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Diffstat (limited to 'byterun/rotatecursor.h')
| -rw-r--r-- | byterun/rotatecursor.h | 57 |
1 files changed, 48 insertions, 9 deletions
diff --git a/byterun/rotatecursor.h b/byterun/rotatecursor.h index 8951c418d..53414e11c 100644 --- a/byterun/rotatecursor.h +++ b/byterun/rotatecursor.h @@ -5,29 +5,68 @@ /* Damien Doligez, projet Para, INRIA Rocquencourt */ /* */ /* Copyright 1996 Institut National de Recherche en Informatique et */ -/* Automatique. Distributed only by permission. */ +/* en Automatique. Distributed only by permission. */ /* */ /***********************************************************************/ /* $Id$ */ -/* Cursor rotation for MPW tools (ocamlrun and ocamlyacc) */ +/* Rotatecursor library, written by Damien Doligez + This file is in the public domain. + version 1.7 + + The goal of this library is to help implement cooperative multitasking + for MPW tools: to make sure that your program calls RotateCursor often + enough (about 20 times per second) but not too often (to avoid a big + slowdown). It can also be used in applications as soon as you have + an implementation of InitCursorCtl and RotateCursor (which is not hard + to do). + + Simplified usage: + + 1. #include this file where appropriate + 2. Insert the following line in the inner loop(s) of your program: + ROTATECURSOR_MAGIC (); + The overhead of this macro is only a few CPU cycles, so it can be + used without problem even in a tight loop. +*/ #ifndef _rotatecursor_ #define _rotatecursor_ -/* [have_to_interact] will be magically set to 1 when the time comes to - call [rotatecursor_action]. */ -extern int volatile have_to_interact; +/* [rotatecursor_flag] will be automagically set to 1 when the time comes + to call [rotatecursor_action]. +*/ +extern int volatile rotatecursor_flag; + -/* [*p1] and [have_to_interact] will be set to 1 when the time comes to - call [rotatecursor_action]. If p1 is not used, pass it as NULL. +/* Use [rotatecursor_options] to set advanced parameters: + + 1. [p1] is a pointer to another variable that will be set to 1 when + the time is up, unless it is already nonzero. Typical use is when + you already have a variable in your program that is set + asynchronously for something else, and you want to avoid testing + two different variables in your inner loop. Pass NULL if you don't + need this feature. + + 2. [period] is the interval (in milliseconds) between calls to + RotateCursor. Reasonable values are between 10 and 200; + the default is 50. */ -void rotatecursor_init (int volatile *p1); +void rotatecursor_options (int volatile *p1, int period); /* [reverse] is 0 to rotate the cursor clockwise, anything else to - rotate counterclockwise. This function always returns 0. + rotate counterclockwise. This function resets [rotatecursor_flag] + to 0. + This function always returns 0. It returns an int so you can use + it in an expression as well as a statement. Useful for some macros. */ int rotatecursor_action (int reverse); +/* Simple interface to [rotatecursor_flag] and [rotatecursor_action]. + Can be used as a statement (followed by a semicolon) or in an + expression (followed by a comma). +*/ +#define ROTATECURSOR_MAGIC() (rotatecursor_flag ? rotatecursor_action (0) : 0) + #endif /* _rotatecursor_ */ |