tcgetpgrpint

tcgetpgrpint is a function in the POSIX terminal control API. It is used to retrieve the process group ID of the foreground process group in a given terminal. The function takes a file descriptor representing the terminal as an argument. The file descriptor is typically obtained using functions like open() or tcgetattr(). tcgetpgrpint returns the process group ID of the foreground process group on success. If an error occurs, it returns -1 and sets the errno variable to indicate the specific error. Common errors include EBADF if the file descriptor is invalid, ENOTTY if the file descriptor is not associated with a terminal, or EIO if an I/O error occurs. The foreground process group is the process group that currently has control of the terminal. This is important for handling signals and user input, as signals like SIGINT (generated by Ctrl+C) are typically sent to the foreground process group. Understanding and using tcgetpgrpint allows programs to interact more effectively with the terminal environment and manage process group behavior.