vi/cl/README.signal

15 *probably* start blocking around any imported function that we don't know
20 	can they handle interrupted system calls, so the vi routines that
21 	call DB block signals.  This means that DB routines could be
26 	switched vi into ex mode, and we continue that practice.
31 	that the screen will not resize until vi runs out of keys, but
32 	that doesn't seem like a problem.
44 	The up side is that there's no asynchronous behavior to worry about,
45 	and obviously no reentrancy problems.  The down side is that it's easy
54 	the place -- I hate to litter the source code with that.  For example,
63 	the exception that flow control and signals are turned on, and curses
67 	twiddle the tty.  I chose to use raw mode, on the grounds that raw
74 	The second problem is that vi permits you to enter literal signal
76 	can turn off signals when you get a ^V, but that means that a network
79 	talking over a protocol that recognizes signals locally and sends OOB
81 	character in vi, but that means that there's a race between entering
95 	work well for trying to detect infinite maps.  The problem is that
96 	you can write the code so that you don't have to turn on interrupts
98 	that an optimization doesn't cover up an infinite loop.  This also
113 	ignore signals.  It's also less likely that we'll miss a case, and we
117 	The down side is that we have to turn signals off if the user wants
122 	since we turn off flow control so that the user can enter literal
135 it: proof that drug testing is not making any significant headway in the
136 computer industry.  The 4BSD curses is deficient in that it does not have
140 The problem with this is that if we do our own SIGTSTP handling, in either
142 time, which means that we might be reentering curses, which is something we
151 that the only child in its foreground process group (of which it's aware)
154 that somewhere in the middle of all of this, vi is resetting the terminal,
159 and switch back to the original process group, where it sends that process
165 when it restarts that it can't repaint the screen until ex's child has
170 that we can pretty much guarantee that the user can interrupt any operation
171 at any time.  SIGTSTP is handled synchronously, so that we don't have to
172 reenter curses and so that we don't have to play the process group games.
174 also be recognized during operations that may potentially take a long time.