Process Control Calls
Process Control Calls
Copyright(c) Management Analytics, 1995 - All Rights Reserved
Copyright(c), 1990, 1995 Dr. Frederick B. Cohen - All Rights Reserved
- The Exit call terminates the current process.
- The Fork call copies the current process. It returns
0 to the child process, and the Pid of the
child process to the parent process.
- The Exec call replaces the current process by loading
an executable program into the process memory and initializing
that program.
- The Alarm call schedules an interrupt for the current
process as a function of system events.
- The Kill call sends a ``signal'' to a process, which
the process can intercept and handle on its own, or in the
absence of an intercept routine, terminates the signalled
process. The ``kill'' signal (code number 9), cannot be
intercepted, and always kills a process if the sender has the
authority to send signals to that process.
- The Wait call causes the current process to become
inactive until a subprocess terminates. This prevents
unnecessary looping while waiting for subprocesses to terminate.
- The Signal call associates a function with the receipt of a
signal. This allows most signals to be caught and handled by the
process.
- The Pause call causes the current process to be
suspended until it receives a signal. This saves looping while a
process awaits an event from the environment.
- The Getpid call returns the Pid of the current
process.
- The Getuid call returns the Uid of the current
process.
- The Getgid call returns the Gid of the current
process.
- The Setuid call changes the Uid of the current
process (for the superuser).
- The Setgid call changes the Uid of the current
process (for the superuser).
- The Umask call gets andor sets the default protection
used for file creation.