object. To see if the hostname lookup was successfull call
 TInetAddress::IsValid().

 Get Internet Protocol (IP) address of host and port #.

 Get Internet Protocol (IP) address of remote host and port #.

 Get port # of internet service.

 Get name of internet service.

 Connect to service servicename on server servername.

 Open a connection to a service on a server. Returns -1 in case
 connection cannot be opened.
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Is called via the TSocket constructor.

 Announce TCP/IP service.
 Open a socket, bind to it and start listening for TCP/IP connections
 on the port. If reuse is true reuse the address, backlog specifies
 how many sockets can be waiting to be accepted.
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Returns socket fd or -1 if socket() failed, -2 if bind() failed
 or -3 if listen() failed.

 Announce unix domain service on path "kServerPath/<port>"

 Announce unix domain service on path 'sockpath'

 Accept a connection. In case of an error return -1. In case
 non-blocking I/O is enabled and no connections are available
 return -2.

 Close socket.

 Receive a buffer headed by a length indicator. Lenght is the size of
 the buffer. Returns the number of bytes received in buf or -1 in
 case of error.

 Send a buffer headed by a length indicator. Returns length of sent buffer
 or -1 in case of error.

 Receive exactly length bytes into buffer. Use opt to receive out-of-band
 data or to have a peek at what is in the buffer (see TSocket). Buffer
 must be able to store at least length bytes. Returns the number of
 bytes received (can be 0 if other side of connection was closed) or -1
 in case of error, -2 in case of MSG_OOB and errno == EWOULDBLOCK, -3
 in case of MSG_OOB and errno == EINVAL and -4 in case of kNoBlock and
 errno == EWOULDBLOCK. Returns -5 if pipe broken or reset by peer
 (EPIPE || ECONNRESET).

 Send exactly length bytes from buffer. Use opt to send out-of-band
 data (see TSocket). Returns the number of bytes sent or -1 in case of
 error. Returns -4 in case of kNoBlock and errno == EWOULDBLOCK.
 Returns -5 if pipe broken or reset by peer (EPIPE || ECONNRESET).

 Set socket option.

 Get socket option.

 Set a signal handler for a signal.

 If ignore is true ignore the specified signal, else restore previous
 behaviour.

 When the argument is true the SIGALRM signal handler is set so that
 interrupted syscalls will not be restarted by the kernel. This is
 typically used in case one wants to put a timeout on an I/O operation.
 By default interrupted syscalls will always be restarted (for all
 signals). This can be controlled for each a-synchronous TTimer via
 the method TTimer::SetInterruptSyscalls().

 Return the signal name associated with a signal.

 Restore old signal handler for specified signal.

 Restore old signal handlers.

 Get current time in milliseconds since 0:00 Jan 1 1995.

 Set interval timer to time-out in ms milliseconds.

 Wait for events on the file descriptors specified in the readready and
 writeready masks or for timeout (in milliseconds) to occur. Returns
 the number of ready descriptors, or 0 in case of timeout, or < 0 in
 case of an error, with -2 being EINTR and -3 EBADF. In case of EINTR
 the errno has been reset and the method can be called again.

 Returns the user's home directory.

 Make a Unix file system directory. Returns 0 in case of success and
 -1 if the directory could not be created (either already exists or
 illegal path name).

 Open a directory.

 Returns the next directory entry.

 Get info about a file. Info is returned in the form of a FileStat_t
 structure (see TSystem.h).
 The function returns 0 in case of success and 1 if the file could
 not be stat'ed.

 Get info about a file system: id, bsize, bfree, blocks.
 Id      is file system type (machine dependend, see statfs())
 Bsize   is block size of file system
 Blocks  is total number of blocks in file system
 Bfree   is number of free blocks in file system
 The function returns 0 in case of success and 1 if the file system could
 not be stat'ed.

 Wait till child is finished.

 Open a TCP/IP connection to server and connect to a service (i.e. port).
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Is called via the TSocket constructor. Returns -1 in case of error.

 Connect to a Unix domain socket.

 Connect to a Unix domain socket. Returns -1 in case of error.

 Open a socket, bind to it and start listening for TCP/IP connections
 on the port. If reuse is true reuse the address, backlog specifies
 how many sockets can be waiting to be accepted. If port is 0 a port
 scan will be done to find a free port. This option is mutual exlusive
 with the reuse option.
 Use tcpwindowsize to specify the size of the receive buffer, it has
 to be specified here to make sure the window scale option is set (for
 tcpwindowsize > 65KB and for platforms supporting window scaling).
 Returns socket fd or -1 if socket() failed, -2 if bind() failed
 or -3 if listen() failed.

 Open a socket, bind to it and start listening for Unix domain connections
 to it. Returns socket fd or -1.

 Open a socket on path 'sockpath', bind to it and start listening for Unix
 domain connections to it. Returns socket fd or -1.

 Receive exactly length bytes into buffer. Returns number of bytes
 received. Returns -1 in case of error, -2 in case of MSG_OOB
 and errno == EWOULDBLOCK, -3 in case of MSG_OOB and errno == EINVAL
 and -4 in case of kNoBlock and errno == EWOULDBLOCK.
 Returns -5 if pipe broken or reset by peer (EPIPE || ECONNRESET).

 Send exactly length bytes from buffer. Returns -1 in case of error,
 otherwise number of sent bytes. Returns -4 in case of kNoBlock and
 errno == EWOULDBLOCK. Returns -5 if pipe broken or reset by peer
 (EPIPE || ECONNRESET).

 Return the dynamic path (used to find shared libraries).

 Set the dynamic path to a new value.
 If the value of 'path' is zero, the dynamic path is reset to its
 default value.

 Returns the path of a shared library (searches for library in the
 shared library search path). If no file name extension is provided
 it first tries .so, .sl, .dl and then .a (for AIX). The returned string
 must be deleted.

 Returns the handle to a loaded shared library. Returns 0 when library
 not loaded.

 Load a shared library. Returns 0 on successful loading, 1 in
 case lib was already loaded and -1 in case lib does not exist
 or in case of error.

 Finds and returns a function pointer to a symbol in the shared library.
 Returns 0 when symbol not found.

 List symbols in a shared library. One can use wildcards to list only
 the interesting symbols.

 List all loaded shared libraries.

 Unload a shared library.

 Read utmp file. Returns number of entries in utmp file.

 Look for utmp entry which is connected to terminal tty.

 Returns static system info, like OS type, CPU type, number of CPUs
 RAM size, etc into the SysInfo_t structure. Returns -1 in case of error,
 0 otherwise.

 Returns cpu load average and load info into the CpuInfo_t structure.
 Returns -1 in case of error, 0 otherwise. Use sampleTime to set the
 interval over which the CPU load will be measured, in ms (default 1000).

 Returns ram and swap memory usage info into the MemInfo_t structure.
 Returns -1 in case of error, 0 otherwise.

 Returns cpu and memory used by this process into the ProcInfo_t structure.
 Returns -1 in case of error, 0 otherwise.