bin@primate.wisc.edu (Brain in Neutral) (01/05/91)
Tech Note 202 (Resetting the Event Mask) says the event mask should be saved/restored at the beginning/end of a program that modifies it, e.g., # define SysEvtMask 0x0144 saveMask = * ((Integer *) SysEvtMask; ... SetEventMask (newMask); ... * ((Integer *) SysEvtMask = saveMask My question: why not just reset at the end with SetEventMask (saveMask)? Is there some difference between that and setting the low memory global directly? -- Paul DuBois dubois@primate.wisc.edu
phils@chaos.cs.brandeis.edu (Phil Shapiro) (01/05/91)
In article <3687@uakari.primate.wisc.edu> bin@primate.wisc.edu (Brain in Neutral) writes:
Tech Note 202 (Resetting the Event Mask) says the event mask should be
saved/restored at the beginning/end of a program that modifies it, e.g.,
# define SysEvtMask 0x0144
saveMask = * ((Integer *) SysEvtMask;
...
SetEventMask (newMask);
...
* ((Integer *) SysEvtMask = saveMask
My question: why not just reset at the end with SetEventMask (saveMask)?
Is there some difference between that and setting the low memory global
directly?
There's no difference, SetEventMask() is [Not in ROM] -- it's
implemented with glue that writes directly to the low memory global.
I would still use the function instead, just in case this changes.
The tech note writers were probably just being absent-minded. BTW,
you can skip some hassle and use the definition of SysEvtMask() from
EventMgr.h, if you're using Think C.
-phil
--
Phil Shapiro Technical Support Analyst
Language Products Group Symantec Corporation
Internet: phils@chaos.cs.brandeis.edu
--
Phil Shapiro Technical Support Analyst
Language Products Group Symantec Corporation
Internet: phils@chaos.cs.brandeis.edu