> Pete's First Rule Of Idle Class:  the idle class priority level of 0
> is reserved for Pulse;  use 1-31 for your programs.  Example

>    DosSetPriority( PRTYS_THREAD, PRTYC_IDLETIME, 1, 0 );

 jl> Do you mean that values -31...-1 shouldn't be used at all?


Priority levels range from 0 to 31.  It is a common error to think that
this is valid:

 DosSetPriority( PRTYS_THREAD, PRTYC_IDLETIME, -31, 0 );

 (or,  if you like,  replace -31 with PRTYD_MINIMUM).


The *only* time the negative values are used is when the class parameter is
"PRTYC_NOCHANGE";  for all other values,  the priorty argment is
a SETTING, not a DELTA.

I have rarely seen PRTYC_NOCHANGE in a program,  but see negative values
all the time.

Check out this little program (I wrote it in 16bits because DosGetPrty() is
less hassle than DosGetInfoBlocks()):

 // msc: cl /Ox /W3 /Lp prty.c
 #define INCL_NOPM
 #define INCL_DOS
 #include 
 #include 



 static void show(void)
 {
     USHORT v;
     DosGetPrty(0, &v, 0);
     printf("Current priority = %04x\n",  v);
 }

 int main(void)
 {
     int i;

     DosSetPrty(PRTYS_THREAD, PRTYC_REGULAR, 31, 0);

     printf("START\n");
     show();

     printf("\nTrying a DELTA in a specified class (invalid):\n");
     for(i=0; i<5; i++){
         DosSetPrty(PRTYS_THREAD, PRTYC_REGULAR, -1, 0);
         show();
     }

     printf("\nTrying a positive DELTA in current class (valid):\n");
     for(i=0; i<5; i++){
         DosSetPrty(PRTYS_THREAD, PRTYC_NOCHANGE, 1, 0);
         show();
     }

     printf("\nTrying a negative DELTA in current class (valid):\n");
     for(i=0; i<5; i++){
         DosSetPrty(PRTYS_THREAD, PRTYC_NOCHANGE, -1, 0);
         show();
     }
 }


The output:

 START
 Current priority = 021f

 Trying a DELTA in a specified class (invalid):
 Current priority = 0200
 Current priority = 0200
 Current priority = 0200
 Current priority = 0200
 Current priority = 0200

 Trying a positive DELTA in current class (valid):
 Current priority = 0201
 Current priority = 0202
 Current priority = 0203
 Current priority = 0204
 Current priority = 0205

 Trying a negative DELTA in current class (valid):
 Current priority = 0204
 Current priority = 0203
 Current priority = 0202
 Current priority = 0201
 Current priority = 0200

--- Maximus/2 2.02p1