<big>int iof_flag(const char* '''format''', int '''row''', int '''col''', int* '''status''', int '''radio''');</big>
io_flag() allows the user to make a single true/false selection. '''"status"''' points to the status of the selection, that can be zero or non-zero. If '''"*status"''' is initially set to anything but zero, iof_flag() corrects value to one.'''"format"''' holds the shape of the checkbox as iof_displayflag() function.
io_flag() begins the selection by displaying the checkbox according to its '''“*status”'''. (Remember that the value of'''"*status"''' is corrected before the editing begins). Then the function waits for the user input.
* If the user input is any of the printable keys (' ' < key <= '~') excluding space, it should be ignored (no action taken). If the user input is any of the function keys, the function is terminated returning the key.