Thread: set to below priority for windows

Hello,

I am writing my program for windows and I am wondering how I can make my program run below low priority. If you know the code to set do this please let me know.

thanks.

Hello,

I've tried that link above but I can't get it to work. I don't think I am doing it right. How do I implment it in C/C++

thanks.

getdisk.cpp:32: error: `PROCESS_MODE_BACKGROUND_BEGIN' undeclared (first use
this function)
getdisk.cpp:32: error: (Each undeclared identifier is reported only once for
each function it appears in.)
getdisk.cpp:35: error: `ERROR_PROCESS_MODE_ALREADY_BACKGROUND' undeclared
(first use this function)
getdisk.cpp:38: error: label `Cleanup' used but not defined

getdisk.o - 4 error(s), 0 warning(s)

Code:

#include <stdio.h>
#include <stdlib.h>
#include <windows.h>

int main(){

DWORD dwError, dwPriClass;
	
	if(!SetPriorityClass(GetCurrentProcess(), PROCESS_MODE_BACKGROUND_BEGIN))
   {
      dwError = GetLastError();
      if( ERROR_PROCESS_MODE_ALREADY_BACKGROUND == dwError)
         printf("Already in background mode\n");
      else printf("Failed to enter background mode (%d)\n", dwError);
      goto Cleanup;
   } 

   // Display priority class

   dwPriClass = GetPriorityClass(GetCurrentProcess());

   printf("Current priority class is 0x%x\n", dwPriClass);

  return 0;
}

Background processing is only available on Vista. Even if you have Vista, it will probably require an update to your header and library files. You could use BELOW_NORMAL_PRIORITY_CLASS or IDLE_PRIORITY_CLASS instead.

I'm searching google for BELOW_NORMAL_PRIORITY_CLASS but haven't found any good documentation. can you recommend a source?

or let me know the small snip of code that will set my program to run in below low priority.

thanks.

Code:

SetPriorityClass(GetCurrentProcess(), BELOW_NORMAL_PRIORITY_CLASS);

should do it.

Code:

BOOL SetPriorityClass(
  HANDLE hProcess,        // handle to process
  DWORD dwPriorityClass   // priority class
);

dwPriorityClass is one of the following:

REALTIME_PRIORITY_CLASS
HIGH_PRIORITY_CLASS
ABOVE_NORMAL_PRIORITY_CLASS
NORMAL_PRIORITY_CLASS
BELOW_NORMAL_PRIORITY_CLASS
IDLE_PRIORITY_CLASS


be very careful with REALTIME_PRIORITY_CLASS . if your program uses a lot of cpu cycles it can hog your entire processor, preventing windows from responding even to the 3 finger salute.

Windows Task Manager, by default, is at high priority. If using high priority, I suggest putting Windows Task Manager to "Realtime" priority to make it easier to close (right-click on the process (taskmgr.exe) and choose set priority > Realtime to do so). If you encounter an infinite loop without doing this and realtime is set for your program and WTM is only high, you're doomed. I just thought I'd point this potential "hazard" out.